Phosphoregulation of the yeast Pma1 H+-ATPase autoinhibitory domain involves the Ptk1/2 kinases and the Glc7 PP1 phosphatase and is under TORC1 control.
PLoS genetics
Plasma membrane (PM) H+-ATPases of the P-type family are highly conserved in yeast, other fungi, and plants. Their main role is to establish an H+ gradient driving active transport of small ions and metabolites across the PM and providing the main component of the PM potential. Furthermore, in both yeast and plant cells, conditions have been described under which active H+-ATPases promote activation of TORC1, the rapamycin-sensitive kinase complex controlling cell growth. Fungal and plant PM H+-ATPases are self-inhibited by their respective cytosolic carboxyterminal tails unless this domain is phosphorylated at specific residues. In the yeast H+-ATPase Pma1, neutralization of this autoinhibitory domain depends mostly on phosphorylation of the adjacent Ser911 and Thr912 residues, but the kinase(s) and phosphatase(s) controlling this tandem phosphorylation remain unknown. In this study, we show that S911-T912 phosphorylation in Pma1 is mediated by the largely redundant Ptk1 and Ptk2 kinase paralogs. Dephosphorylation of S911-T912, as occurs under glucose starvation, is dependent on the Glc7 PP1 phosphatase. Furthermore, proper S911-T912 phosphorylation in Pma1 is required for optimal TORC1 activation upon H+ influx coupled amino-acid uptake. We finally show that TORC1 controls S911-T912 phosphorylation in a manner suggesting that activated TORC1 promotes feedback inhibition of Pma1. Our results shed important new light on phosphoregulation of the yeast Pma1 H+-ATPase and on its interconnections with TORC1.
10.1371/journal.pgen.1011121
TORC1 signaling regulates cytoplasmic pH through Sir2 in yeast.
Devare Mayur Nimbadas,Kim Yeong Hyeock,Jung Joohye,Kang Woo Kyu,Kwon Ki-Sun,Kim Jeong-Yoon
Aging cell
Glucose controls the phosphorylation of silent information regulator 2 (Sir2), a NAD -dependent protein deacetylase, which regulates the expression of the ATP-dependent proton pump Pma1 and replicative lifespan (RLS) in yeast. TORC1 signaling, which is a central regulator of cell growth and lifespan, is regulated by glucose as well as nitrogen sources. In this study, we demonstrate that TORC1 signaling controls Sir2 phosphorylation through casein kinase 2 (CK2) to regulate PMA1 expression and cytoplasmic pH (pHc) in yeast. Inhibition of TORC1 signaling by either TOR1 deletion or rapamycin treatment decreased PMA1 expression, pHc, and vacuolar pH, whereas activation of TORC1 signaling by expressing constitutively active GTR1 (GTR1Q65L) resulted in the opposite phenotypes. Deletion of SIR2 or expression of a phospho-mutant form of SIR2 increased PMA1 expression, pHc, and vacuolar pH in the tor1Δ mutant, suggesting a functional interaction between Sir2 and TORC1 signaling. Furthermore, deletion of TOR1 or KNS1 encoding a LAMMER kinase decreased the phosphorylation level of Sir2, suggesting that TORC1 signaling controls Sir2 phosphorylation. It was also found that Sit4, a protein phosphatase 2A (PP2A)-like phosphatase, and Kns1 are required for TORC1 signaling to regulate PMA1 expression and that TORC1 signaling and the cyclic AMP (cAMP)/protein kinase A (PKA) pathway converge on CK2 to regulate PMA1 expression through Sir2. Taken together, these findings suggest that TORC1 signaling regulates PMA1 expression and pHc through the CK2-Sir2 axis, which is also controlled by cAMP/PKA signaling in yeast.
10.1111/acel.13151
Casein Kinase 1, a Negative Regulator of the Plasma Membrane H-ATPase Pma1, Is Required for Development and Pathogenicity.
Journal of fungi (Basel, Switzerland)
Like many hemibiotrophic plant pathogens, the root-infecting vascular wilt fungus induces an increase in the pH of the surrounding host tissue. How alkalinization promotes fungal infection is not fully understood, but recent studies point towards the role of cytosolic pH (pH) and mitogen-activated protein kinase (MAPK) signaling. In fungi, pH is mainly controlled by the essential plasma membrane H-ATPase Pma1. Here we created mutants of lacking casein kinase 1 (Ck1), a known negative regulator of Pma1. We found that the Δ mutants have constitutively high Pma1 activity and exhibit reduced alkalinization of the surrounding medium as well as decreased hyphal growth and conidiation. Importantly, the Δ mutants exhibit defects in hyphal chemotropism towards plant roots and in pathogenicity on tomato plants. Thus, Ck1 is a key regulator of the development and virulence of .
10.3390/jof8121300
The yeast H-ATPase Pma1 promotes Rag/Gtr-dependent TORC1 activation in response to H-coupled nutrient uptake.
Saliba Elie,Evangelinos Minoas,Gournas Christos,Corrillon Florent,Georis Isabelle,André Bruno
eLife
The yeast Target of Rapamycin Complex 1 (TORC1) plays a central role in controlling growth. How amino acids and other nutrients stimulate its activity via the Rag/Gtr GTPases remains poorly understood. We here report that the signal triggering Rag/Gtr-dependent TORC1 activation upon amino-acid uptake is the coupled H influx catalyzed by amino-acid/H symporters. H-dependent uptake of other nutrients, ionophore-mediated H diffusion, and inhibition of the vacuolar V-ATPase also activate TORC1. As the increase in cytosolic H elicited by these processes stimulates the compensating H-export activity of the plasma membrane H-ATPase (Pma1), we have examined whether this major ATP-consuming enzyme might be involved in TORC1 control. We find that when the endogenous Pma1 is replaced with a plant H-ATPase, H influx or increase fails to activate TORC1. Our results show that H influx coupled to nutrient uptake stimulates TORC1 activity and that Pma1 is a key actor in this mechanism.
10.7554/eLife.31981
Inositol phosphosphingolipid phospholipase C1 regulates plasma membrane ATPase (Pma1) stability in Cryptococcus neoformans.
FEBS letters
Cryptococcus neoformans is a facultative intracellular pathogen, which can replicate in the acidic environment inside phagolysosomes. Deletion of the enzyme inositol-phosphosphingolipid-phospholipase-C (Isc1) makes C. neoformans hypersensitive to acidic pH likely by inhibiting the function of the proton pump, plasma membrane ATPase (Pma1). In this work, we examined the role of Isc1 on Pma1 transport and oligomerization. Our studies showed that Isc1 deletion did not affect Pma1 synthesis or transport, but significantly inhibited Pma1 oligomerization. Interestingly, Pma1 oligomerization could be restored by supplementing the medium with phytoceramide. These results offer insight into the mechanism of intracellular survival of C. neoformans.
10.1016/j.febslet.2014.09.005
Overexpression of PMA1 enhances tolerance to various types of stress and constitutively activates the SAPK pathways in Saccharomyces cerevisiae.
Lee Yeji,Nasution Olviyani,Lee Young Mi,Kim Eunjung,Choi Wonja,Kim Wankee
Applied microbiology and biotechnology
PMA1 encodes a transmembrane polypeptide that functions to pump protons out of the cell. Ectopic PMA1 overexpression in Saccharomyces cerevisiae enhances tolerance to weak acids, reactive oxygen species (ROS) and ethanol, and changes the following physiological properties: better proton efflux, lower membrane permeability, and lessened internal hydrogen peroxide production. The enhanced stress tolerance was dependent on the mitogen-activated protein kinase (MAPK) Hog1 of the high osmolarity glycerol (HOG) pathway, but not the MAPK Slt2 of the cell wall integrity (CWI) pathway; however, a PMA1 overexpression constitutively activated both Hog1 and Slt2. The constitutive Hog1 activation required the MAPK kinase kinase (MAP3K) Ssk2 of the HOG pathway, but not Ste11 and Ssk22, two other MAP3Ks of the same pathway. The constitutive Slt2 activation did not require Rom2 and the membrane sensors of the CWI pathway, whereas Bck1 was indispensable. The PMA1 overexpression activated the stress response element but not the cyclic AMP response element and the Rlm1 transcription factor. PMA1 overexpression may facilitate the construction of industrial strains with simultaneous tolerance to weak acids, ROS, and ethanol.
10.1007/s00253-016-7898-5
Structure and activation mechanism of the hexameric plasma membrane H-ATPase.
Nature communications
The S. cerevisiae plasma membrane H-ATPase, Pma1, is a P3A-type ATPase and the primary protein component of the membrane compartment of Pma1 (MCP). Like other plasma membrane H-ATPases, Pma1 assembles and functions as a hexamer, a property unique to this subfamily among the larger family of P-type ATPases. It has been unclear how Pma1 organizes the yeast membrane into MCP microdomains, or why it is that Pma1 needs to assemble into a hexamer to establish the membrane electrochemical proton gradient. Here we report a high-resolution cryo-EM study of native Pma1 hexamers embedded in endogenous lipids. Remarkably, we found that the Pma1 hexamer encircles a liquid-crystalline membrane domain composed of 57 ordered lipid molecules. The Pma1-encircled lipid patch structure likely serves as the building block of the MCP. At pH 7.4, the carboxyl-terminal regulatory α-helix binds to the phosphorylation domains of two neighboring Pma1 subunits, locking the hexamer in the autoinhibited state. The regulatory helix becomes disordered at lower pH, leading to activation of the Pma1 hexamer. The activation process is accompanied by a 6.7 Å downward shift and a 40° rotation of transmembrane helices 1 and 2 that line the proton translocation path. The conformational changes have enabled us to propose a detailed mechanism for ATP-hydrolysis-driven proton pumping across the plasma membrane. Our structures will facilitate the development of antifungal drugs that target this essential protein.
10.1038/s41467-021-26782-y
Fungal Plasma Membrane H-ATPase: Structure, Mechanism, and Drug Discovery.
Journal of fungi (Basel, Switzerland)
The fungal plasma membrane H-ATPase (Pma1) pumps protons out of the cell to maintain the transmembrane electrochemical gradient and membrane potential. As an essential P-type ATPase uniquely found in fungi and plants, Pma1 is an attractive antifungal drug target. Two recent Cryo-EM studies on Pma1 have revealed its hexameric architecture, autoinhibitory and activation mechanisms, and proton transport mechanism. These structures provide new perspectives for the development of antifungal drugs targeting Pma1. In this article, we review the history of Pma1 structure determination, the latest structural insights into Pma1, and drug discoveries targeting Pma1.
10.3390/jof10040273
Sphingoid base synthesis is required for oligomerization and cell surface stability of the yeast plasma membrane ATPase, Pma1.
Wang Qiongqing,Chang Amy
Proceedings of the National Academy of Sciences of the United States of America
The plasma membrane H(+)-ATPase, Pma1, is an essential and long-lived integral membrane protein. Previous work has demonstrated that the Pma1-D378N mutant is a substrate for endoplasmic reticulum (ER)-associated degradation and causes a dominant negative effect on cell growth by preventing ER export of wild-type Pma1. We now show that Pma1-D378N is ubiquitylated, and it heterooligomerizes with wild-type Pma1, resulting in ubiquitylation and ER-associated degradation of wild-type Pma1. In temperature-sensitive lcb1-100 cells, defective in sphingoid base synthesis, Pma1 fails to oligomerize. At 30 degrees C, lcb1-100 is a suppressor of pma1-D378N because wild-type Pma1 fails to heterooligomerize with Pma1-D378N; wild-type Pma1 moves to the cell surface, indicating that oligomerization is not required for delivery to the plasma membrane. Even in the absence of Pma1-D378N, wild-type Pma1 is ubiquitylated and it undergoes internalization from the cell surface and vacuolar degradation at 30 degrees C in lcb1-100 cells. At 37 degrees C in lcb1-100 cells, a more severe defect occurs in sphingoid base synthesis, and targeting of newly synthesized Pma1 to the plasma membrane is impaired. These data indicate requirements for sphingolipids at three discrete stages: Pma1 oligomerization at the ER, targeting to the plasma membrane, and stability at the cell surface.
10.1073/pnas.202115499