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Cloning of a Ca(2+)-ATPase gene and the role of cytosolic Ca2+ in the gibberellin-dependent signaling pathway in aleurone cells. Chen X,Chang M,Wang B,Wu B The Plant journal : for cell and molecular biology The ultimate goal of this investigation was to identify intermediary steps in the gibberellin (GA)-dependent signaling pathway in rice aleurone cells. By using a differential display approach, a number of putative GA-responsive genes were isolated. One of them, a GA-responsive Ca(2+)-ATPase gene, was identified and partially characterized. A genomic clone and a cDNA clone were isolated and sequenced. The deduced amino acid sequence showed that this protein resembles an endoplasmic reticulum membrane Ca(2+)-ATPase. In a transient assay in rice aleurone cells, expression of the introduced Ca(2+)-ATPase cDNA bypassed the GA requirement for stimulating the expression of a major target gene, the alpha-amylase c gene (Osamy-c). This result suggests that GA-dependent expression of this Ca(2+)-ATPase gene (OsCa-atpase) plays an important role in the GA-dependent signal-transduction pathway. To investigate the possible involvement of other proteins and genes that may affect the intracellular Ca2+ level, compounds which can block different putative steps in the signal-transduction pathway were introduced into rice aleurone cells, and then the level of the OsCa-atpase transcript or the Osamy-c transcript was monitored. In the presence of GA, the rice Ca(2+)-ATPase and the Ca2+ channels appeared to co-regulate the local concentration of cytosolic Ca2+. The release of Ca2+ from the internal stores to the cytoplasm was presumably initiated by inositol-1,4,5-triphosphate which reached a peak level within 25 min after GA induction. As a second messenger, Ca2+ binds to calmodulin (CaM), and the Ca2+/CaM complex regulates the cytosolic Ca2+ by affecting expression of the OsCa-atpase. Finally, a working model is proposed for the GA-dependent signaling pathway in aleurone cells.
Physiological and Transcriptomic Analysis Reveals Distorted Ion Homeostasis and Responses in the Freshwater Plant L. under Salt Stress. Fu Lili,Ding Zehong,Sun Xuepiao,Zhang Jiaming Genes Duckweeds are a family of freshwater angiosperms with morphology reduced to fronds and propagation by vegetative budding. Unlike other angiosperm plants such as and rice that have physical barriers between their photosynthetic organs and soils, the photosynthetic organs of duckweeds face directly to their nutrient suppliers (waters), therefore, their responses to salinity may be distinct. In this research, we found that the duckweed L. accumulated high content of sodium and reduced potassium and calcium contents in large amounts under salt stress. Fresh weight, Rubisco and AGPase activities, and starch content were significantly decreaseded in the first day but recovered gradually in the following days and accumulated more starch than control from Day 3 to Day 5 when treated with 100 mM and 150 mM NaCl. A total of 2156 differentially expressed genes were identified. Overall, the genes related to ethylene metabolism, major CHO degradation, lipid degradation, N-metabolism, secondary metabolism of flavonoids, and abiotic stress were significantly increased, while those involved in cell cycle and organization, cell wall, mitochondrial electron transport of ATP synthesis, light reaction of photosynthesis, auxin metabolism, and tetrapyrrole synthesis were greatly inhibited. Moreover, salt stress also significantly influenced the expression of transcription factors that are mainly involved in abiotic stress and cell differentiation. However, most of the osmosensing calcium antiporters (OSCA) and the potassium inward channels were downregulated, Na/H antiporters (SOS1 and NHX) and a Na/Ca exchanger were slightly upregulated, but most of them did not respond significantly to salt stress. These results indicated that the ion homeostasis was strongly disturbed. Finally, the shared and distinct regulatory networks of salt stress responses between duckweeds and other plants were intensively discussed. Taken together, these findings provide novel insights into the underlying mechanisms of salt stress response in duckweeds, and can be served as a useful foundation for salt tolerance improvement of duckweeds for the application in salinity conditions. 10.3390/genes10100743
Heterogeneous expression of plasma-membrane-localised OsOSCA1.4 complements osmotic sensing based on hyperosmolality and salt stress in Arabidopsis osca1 mutant. Zhai Yuanjun,Wen Zhaohong,Han Yang,Zhuo Wenqing,Wang Fang,Xi Chao,Liu Jin,Gao Ping,Zhao Heping,Wang Yingdian,Wang Youjun,Han Shengcheng Cell calcium In plants, both hyperosmolality and salt stress induce cytosolic calcium increases within seconds, referred to as the hyperosmolality-induced [Ca] increases, OICI, and salt stress-induced [Ca] increases, SICI. Previous studies have shown that Arabidopsis reduced hyperosmolality-induced [Ca] increase 1 (OSCA1.1) encodes a hyperosmolality-gated calcium-permeable channel that mediates OICI in guard cells and root cells. Multiple OSCA members exist in plants; for example, Oryza sativa has 11 OsOSCAs genes, indicating that OSCAs have diverse biological functions. Here, except for OsOSCA4.1, ten full-length OsOSCAs were separately subcloned, in which OsOSCA1.4 was exclusively localised to the plasma membrane and other nine OsOSCAs-eYFP co-localised with an endoplasmic reticulum marker in Arabidopsis mesophyll protoplasts. OsOSCA1.4 was further identified as a calcium-permeable ion channel that activates an inward current after receiving an osmotic signal exerted by hyperosmolality or salt stress, and mediates OICI and SICI in human embryonic kidney 293 (HEK293) cells. Moreover, overexpression of OsOSCA1.4 in Arabidopsis osca1 mutant complemented osmotic Ca signalling, root growth, and stomatal movement in response to hyperosmolality and salt stress. These results will facilitate further study of OsOSCA-mediated calcium signalling and its distinct roles in rice growth and development. 10.1016/j.ceca.2020.102261
Expression and localization of the mechanosensitive/osmosensitive ion channel TMEM63B in the mouse urinary tract. Physiological reports The epithelial cells that line the kidneys and lower urinary tract are exposed to mechanical forces including shear stress and wall tension; however, the mechanosensors that detect and respond to these stimuli remain obscure. Candidates include the OSCA/TMEM63 family of ion channels, which can function as mechanosensors and osmosensors. Using Tmem63b reporter mice, we assessed the localization of HA-tagged-TMEM63B within the urinary tract by immunofluorescence coupled with confocal microscopy. In the kidneys, HA-TMEM63B was expressed by proximal tubule epithelial cells, by the intercalated cells of the collecting duct, and by the epithelial cells lining the thick ascending limb of the medulla. In the urinary tract, HA-TMEM63B was expressed by the urothelium lining the renal pelvis, ureters, bladder, and urethra. HA-TMEM63B was also expressed in closely allied organs including the epithelial cells lining the seminal vesicles, vas deferens, and lateral prostate glands of male mice and the vaginal epithelium of female mice. Our studies reveal that TMEM63B is expressed by subsets of kidney and lower urinary tract epithelial cells, which we hypothesize are sites of TMEM63B mechanosensation or osmosensation, or both. 10.14814/phy2.16043
The tomato calcium-permeable channel 4.1 (SlOSCA4.1) is a susceptibility factor for pepino mosaic virus. Plant biotechnology journal The hyperosmolality-gated calcium permeable channel 4.1 (OSCA4.1) belongs to an evolutionarily conserved small family of mechano-sensitive channels. OSCA members may represent key players in plant resistance to drought and to pathogen infection but are scarcely studied. After screening for resistance to pepino mosaic virus (PepMV) a collection of 1000 mutagenized tomato families, we identified a mutant showing no symptoms and reduced virus accumulation. Resistance was mapped to chromosome 2 between positions 46 309 531 to 47 044 163, where a missense mutation caused the putative truncation of the OSCA4.1 protein. A CRISPR/Cas9 slosca4.1 mutant was resistant to PepMV, but not to tobacco mosaic virus or potato virus X. Inoculation of mutant and wild type tomato protoplasts showed that resistance was expressed in single cells, suggesting a role for SlOSCA4.1 in early viral function(s); congruently, SlOSCA4.1 re-localized to structures reminiscent of viral replication complexes. We propose that SlOSCA4.1 contributes to the correct regulation of the Ca homeostasis necessary for optimal PepMV infection. PepMV is a pandemic virus that causes significant losses in tomato crops worldwide. In spite of its importance, no tomato-resistant varieties have been deployed yet; the mutant identified here has great potential to breed tomato varieties resistant to PepMV. 10.1111/pbi.14119
Overexpression of Osmosensitive Ca-Permeable Channel TMEM63B Promotes Migration in HEK293T Cells. Marques Marta C,Albuquerque Inês S,Vaz Sandra H,Bernardes Gonçalo J L Biochemistry The recent discovery of the osmosensitive calcium (Ca) channel OSCA has revealed the potential mechanism by which plant cells sense diverse stimuli. Osmosensory transporters and mechanosensitive channels can detect and respond to osmotic shifts that play an important role in active cell homeostasis. Members of the TMEM63 family of proteins are described as the closest homologues of OSCAs. Here, we characterize TMEM63B, a mammalian homologue of OSCAs, recently classified as mechanosensitive. In HEK293T cells, TMEM63B localizes to the plasma membrane and is associated with F-actin. This Ca-permeable channel specifically induces Ca influx across the membrane in response to extracellular Ca concentration and hyperosmolarity. In addition, overexpression of TMEM63B in HEK293T cells significantly enhanced cell migration and wound healing. The link between Ca osmosensitivity and cell migration might help to establish TMEM63B's pathogenesis, for example, in cancer in which it is frequently overexpressed. 10.1021/acs.biochem.9b00224
Structure of mechanically activated ion channel OSCA2.3 reveals mobile elements in the transmembrane domain. bioRxiv : the preprint server for biology Members of the OSCA/TMEM63 are mechanically activated ion channels and structures of some OSCA members have revealed the architecture of these channels and structural features that are potentially involved in mechanosensation. However, these structures are all in a similar state and information about the motion of different elements of the structure is limited, preventing a deeper understanding of how these channels work. Here, we used cryo-electron microscopy to determine high resolution structures of OSCA1.2 and OSCA2.3 in peptidiscs. The structure of OSCA1.2 resembles previous structures of the same protein in different environments. Yet, in OSCA2.3 the TM6a-TM7 linker constricts the pore on its cytoplasmic side, revealing conformational heterogeneity within the OSCA family. Furthermore, coevolutionary sequence analysis uncovered a conserved interaction between TM6a-TM7 linker and the Beam-Like Domain. Our results support the involvement of TM6a-TM7 in mechanosensation and potentially in the diverse response of OSCA channels to mechanical stimuli. 10.1101/2023.06.15.545135
Structure-guided mutagenesis of OSCAs reveals differential activation to mechanical stimuli. bioRxiv : the preprint server for biology The dimeric two-pore OSCA/TMEM63 family has recently been identified as mechanically activated ion channels. Previously, based on the unique features of the structure of OSCA1.2, we postulated the potential involvement of several structural elements in sensing membrane tension. Interestingly, while OSCA1, 2, and 3 clades are activated by membrane stretch in cell-attached patches (i.e., they are stretch-activated channels), they differ in their ability to transduce membrane deformation induced by a blunt probe (poking). In an effort to understand the domains contributing to mechanical signal transduction, we used cryo-electron microscopy to solve the structure of (At) OSCA3.1, which, unlike AtOSCA1.2, only produced stretch- but not poke-activated currents in our initial characterization. Mutagenesis and electrophysiological assessment of conserved and divergent putative mechanosensitive features of OSCA1.2 reveal a selective disruption of the macroscopic currents elicited by poking without considerable effects on stretch-activated currents (SAC). Our results support the involvement of the amphipathic helix and lipid-interacting residues in the membrane fenestration in the response to poking. Our findings position these two structural elements as potential sources of functional diversity within the family. 10.1101/2023.10.03.560740
Cryo-EM structure of the mechanically activated ion channel OSCA1.2. eLife Mechanically activated ion channels underlie touch, hearing, shear-stress sensing, and response to turgor pressure. OSCA/TMEM63s are a newly-identified family of eukaryotic mechanically activated ion channels opened by membrane tension. The structural underpinnings of OSCA/TMEM63 function are not explored. Here, we elucidate high resolution cryo-electron microscopy structures of OSCA1.2, revealing a dimeric architecture containing eleven transmembrane helices per subunit and surprising topological similarities to TMEM16 proteins. We locate the ion permeation pathway within each subunit by demonstrating that a conserved acidic residue is a determinant of channel conductance. Molecular dynamics simulations reveal membrane interactions, suggesting the role of lipids in OSCA1.2 gating. These results lay a foundation to decipher how the structural organization of OSCA/TMEM63 is suited for their roles as MA ion channels. 10.7554/eLife.41845
Evolution of osmosensing OSCA1 Ca channel family coincident with plant transition from water to land. The plant genome Water is crucial to plant growth, development, and environmental adaptation. Water stress triggers cytosolic Ca ([Ca ] ) increases, and the osmosensor OSCA1 (REDUCED-HYPEROSMOLALITY-INDUCED-[Ca ] -INCREASE 1), a member of the OSCA family, perceives the initial water stress and governs its downstream responses. OSCA homologs exist in eukaryotes and largely radiate in higher plants. However, it is enigmatic whether the OSCA family is crucial for plant evolution from aqueous to terrestrial environments and for the subsequent adaptation on land. Here, we carried out the first phylogenetic and molecular evolutionary analyses of the OSCA family. The family originated and diversified during the early evolution of protists, and three more lineages were established (a) in plants, (b) in fungi, and (c) in a complex clade of several major eukaryotic lineages. The chlorophyte algal cluster is directly basal to streptophyte-specific Clades 1-3, consistent with plant transition from water to land. The Clades 1-3 present different gene expansion pattern and together with previous functional analysis of OSCAs reveal that they probably have evolved diverse functions in respond to various mechanical stresses during the independent evolution of land plant clades. Moreover, variable selection pressures on different land plant lineages were explored. OSCAs in early land plants (mosses and lycophytes) were under decelerated evolution, whereas OSCAs in seed plants showed accelerated evolution. Together, we hypothesize OSCAs have evolved to sense water stress in the ancestor of euphyllophytes, which occupies typical leaves, typical roots, and phloem tissues, all of which require osmosensors to maintain water balance and food conduction through plant bodies. 10.1002/tpg2.20198
Structure of the hyperosmolality-gated calcium-permeable channel OSCA1.2. Liu Xin,Wang Jiawei,Sun Linfeng Nature communications In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade initiated by cytosolic calcium concentration elevation. Members of the OSCA family in Arabidopsis thaliana, identified as the hyperosmolality-gated calcium-permeable channels, have been suggested to play a key role during the initial phase of hyperosmotic stress response. Here, we report the atomic structure of Arabidopsis OSCA1.2 determined by single-particle cryo-electron microscopy. It contains 11 transmembrane helices and forms a homodimer. It is in an inactivated state, and the pore-lining residues are clearly identified. Its cytosolic domain contains a RNA recognition motif and two unique long helices. The linker between these two helices forms an anchor in the lipid bilayer and may be essential to osmosensing. The structure of AtOSCA1.2 serves as a platform for the study of the mechanism underlying osmotic stress responses and mechanosensing. 10.1038/s41467-018-07564-5
Calcium Channels, OST1 and Stomatal Defence: Current Status and Beyond. Cells Stomatal immunity is regulated by pathogen-associated molecular patterns (PAMPs)- and abscisic acid (ABA)-triggered signalling in different ways. Cytoplasmic Ca signature in the guard cells plays a vital function in stomatal immunity, but the mechanism of Ca import is unknown. It has been very recently established that the hyperosmolality-gated calcium-permeable channels (OSCAs) and cyclic nucleotide-gated channels (CNGCs) are responsible for the influx of Ca in the cytoplasm, which are activated after BIK1-mediated phosphorylation and ABA interaction during PAMPs- and ABA-triggered stomatal immunity in plants, respectively. Further, ABA-triggered OPEN STOMATA1 (OST1) causes the disassembly of microtubules in the guard cells besides activation of S-type anion channels (SLAC1) for the efflux of cytoplasmic anions that leads to stomata closure. 10.3390/cells12010127
Between Stress and Response: Function and Localization of Mechanosensitive Ca Channels in Herbaceous and Perennial Plants. International journal of molecular sciences Over the past three decades, how plants sense and respond to mechanical stress has become a flourishing field of research. The pivotal role of mechanosensing in organogenesis and acclimation was demonstrated in various plants, and links are emerging between gene regulatory networks and physical forces exerted on tissues. However, how plant cells convert physical signals into chemical signals remains unclear. Numerous studies have focused on the role played by mechanosensitive (MS) calcium ion channels MCA, Piezo and OSCA. To complement these data, we combined data mining and visualization approaches to compare the tissue-specific expression of these genes, taking advantage of recent single-cell RNA-sequencing data obtained in the root apex and the stem of and the stem. These analyses raise questions about the relationships between the localization of MS channels and the localization of stress and responses. Such tissue-specific expression studies could help to elucidate the functions of MS channels. Finally, we stress the need for a better understanding of such mechanisms in trees, which are facing mechanical challenges of much higher magnitudes and over much longer time scales than herbaceous plants, and we mention practical applications of plant responsiveness to mechanical stress in agriculture and forestry. 10.3390/ijms222011043
Ca to the rescue - Cachannels and signaling in plant immunity. Moeder Wolfgang,Phan Van,Yoshioka Keiko Plant science : an international journal of experimental plant biology Ca is a universal second messenger in many signaling pathways in all eukaryotes including plants. Transient changes in [Ca]cyt are rapidly generated upon a diverse range of stimuli such as drought, heat, wounding, and biotic stresses (infection by pathogenic and symbiotic microorganisms), as well as developmental cues. It has been known for a while that [Ca]cyt transient signals play crucial roles to activate plant immunity and recently significant progresses have been made in this research field. However the identity and regulation of ion channels that are involved in defense related Ca signals are still enigmatic. Members of two ligand gated ion channel families, glutamate receptor-like channels (GLRs) and cyclic nucleotide-gated channels (CNGCs) have been implicated in immune responses; nevertheless more precise data to understand their direct involvement in the creation of Ca signals during immune responses is necessary. Furthermore, the study of other ion channel groups is also required to understand the whole picture of the intra- and inter-cellular Ca signalling network. In this review we summarize Ca signals in plant immunity from an ion channel point of view and discuss future challenges in this exciting research field. 10.1016/j.plantsci.2018.04.012
OsOSCA1.1 Mediates Hyperosmolality and Salt Stress Sensing in . Biology OSCA () is a family of mechanosensitive calcium-permeable channels that play a role in osmosensing and stomatal immunity in plants. has 11 genes; some of these were shown to complement hyperosmolality-induced [Ca] increases (OICI), salt stress-induced [Ca] increases (SICI), and the associated growth phenotype in the mutant . However, their biological functions in rice remain unclear. In this paper, we found that OsOSCA1.1 mediates OICI and SICI in rice roots, which are critical for stomatal closure, plant survival, and gene expression in shoots, in response to hyperosmolality and the salt stress treatment of roots. Compared with wild-type (Zhonghua11, ZH11) plants, OICI and SICI were abolished in the roots of 10-day-old seedlings, in response to treatment with 250 mM of sorbitol and 100 mM of NaCl, respectively. Moreover, hyperosmolality- and salt stress-induced stomatal closure were also disrupted in a 30-day-old mutant, resulting in lower stomatal resistance and survival rates than that in ZH11. However, overexpression of in complemented stomatal movement and survival, in response to hyperosmolality and salt stress. The transcriptomic analysis further revealed the following three types of OsOSCA1.1-regulated genes in the shoots: 2416 sorbitol-responsive, 2349 NaCl-responsive and 1844 common osmotic stress-responsive genes after treated with 250 mM of sorbitol and 125 mM NaCl of in 30-day-old rice roots for 24 h. The Gene Ontology enrichment analysis showed that these OsOSCA1.1-regulated genes were relatively enriched in transcription regulation, hormone response, and phosphorylation terms of the biological processes category, which is consistent with the -regulatory elements ABRE, ARE, MYB and MYC binding motifs that were overrepresented in 2000-bp promoter regions of these OsOSCA1.1-regulated genes. These results indicate that OsOSCA-mediated calcium signaling specifically regulates gene expression, in response to drought and salt stress in rice. 10.3390/biology11050678
Sensing of membrane tensions: the pleiotropic functions of OSCA/TMEM63 mechanosensitive ion channels. Journal of genetics and genomics = Yi chuan xue bao 10.1016/j.jgg.2024.02.002
Genome-wide survey and expression analysis of the OSCA gene family in rice. BMC plant biology BACKGROUND:Reception of and response to exogenous and endogenous osmotic changes is important to sustain plant growth and development, as well as reproductive formation. Hyperosmolality-gated calcium-permeable channels (OSCA) were first characterised as an osmosensor in Arabidopsis and are involved in the perception of extracellular changes to trigger hyperosmolality-induced [Ca(2+)]i increases (OICI). To explore the potential biological functions of OSCAs in rice, we performed a bioinformatics and expression analysis of the OsOSCA gene family. RESULTS:A total of 11 OsOSCA genes were identified from the genome database of Oryza sativa L. Japonica. Based on their sequence composition and phylogenetic relationship, the OsOSCA family was classified into four clades. Gene and protein structure analysis indicated that the 11 OsOSCAs shared similar structures with their homologs in Oryza sativa L. ssp. Indica, Oryza glaberrima, and Oryza brachyantha. Multiple sequence alignment analysis revealed a conserved DUF221 domain in these members, in which the first three TMs were conserved, while the others were not. The expression profiles of OsOSCA genes were analysed at different stages of vegetative growth, reproductive development, and under osmotic-associated abiotic stresses. We found that four and six OsOSCA genes showed a clear correlation between the expression profile and osmotic changes during caryopsis development and seed imbibition, respectively. Orchestrated transcription of three OsOSCAs was strongly associated with the circadian clock. Moreover, osmotic-related abiotic stress differentially induced the expression of 10 genes. CONCLUSION:The entire OSCA family is characterised by the presence of a conserved DUF221 domain, which functions as an osmotic-sensing calcium channel. The phylogenetic tree of OSCA genes showed that two subspecies of cultivated rice, Oryza sativa L. ssp. Japonica and Oryza sativa L. ssp. Indica, are more closely related than wild rice Oryza glaberrima, while Oryza brachyantha was less closely related. OsOSCA expression is organ- and tissue-specific and regulated by different osmotic-related abiotic stresses in rice. These findings will facilitate further research in this gene family and provide potential target genes for generation of genetically modified osmotic-stress-resistant plants. 10.1186/s12870-015-0653-8
Genome-wide investigation and expression analysis of gene family in response to abiotic stress in alfalfa. Frontiers in plant science Alfalfa is an excellent leguminous forage crop that is widely cultivated worldwide, but its yield and quality are often affected by drought and soil salinization. Hyperosmolality-gated calcium-permeable channel (OSCA) proteins are hyperosmotic calcium ion (Ca) receptors that play an essential role in regulating plant growth, development, and abiotic stress responses. However, no systematic analysis of the gene family has been conducted in alfalfa. In this study, a total of 14 genes were identified from the alfalfa genome and classified into three groups based on their sequence composition and phylogenetic relationships. Gene structure, conserved motifs and functional domain prediction showed that all genes had the same functional domain DUF221. -acting element analysis showed that genes had many -regulatory elements in response to abiotic or biotic stresses and hormones. Tissue expression pattern analysis demonstrated that the genes had tissue-specific expression; for example, was only expressed in roots and leaves but not in stem and petiole tissues. Furthermore, RT-qPCR results indicated that the expression of genes was induced by abiotic stress (drought and salt) and hormones (JA, SA, and ABA). In particular, the expression levels of , , and were significantly increased under drought and salt stress, and , , and genes exhibited significant upregulation under plant hormone treatments, indicating that these genes play a positive role in drought, salt and hormone responses. Subcellular localization results showed that the MsOSCA3 protein was localized on the plasma membrane. This study provides a basis for understanding the biological information and further functional analysis of the gene family and provides candidate genes for stress resistance breeding in alfalfa. 10.3389/fpls.2023.1285488
Systematic Analysis of the Maize Genes Revealing Family Members Involved in Osmotic Stress and Confers Enhanced Drought Tolerance in Transgenic . Cao Liru,Zhang Pengyu,Lu Xiaomin,Wang Guorui,Wang Zhenhua,Zhang Qianjin,Zhang Xin,Wei Xin,Mei Fujian,Wei Li,Wang Tongchao International journal of molecular sciences OSCAs are hyperosmolality-gated calcium-permeable channel proteins. In this study, two co-expression modules, which are strongly associated with maize proline content, were screened by weighted correlation network analysis, including three ZmOSCA family members. Phylogenetic and protein domain analyses revealed that 12 ZmOSCA members were classified into four classes, which all contained DUF221 domain. The promoter region contained multiple core elements responsive to abiotic stresses and hormones. Colinear analysis revealed that had diversified prior to maize divergence. Most responded positively to ABA, PEG, and NaCl treatments. and were up-regulated by more than 200-fold under the three stresses, and showed significant positive correlations with proline content. Yeast two-hybrid and bimolecular fluorescence complementation indicated that ZmOSCA2.3 and ZmOSCA2.4 proteins interacted with ZmEREB198. Over-expression of in remarkably improved drought resistance. Moreover, over-expression of enhanced the expression of drought tolerance-associated genes and reduced the expression of senescence-associated genes. We also found that perhaps was regulated by miR5054.The results provide a high-quality molecular resource for selecting resistant breeding, and lay a foundation for elucidating regulatory mechanism of under abiotic stresses. 10.3390/ijms21010351
Genome-wide characterization and comparative analysis of the OSCA gene family and identification of its potential stress-responsive members in legumes. Scientific reports Cicer arietinum, Cajanus cajan, Vigna radiata, and Phaseolus vulgaris are economically important legume crops with high nutritional value. They are negatively impacted globally by different biotic and abiotic stresses. Hyperosmolality-gated calcium-permeable channels (OSCA) have been characterized as osmosensors in Arabidopsis thaliana but have not previously reported in legumes. This study provides a genome-wide identification, characterization, and comparative analysis of OSCA genes in legumes. Our study identified and characterized 13 OSCA genes in C. cajan, V. radiata, P. vulgaris, and 12 in C. arietinum, classified into four distinct clades. We found evidence to suggest that the OSCAs might be involved in the interaction between hormone signalling pathways and stress signalling pathways. Furthermore, they play a major role in plant growth and development. The expression levels of the OSCAs vary under different stress conditions in a tissue-specific manner. Our study can be used to develop a detailed understanding of stress regulatory mechanisms of the OSCA gene family in legumes. 10.1038/s41598-023-33226-8
Mammalian Mechanoelectrical Transduction: Structure and Function of Force-Gated Ion Channels. Douguet Dominique,Honoré Eric Cell The conversion of force into an electrical cellular signal is mediated by the opening of different types of mechanosensitive ion channels (MSCs), including TREK/TRAAK K channels, Piezo1/2, TMEM63/OSCA, and TMC1/2. Mechanoelectrical transduction plays a key role in hearing, balance, touch, and proprioception and is also implicated in the autonomic regulation of blood pressure and breathing. Thus, dysfunction of MSCs is associated with a variety of inherited and acquired disease states. Significant progress has recently been made in identifying these channels, solving their structure, and understanding the gating of both hyperpolarizing and depolarizing MSCs. Besides prototypical activation by membrane tension, additional gating mechanisms involving channel curvature and/or tethered elements are at play. 10.1016/j.cell.2019.08.049
TMEM16 and TMEM63/OSCA proteins share a conserved potential to permeate ions and phospholipids. bioRxiv : the preprint server for biology The calcium-activated TMEM16 proteins and the mechanosensitive/osmolarity-activated OSCA/TMEM63 proteins belong to the Transmembrane Channel/Scramblase (TCS) superfamily. Within the superfamily, OSCA/TMEM63 proteins, as well as TMEM16A and TMEM16B, likely function solely as ion channels. However, the remaining TMEM16 members, including TMEM16F, maintain an additional function as scramblases, rapidly exchanging phospholipids between leaflets of the membrane. Although recent studies have advanced our understanding of TCS structure-function relationships, the molecular determinants of TCS ion and lipid permeation remain unclear. Here we show that single lysine mutations in transmembrane helix (TM) 4 allow non-scrambling TCS members to permeate phospholipids. This study highlights the key role of TM 4 in controlling TCS ion and lipid permeation and offers novel insights into the evolution of the TCS superfamily, suggesting that, like TMEM16s, the OSCA/TMEM63 family maintains a conserved potential to permeate ions and phospholipids. 10.1101/2024.02.04.578431
A member of the OSCA/TMEM63 family of mechanosensitive calcium channels participates in cell wall integrity maintenance in Aspergillus nidulans. Fungal genetics and biology : FG & B The calF7 mutation in Aspergillus nidulans causes hypersensitivity to the cell wall compromising agents Calcofluor White (CFW) and Congo Red. In this research we demonstrate that the calF7 mutation resides in gene AN2880, encoding a predicted member of the OSCA/TMEM63 family of transmembrane glycoproteins. Those members of the family whose physiological functions have been investigated have been shown to act as mechanosensitive calcium transport channels. Deletion of AN2880 replicates the CFW hypersensitivity phenotype. Separately, we show that CFW hypersensitivity of calF deletion strains can be overcome by inclusion of elevated levels of extracellular calcium ions in the growth medium, and, correspondingly, wild type strains grown in media deficient in calcium ions are no longer resistant to CFW. These observations support a model in which accommodation to at least some forms of cell wall stress is mediated by a calcium ion signaling system in which the AN2880 gene product plays a role. The genetic lesion in calF7 is predicted to result in a glycine-to-arginine substitution at position 638 of the 945-residue CalF protein in a region of the RSN1_7TM domain that is highly conserved amongst filamentous fungi. Homology modeling predicts that the consequence of a G638R substitution is to structurally occlude the principal conductance pore in the protein. GFP-tagged wild type CalF localizes principally to the Spitzenkörper and the plasma membrane at growing tips and forming septa. However, both septation and hyphal morphology appear to be normal in calF7 and AN2880 deletion strains, indicating that any role played by CalF in normal hyphal growth and cytokinesis is dispensable. 10.1016/j.fgb.2023.103842
TMEM63 mechanosensitive ion channels: Activation mechanisms, biological functions and human genetic disorders. Biochemical and biophysical research communications The transmembrane 63 (TMEM63) family of proteins are originally identified as homologs of the osmosensitive calcium-permeable (OSCA) channels in plants. Mechanosensitivity of OSCA and TMEM63 proteins are recently demonstrated in addition to their proposed activation mechanism by hyper/hypo-osmolarity. TMEM63 proteins exist in all animals, with a single member in Drosophila (TMEM63) and three members in mammals (TMEM63 A/B/C). In humans, monoallelic variants of TMEM63A have been reported to cause transient hypomyelination during infancy, or severe hypomyelination and global developmental delay. Heterozygous variants of TMEM63B are found in patients with intellectual disability and abnormal motor function and brain morphology. Biallelic variants of TMEM63C are associated with hereditary spastic paraplegias accompanied by mild or no intellectual disability. Physiological functions of TMEM63 proteins clearly recognized so far include detecting food grittiness and environmental humidity in Drosophila, and supporting hearing in mice by regulating survival of cochlear hair cells. In this review, we summarize current knowledge about the activation mechanisms and biological functions of TMEM63 channels, and provide a concise reference for researchers interested in investigating more physiological and pathogenic roles of this family of proteins with ubiquitous expression in the body. 10.1016/j.bbrc.2023.10.043
Genome-wide analysis of hyperosmolality-gated calcium-permeable channel (OSCA) family members and their involvement in various osmotic stresses in Brassica napus. Gene Plant hyperosmolality-gated calcium-permeable channel (OSCA) is a calcium permeable cation channel that responds to hyperosmotic stress and plays a pivotal role in plant growth, development and stress response. Through a genome-wide survey, 41 OSCA genes were identified from the genome of Brassica napus. The OSCA family genes were unevenly distributed over 14 chromosomes of B. napus and phylogenetic analysis separated the OSCA family into four clades. Motif analyses indicated that OSCA proteins in the same clade were highly conserved and the protein conserved motifs shared similar composition patterns. The OSCA promoter regions contained many hormone-related elements and stress response elements. Gene duplication analysis elucidated that WGD/segmental duplication was the main driving force for the expansion of OSCA genes during evolution and these genes mainly underwent purifying selection. RNA-seq and qRT-PCR analysis of different tissues showed that OSCA genes are expressed and function mainly in the root. Among these genes, BnOSCA3.1a and BnOSCA3.1c had relatively high expression levels under osmotic stresses and cold stress and were highly expressed in different tissues. Protein interaction network analysis showed that a total of 5802 proteins might interact with OSCAs in B. napus, while KEGG/GO enrichment analysis indicated that OSCAs and their interacting proteins were mainly involved in plant response to abiotic stress. This systematic analysis of the OSCAs in B. napus identified gene structures, evolutionary features, expression patterns and related biological processes. These findings will facilitate further functional and evolutionary analysis of OSCAs in B. napus for breeding of osmotic-stress-resistant plants. 10.1016/j.gene.2022.147137
Functional analysis of rice OSCA genes overexpressed in the arabidopsis osca1 mutant due to drought and salt stresses. Transgenic research Drought and salt are two major abiotic stresses that severely impact plant growth and development, as well as crop production. A previous study showed that OsOSCA1.4, one of eleven rice OSCAs (OsOSCAs), complements hyperosmolality-induced [Ca] increases (OICI), salt stress-induced [Ca] increases (SICI) and the associated growth phenotype in Arabidopsis osca1 (reduced hyperosmolality-induced [Ca] increase 1). In this study, Except for OsOSCA2.3 and OsOSCA4.1, we generated independent transgenic lines overexpressing eight other OsOSCAs in the osca1 to explore their functions in osmotic Ca signalling, stomatal movement, leaf water loss, and root growth in response to hyperosmolality and salt stress. Similar to OsOSCA1.4, overexpression of OsOSCA1.1 or OsOSCA2.2 in osca1 complemented OICI and SICI, as well as stomatal closure and root growth in response to hyperosmolality and salt stress treatments, and drought-related leaf water loss. In addition, overexpression of OsOSCA1.2, OsOSCA1.3 or OsOSCA2.1 in osca1 restored OICI and SICI, whereas overexpression of OsOSCA2.5 or OsOSCA3.1 did not. Moreover, osca1 overexpressing these five OsOSCAs exhibited various abiotic stress-associated growth phenotypes. However, overexpression of OsOSCA2.4 did not have any of these effects. These results indicated that multiple members of the OsOSCA family have redundant functions in osmotic sensing and diverse roles in stress adaption. 10.1007/s11248-021-00270-x
Genome-wide analysis of OSCA gene family members in Vigna radiata and their involvement in the osmotic response. BMC plant biology BACKGROUND:Mung bean (Vigna radiata) is a warm-season legume crop and belongs to the papilionoid subfamily of the Fabaceae family. China is the leading producer of mung bean in the world. Mung bean has significant economic and health benefits and is a promising species with broad adaptation ability and high tolerance to environmental stresses. OSCA (hyperosmolality-gated calcium-permeable channel) gene family members play an important role in the modulation of hypertonic stress, such as drought and salinity. However, genome-wide analysis of the OSCA gene family has not been conducted in mung bean. RESULTS:We identified a total of 13 OSCA genes in the mung bean genome and named them according to their homology with AtOSCAs. All the OSCAs were phylogenetically split into four clades. Phylogenetic relationship and synteny analyses showed that the VrOSCAs in mung bean and soybean shared a relatively conserved evolutionary history. In addition, three duplicated VrOSCA gene pairs were identified, and the duplicated VrOSCAs gene pairs mainly underwent purifying selection pressure during evolution. Protein domain, motif and transmembrane analyses indicated that most of the VrOSCAs shared similar structures with their homologs. The expression pattern showed that except for VrOSCA2.1, the other 12 VrOSCAs were upregulated under treatment with ABA, PEG and NaCl, among which VrOSCA1.4 showed the largest increased expression levels. The duplicated genes VrOSCA2.1/VrOSCA2.2 showed divergent expression, which might have resulted in functionalization during subsequent evolution. The expression profiles under ABA, PEG and NaCl stress revealed a functional divergence of VrOSCA genes, which agreed with the analysis of cis-acting regulatory elements in the promoter regions of VrOSCA genes. CONCLUSIONS:Collectively, the study provided a systematic analysis of the VrOSCA gene family in mung bean. Our results establish an important foundation for functional and evolutionary analysis of VrOSCAs and identify genes for further investigation of their ability to confer abiotic stress tolerance in mung bean. 10.1186/s12870-021-03184-2
Genome-wide analysis of maize family members and their involvement in drought stress. Ding Shuangcheng,Feng Xin,Du Hewei,Wang Hongwei PeerJ BACKGROUND:Worldwide cultivation of maize is often impacted negatively by drought stress. Hyperosmolality-gated calcium-permeable channels (OSCA) have been characterized as osmosensors in . However, the involvement of members of the maize () gene family in response to drought stress is unknown. It is furthermore unclear which gene plays a major role in genetic improvement of drought tolerance in Maize. METHODS:We predicted the protein domain structure and transmembrane regions by using the NCBI Conserved Domain Database database and TMHMM server separately. The phylogeny tree was built by Mega7. We used the mixed linear model in TASSEL to perform the family-based association analysis. RESULTS:In this report, 12 genes were uncovered in the maize genome by a genome-wide survey and analyzed systematically to reveal their synteny and phylogenetic relationship with the genomes of rice, maize, and sorghum. These analyses indicated a relatively conserved evolutionary history of the gene family. Protein domain and transmembrane analysis indicated that most of the 12 ZmOSCAs shared similar structures with their homologs. The result of differential expression analysis under drought at various stages, as well as the expression profiles in 15 tissues, revealed a functional divergence of genes. Notably, the expression level of being up-regulated in both seedlings and adult leaves. Notably, the association analysis between genetic variations in these genes and drought tolerance was detected. Significant associations between genetic variation in and drought tolerance were found at the seedling stage. Our report provides a detailed analysis of the in the maize genome. These findings will contribute to future studies on the functional characterization of ZmOSCA proteins in response to water deficit stress, as well as understanding the mechanism of genetic variation in drought tolerance in maize. 10.7717/peerj.6765
Genomewide identification and analysis of the gene family in barley ( L.). Journal of genetics The hyperosmolality-gated calcium-permeable channels (OSCA) are considered to be osmotic sensors that play an important role in the early stages of hyperosmotic stress response. We analysed the physicochemical properties, chromosome distribution, phylogeny, gene structure and expression pattern of the gene family in barley, and investigated the expression of genes in barley under drought stress by quantitative real-time polymerase chain reaction (qRT-PCR). Finally, 14 members of the gene family were identified from barley, all containing the RSN1_7TM domain and often accompanied by the RSN1_TM and PHM7_cyt domains. According to the phylogenetic relationship, they were divided into four subgroups, and each with similar gene structures. Two types of duplicate events in the genes family evolved under the effect of purification selection. By analysing the -acting elements in the HvOSCA promoter, it was speculated that the barley gene family is involved in the regulation of multiple signalling pathways. The expression of genes in barley tissues and their relative expression under drought stress revealed that the gene family plays a role in plant organ differentiation, growth and development and coping with abiotic stress. These results provide new valuable information for the functional analysis of genes and the genetic improvement of barley, and provide an important reference for follow-up research.
Systematic Characterization of the Family Members in Soybean and Validation of Their Functions in Osmotic Stress. International journal of molecular sciences Since we discovered OSCA1, a hyperosmolarity-gated calcium-permeable channel that acted as an osmosensor in , the family has been identified genome-wide in several crops, but only a few members' functions have been experimentally demonstrated. Osmotic stress seriously restricts the yield and quality of soybean. Therefore, it is essential to decipher the molecular mechanism of how soybean responds to osmotic stress. Here, we first systematically studied and experimentally demonstrated the role of family members in the osmotic sensing of soybean. Phylogenetic relationships, gene structures, protein domains and structures analysis revealed that 20 members were divided into four clades, of which members in the same cluster may have more similar functions. In addition, members in clusters III and IV may be functionally redundant and diverged from those in clusters I and II. Based on the spatiotemporal expression patterns, , , , and were extremely low expressed or possible pseudogenes. The remaining 16 genes were heterologously overexpressed in an mutant, to explore their functions. Subcellular localization showed that most GmOSCA members could localize to the plasma membrane (PM). Among 16 genes, only overexpressing , , , , and in cluster I could fully complement the reduced hyperosmolality-induced [Ca] increase (OICI) in . The expression profiles of genes against osmotic stress demonstrated that most genes, especially , , , , , , and , strongly responded to osmotic stress. Moreover, overexpression of , , , , , , and rescued the drought-hypersensitive phenotype of . Our findings provide important clues for further studies of -mediated calcium signaling in the osmotic sensing of soybean and contribute to improving soybean drought tolerance through genetic engineering and molecular breeding. 10.3390/ijms231810570
Preliminary Expression Analysis of the Gene Family in Maize and Their Involvement in Temperature Stress. International journal of molecular sciences Hyperosmolality-gated calcium-permeable channels (OSCA) are characterized as an osmosensor in plants; they are able to recognize and respond to exogenous and endogenous osmotic changes, and play a vital role in plant growth and adaptability to environmental stress. To explore the potential biological functions of OSCAs in maize, we performed a bioinformatics and expression analysis of the gene family. Using bioinformatics methods, we identified twelve genes from the genome database of maize. According to their sequence composition and phylogenetic relationship, the maize family was classified into four groups (Ⅰ, Ⅱ, Ⅲ, and Ⅳ). Multiple sequence alignment analysis revealed a conserved DUF221 domain in these members. We modeled the calcium binding sites of four OSCA families using the autodocking technique. The expression profiles of genes were analyzed in different tissues and under diverse abiotic stresses such as drought, salt, high temperature, and chilling using quantitative real-time PCR (qRT-PCR). We found that the expression of twelve genes is variant in different tissues of maize. Furthermore, abiotic stresses such as drought, salt, high temperature, and chilling differentially induced the expression of twelve genes. We chose OSCA2.2 and OSCA2.3, which responded most strongly to temperature stress, for prediction of protein interactions. We modeled the calcium binding sites of four OSCA families using autodocking tools, obtaining a number of new results. These results are helpful in understanding the function of the plant gene family for study of the molecular mechanism of plant osmotic stress and response, as well as exploration of the interaction between osmotic stress, high-temperature stress, and low-temperature stress signal transduction mechanisms. As such, they can provide a theoretical basis for crop breeding. 10.3390/ijms232113658
Structure of the mechanosensitive OSCA channels. Zhang Mingfeng,Wang Dali,Kang Yunlu,Wu Jing-Xiang,Yao Fuqiang,Pan Chengfang,Yan Zhiqiang,Song Chen,Chen Lei Nature structural & molecular biology Mechanosensitive ion channels convert mechanical stimuli into a flow of ions. These channels are widely distributed from bacteria to higher plants and humans, and are involved in many crucial physiological processes. Here we show that two members of the OSCA protein family in Arabidopsis thaliana, namely AtOSCA1.1 and AtOSCA3.1, belong to a new class of mechanosensitive ion channels. We solve the structure of the AtOSCA1.1 channel at 3.5-Å resolution and AtOSCA3.1 at 4.8-Å resolution by cryo-electron microscopy. OSCA channels are symmetric dimers that are mediated by cytosolic inter-subunit interactions. Strikingly, they have structural similarity to the mammalian TMEM16 family proteins. Our structural analysis accompanied with electrophysiological studies identifies the ion permeation pathway within each subunit and suggests a conformational change model for activation. 10.1038/s41594-018-0117-6
OSCA/TMEM63 are an Evolutionarily Conserved Family of Mechanically Activated Ion Channels. eLife Mechanically activated (MA) ion channels convert physical forces into electrical signals, and are essential for eukaryotic physiology. Despite their importance, few bona-fide MA channels have been described in plants and animals. Here, we show that various members of the OSCA and TMEM63 family of proteins from plants, flies, and mammals confer mechanosensitivity to naïve cells. We conclusively demonstrate that OSCA1.2, one of the OSCA proteins, is an inherently mechanosensitive, pore-forming ion channel. Our results suggest that OSCA/TMEM63 proteins are the largest family of MA ion channels identified, and are conserved across eukaryotes. Our findings will enable studies to gain deep insight into molecular mechanisms of MA channel gating, and will facilitate a better understanding of mechanosensory processes in vivo across plants and animals. 10.7554/eLife.41844
Evolutionary analysis of the OSCA gene family in sunflower () and expression analysis under NaCl stress. PeerJ Hyperosmolality-gated calcium-permeable channels (OSCA) are Ca nonselective cation channels that contain the calcium-dependent DUF221 domain, which plays an important role in plant response to stress and growth. However, the OSCA gene has not been fully identified and analyzed in sunflowers. In this study, we comprehensively analyzed the number, structure, collinearity, and phylogeny of the OSCA gene family in the sunflower, six Compositae species ( and ), and six other plants (soybean, , rice, grape, and maize). The expression of the sunflower OSCA gene in nine different tissues, six different hormones, and NaCl stress conditions were analyzed based on transcriptome data and qRT-PCR. A total of 15 OSCA proteins, distributed on 10 chromosomes, were identified in the sunflower, and all of them were located in the endoplasmic reticulum. Using the phylogenetic tree, collinearity, gene structure, and motif analysis of the six Compositae species and six other plants, we found that the sunflower OSCA protein had only three subfamilies and lacked the Group 4 subfamily, which is conserved in the evolution of Compositae and subject to purification selection. The OSCA gene structure and motif analysis of the sunflower and six Compositae showed that there was a positive correlation between the number of motifs of most genes and the length of the gene, different subfamilies had different motifs, and the Group 4 subfamily had the smallest number of genes and the simplest gene structure. RNA-seq and qRT-PCR analysis showed that the expression levels of most OSCA genes in the sunflower changed to varying degrees under salt stress, and and were the most important in the sunflower's response to salt stress. The coexpression network of the sunflower genes under salt stress was constructed based on weighted gene co-expression network analysis (WGCNA). In conclusion, our findings suggest that the OSCA gene family is conserved during the sunflower's evolution and plays an important role in salt tolerance. These results will deepen our understanding of the evolutionary relationship of the sunflower OSCA gene family and provide a basis for their functional studies under salt stress. 10.7717/peerj.15089
Identification of OSCA gene family in Solanum habrochaites and its function analysis under stress. BMC genomics BACKGROUND:OSCA (hyperosmolality-gated calcium-permeable channel) is a calcium permeable cation channel protein that plays an important role in regulating plant signal transduction. It is involved in sensing changes in extracellular osmotic potential and an increase in Ca concentration. S. habrochaites is a good genetic material for crop improvement against cold, late blight, planthopper and other diseases. Till date, there is no report on OSCA in S. habrochaites. Thus, in this study, we performed a genome-wide screen to identify OSCA genes in S. habrochaites and characterized their responses to biotic and abiotic stresses. RESULTS:A total of 11 ShOSCA genes distributed on 8 chromosomes were identified. Subcellular localization analysis showed that all members of ShOSCA localized on the plasma membrane and contained multiple stress-related cis acting elements. We observed that genome-wide duplication (WGD) occurred in the genetic evolution of ShOSCA5 (Solhab04g250600) and ShOSCA11 (Solhab12g051500). In addition, repeat events play an important role in the expansion of OSCA gene family. OSCA gene family of S. habrochaites used the time lines of expression studies by qRT-PCR, do indicate OSCAs responded to biotic stress (Botrytis cinerea) and abiotic stress (drought, low temperature and abscisic acid (ABA)). Among them, the expression of ShOSCAs changed significantly under four stresses. The resistance of silencing ShOSCA3 plants to the four stresses was reduced. CONCLUSION:This study identified the OSCA gene family of S. habrochaites for the first time and analyzed ShOSCA3 has stronger resistance to low temperature, ABA and Botrytis cinerea stress. This study provides a theoretical basis for clarifying the biological function of OSCA, and lays a foundation for tomato crop improvement. 10.1186/s12864-022-08675-6
Genes in Bread Wheat: Molecular Characterization, Expression Profiling, and Interaction Analyses Indicated Their Diverse Roles during Development and Stress Response. International journal of molecular sciences The hyperosmolality-gated calcium-permeable channels (OSCA) are pore-forming transmembrane proteins that function as osmosensors during various plant developmental processes and stress responses. In our analysis, through in silico approaches, a total of 42 genes are identified in the genome. A phylogenetic analysis reveals the close clustering of the OSCA proteins of , , and in all the clades, suggesting their origin before the divergence of dicots and monocots. Furthermore, evolutionary analyses suggest the role of segmental and tandem duplication events (Des) and purifying selection pressure in the expansion of the gene family in . Expression profiling in various tissue developmental stages and under abiotic and biotic stress treatments reveals the probable functioning of genes in plant development and the stress response in . In addition, protein-protein and protein-chemical interactions reveal that OSCA proteins might play a putative role in Ca-mediated developmental processes and adaptive responses. The miRNA interaction analysis strengthens the evidence for their functioning in various biological processes and stress-induced signaling cascades. The current study could provide a foundation for the functional characterization of genes in future studies. 10.3390/ijms232314867
A mechanical-coupling mechanism in OSCA/TMEM63 channel mechanosensitivity. Nature communications Mechanosensitive (MS) ion channels are a ubiquitous type of molecular force sensor sensing forces from the surrounding bilayer. The profound structural diversity in these channels suggests that the molecular mechanisms of force sensing follow unique structural blueprints. Here we determine the structures of plant and mammalian OSCA/TMEM63 proteins, allowing us to identify essential elements for mechanotransduction and propose roles for putative bound lipids in OSCA/TMEM63 mechanosensation. Briefly, the central cavity created by the dimer interface couples each subunit and modulates dimeric OSCA/TMEM63 channel mechanosensitivity through the modulating lipids while the cytosolic side of the pore is gated by a plug lipid that prevents the ion permeation. Our results suggest that the gating mechanism of OSCA/TMEM63 channels may combine structural aspects of the 'lipid-gated' mechanism of MscS and TRAAK channels and the calcium-induced gating mechanism of the TMEM16 family, which may provide insights into the structural rearrangements of TMEM16/TMC superfamilies. 10.1038/s41467-023-39688-8
Endoplasmic Reticulum-Plasma Membrane Junctions as Sites of Depolarization-Induced Ca Signaling in Excitable Cells. Annual review of physiology Membrane contact sites between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are found in all eukaryotic cells. In excitable cells they play unique roles in organizing diverse forms of Ca signaling as triggered by membrane depolarization. ER-PM junctions underlie crucial physiological processes such as excitation-contraction coupling, smooth muscle contraction and relaxation, and various forms of activity-dependent signaling and plasticity in neurons. In many cases the structure and molecular composition of ER-PM junctions in excitable cells comprise important regulatory feedback loops linking depolarization-induced Ca signaling at these sites to the regulation of membrane potential. Here, we describe recent findings on physiological roles and molecular composition of native ER-PM junctions in excitable cells. We focus on recent studies that provide new insights into canonical forms of depolarization-induced Ca signaling occurring at junctional triads and dyads of striated muscle, as well as the diversity of ER-PM junctions in these cells and in smooth muscle and neurons. 10.1146/annurev-physiol-032122-104610
Physiology of intracellular calcium buffering. Physiological reviews Calcium signaling underlies much of physiology. Almost all the Ca in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca buffers include small molecules and proteins, and experimentally Ca indicators will also buffer calcium. The chemistry of interactions between Ca and buffers determines the extent and speed of Ca binding. The physiological effects of Ca buffers are determined by the kinetics with which they bind Ca and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca, the Ca concentration, and whether Ca ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca signals as well as changes of Ca concentration in organelles. It can also facilitate Ca diffusion inside the cell. Ca buffering affects synaptic transmission, muscle contraction, Ca transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required. 10.1152/physrev.00042.2022
Advances in the cellular biology, biochemistry, and molecular biology of acidocalcisomes. Microbiology and molecular biology reviews : MMBR SUMMARYAcidocalcisomes are organelles conserved during evolution and closely related to the so-called volutin granules of bacteria and archaea, to the acidocalcisome-like vacuoles of yeasts, and to the lysosome-related organelles of animal species. All these organelles have in common their acidity and high content of polyphosphate and calcium. They are characterized by a variety of functions from storage of phosphorus and calcium to roles in Ca signaling, osmoregulation, blood coagulation, and inflammation. They interact with other organelles through membrane contact sites or by fusion, and have several enzymes, pumps, transporters, and channels. 10.1128/mmbr.00042-23
Endoplasmic Reticulum-Mitochondrial Contactology: Structure and Signaling Functions. Csordás György,Weaver David,Hajnóczky György Trends in cell biology Interorganellar contacts are increasingly recognized as central to the control of cellular behavior. These contacts, which typically involve a small fraction of the endomembrane surface, are local communication hubs that resemble synapses. We propose the term contactology to denote the analysis of interorganellar contacts. Endoplasmic reticulum (ER) contacts with mitochondria were recognized several decades ago; major roles in ion and lipid transfer, signaling, and membrane dynamics have been established, while others continue to emerge. The functional diversity of ER-mitochondrial (ER-mito) contacts is mirrored in their structural heterogeneity, with subspecialization likely supported by multiple, different linker-forming protein structures. The nanoscale size of the contacts has made studying their structure, function, and dynamics difficult. This review focuses on the structure of the ER-mito contacts, methods for studying them, and the roles of contacts in Ca and reactive oxygen species (ROS) signaling. 10.1016/j.tcb.2018.02.009
Discoveries in structure and physiology of mechanically activated ion channels. Kefauver J M,Ward A B,Patapoutian A Nature The ability to sense physical forces is conserved across all organisms. Cells convert mechanical stimuli into electrical or chemical signals via mechanically activated ion channels. In recent years, the identification of new families of mechanosensitive ion channels-such as PIEZO and OSCA/TMEM63 channels-along with surprising insights into well-studied mechanosensitive channels have driven further developments in the mechanotransduction field. Several well-characterized mechanosensory roles such as touch, blood-pressure sensing and hearing are now linked with primary mechanotransducers. Unanticipated roles of mechanical force sensing continue to be uncovered. Furthermore, high-resolution structures representative of nearly every family of mechanically activated channel described so far have underscored their diversity while advancing our understanding of the biophysical mechanisms of pressure sensing. Here we summarize recent discoveries in the physiology and structures of known mechanically activated ion channel families and discuss their implications for understanding the mechanisms of mechanical force sensing. 10.1038/s41586-020-2933-1
Molecular Interactions Between Plants and Insect Herbivores. Erb Matthias,Reymond Philippe Annual review of plant biology Diverse molecular processes regulate the interactions between plants and insect herbivores. Here, we review genes and proteins that are involved in plant-herbivore interactions and discuss how their discovery has structured the current standard model of plant-herbivore interactions. Plants perceive damage-associated and, possibly, herbivore-associated molecular patterns via receptors that activate early signaling components such as Ca, reactive oxygen species, and MAP kinases. Specific defense reprogramming proceeds via signaling networks that include phytohormones, secondary metabolites, and transcription factors. Local and systemic regulation of toxins, defense proteins, physical barriers, and tolerance traits protect plants against herbivores. Herbivores counteract plant defenses through biochemical defense deactivation, effector-mediated suppression of defense signaling, and chemically controlled behavioral changes. The molecular basis of plant-herbivore interactions is now well established for model systems. Expanding molecular approaches to unexplored dimensions of plant-insect interactions should be a future priority. 10.1146/annurev-arplant-050718-095910
A tale of many families: calcium channels in plant immunity. The Plant cell Plants launch a concerted immune response to dampen potential infections upon sensing microbial pathogen and insect invasions. The transient and rapid elevation of the cytosolic calcium concentration [Ca2+]cyt is among the essential early cellular responses in plant immunity. The free Ca2+ concentration in the apoplast is far higher than that in the resting cytoplasm. Thus, the precise regulation of calcium channel activities upon infection is the key for an immediate and dynamic Ca2+ influx to trigger downstream signaling. Specific Ca2+ signatures in different branches of the plant immune system vary in timing, amplitude, duration, kinetics, and sources of Ca2+. Recent breakthroughs in the studies of diverse groups of classical calcium channels highlight the instrumental role of Ca2+ homeostasis in plant immunity and cell survival. Additionally, the identification of some immune receptors as noncanonical Ca2+-permeable channels opens a new view of how immune receptors initiate cell death and signaling. This review aims to provide an overview of different Ca2+-conducting channels in plant immunity and highlight their molecular and genetic mode-of-actions in facilitating immune signaling. We also discuss the regulatory mechanisms that control the stability and activity of these channels. 10.1093/plcell/koac033
Merging Signaling with Structure: Functions and Mechanisms of Plant Glutamate Receptor Ion Channels. Annual review of plant biology Plant glutamate receptor-like (GLR) genes encode ion channels with demonstrated roles in electrical and calcium (Ca) signaling. The expansion of the GLR family along the lineage of land plants, culminating in the appearance of a multiclade system among flowering plants, has been a topic of interest since their discovery nearly 25 years ago. GLRs are involved in many physiological processes, from wound signaling to transcriptional regulation to sexual reproduction. Emerging evidence supports the notion that their fundamental functions are conserved among different groups of plants as well. In this review, we update the physiological and genetic evidence for GLRs, establishing their role in signaling and cell-cell communication. Special emphasis is given to the recent discussion of GLRs' atomic structures. Along with functional assays, a structural view of GLRs' molecular organization presents a window for novel hypotheses regarding the molecular mechanisms underpinning signaling associated with the ionic fluxes that GLRs regulate. Newly uncovered transcriptional regulations associated with GLRs-which propose the involvement of genes from all clades of in ways not previously observed-are discussed in the context of the broader impacts of GLR activity. We posit that the functions of GLRs in plant biology are probably much broader than anticipated, but describing their widespread involvement will only be possible with () a comprehensive understanding of the channel's properties at the molecular and structural levels, including protein-protein interactions, and () the design of new genetic approaches to explore stress and pathogen responses where precise transcriptional control may result in more precise testable hypotheses to overcome their apparent functional redundancies. 10.1146/annurev-arplant-070522-033255