The Stress-Sensing TORC2 Complex Activates Yeast AGC-Family Protein Kinase Ypk1 at Multiple Novel Sites

Leskoske, Kristin L.; Roelants, Françoise M.; Marshall, Maria Nieves Martinez; Hill, Jennifer; Thorner, Jeremy

doi:10.1534/genetics.117.1124

Cited by 33 publications

(58 citation statements)

References 83 publications

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“…Strikingly, however, even though Avo2 is nonessential for cell viability under nonstress conditions, we found that Avo2 is essential for cell survival during myriocin-induced sphingolipid depletion (Fig. 2B, top row), a condition in which cells require full TORC2-mediated activation of Ypk1 to survive (Roelants et al 2011;Leskoske et al 2017). Furthermore, compared with cells expressing wild-type Avo2 or Avo2 9A , cells expressing Avo2 9E were much more sensitive to the growth inhibitory effect of myriocin ( Fig.…”

Section: Mapk Phosphorylation Of Avo2 Impairs Torc2 Activitymentioning

confidence: 84%

“…Sln1 is a histidine kinase similar to those in bacterial two-component signaling systems, and its inactivation, as occurs during hyperosmotic shock, leads to activation of the Hog1 MAPK (Saito and Posas 2012). In a global screen of the Saccharomyces cerevisiae kinome, we found that, like a tor2 ts mutant (Leskoske et al 2017), when a sln1 ts mutant was shifted to the restrictive temperature, there was a dramatic loss of TORC2-dependent Ypk1 phosphorylation (Supplemental Fig. S2A) that was accompanied by hyperphosphorylation of Avo2 (Supplemental Fig.…”

Section: Torc2 Is Down-regulated During Sustained Sln1 Inactivationmentioning

confidence: 94%

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Phosphorylation by the stress-activated MAPK Slt2 down-regulates the yeast TOR complex 2

Leskoske

Roelants

Emmerstorfer-Augustin

et al. 2018

Genes Dev.

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Saccharomyces cerevisiae target of rapamycin (TOR) complex 2 (TORC2) is an essential regulator of plasma membrane lipid and protein homeostasis. How TORC2 activity is modulated in response to changes in the status of the cell envelope is unclear. Here we document that TORC2 subunit Avo2 is a direct target of Slt2, the mitogenactivated protein kinase (MAPK) of the cell wall integrity pathway. Activation of Slt2 by overexpression of a constitutively active allele of an upstream Slt2 activator (Pkc1) or by auxin-induced degradation of a negative Slt2 regulator (Sln1) caused hyperphosphorylation of Avo2 at its MAPK phosphoacceptor sites in a Slt2-dependent manner and diminished TORC2-mediated phosphorylation of its major downstream effector, protein kinase Ypk1. Deletion of Avo2 or expression of a phosphomimetic Avo2 allele rendered cells sensitive to two stresses (myriocin treatment and elevated exogenous acetic acid) that the cell requires Ypk1 activation by TORC2 to survive. Thus, Avo2 is necessary for optimal TORC2 activity, and Slt2-mediated phosphorylation of Avo2 down-regulates TORC2 signaling. Compared with wild-type Avo2, phosphomimetic Avo2 shows significant displacement from the plasma membrane, suggesting that Slt2 inhibits TORC2 by promoting Avo2 dissociation. Our findings are the first demonstration that TORC2 function is regulated by MAPK-mediated phosphorylation.

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Section: Mapk Phosphorylation Of Avo2 Impairs Torc2 Activitymentioning

confidence: 84%

Section: Torc2 Is Down-regulated During Sustained Sln1 Inactivationmentioning

confidence: 94%

Phosphorylation by the stress-activated MAPK Slt2 down-regulates the yeast TOR complex 2

Leskoske

Roelants

Emmerstorfer-Augustin

et al. 2018

Genes Dev.

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“…TORC2 phosphorylates Ypk1 at multiple sites at its C-terminal end, thereby stimulating its activity [ 22 , 24 , 39 ]. Ypk1 is a member of the sub-family of eukaryotic protein kinases first defined by the related protein kinases cyclic-3’5’-AMP-dependent protein kinase (PKA), cyclic-3’5’-GMP-dependent protein kinase (PKG), and the conventional Ca 2+ -, DAG-, and PtdSer-activated protein kinases (PKC) (AGC-family of protein kinases) [ 40 , 41 ].…”

Section: Torc2 Effectorsmentioning

confidence: 99%

The TORC2‐Dependent Signaling Network in the Yeast Saccharomyces cerevisiae

et al. 2017

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To grow, eukaryotic cells must expand by inserting glycerolipids, sphingolipids, sterols, and proteins into their plasma membrane, and maintain the proper levels and bilayer distribution. A fungal cell must coordinate growth with enlargement of its cell wall. In Saccharomyces cerevisiae, a plasma membrane-localized protein kinase complex, Target of Rapamicin (TOR) complex-2 (TORC2) (mammalian ortholog is mTORC2), serves as a sensor and master regulator of these plasma membrane- and cell wall-associated events by directly phosphorylating and thereby stimulating the activity of two types of effector protein kinases: Ypk1 (mammalian ortholog is SGK1), along with a paralog (Ypk2); and, Pkc1 (mammalian ortholog is PKN2/PRK2). Ypk1 is a central regulator of pathways and processes required for plasma membrane lipid and protein homeostasis, and requires phosphorylation on its T-loop by eisosome-associated protein kinase Pkh1 (mammalian ortholog is PDK1) and a paralog (Pkh2). For cell survival under various stresses, Ypk1 function requires TORC2-mediated phosphorylation at multiple sites near its C terminus. Pkc1 controls diverse processes, especially cell wall synthesis and integrity. Pkc1 is also regulated by Pkh1- and TORC2-dependent phosphorylation, but, in addition, by interaction with Rho1-GTP and lipids phosphatidylserine (PtdSer) and diacylglycerol (DAG). We also describe here what is currently known about the downstream substrates modulated by Ypk1-mediated and Pkc1-mediated phosphorylation.

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“…TORC1 is required for the expression of Pma1 protein and the full activity of the proton pump to resist pH stress (5). TORC2 phosphorylates and stimulates the downstream protein kinase Ypk1/ Ypk2 to regulate membrane lipids and proteins (26,27). In addition, the Snf1 pathway is involved in regulation of cell membrane biosynthesis, given that deletion of the subunits of the SNF1 complex resulted in hypersensitivity to cell membrane stress (28,29).…”

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confidence: 99%

Cg Hog1-Mediated Cg Rds2 Phosphorylation Alters Glycerophospholipid Composition To Coordinate Osmotic Stress in Candida glabrata

Zhang

Zhu

et al. 2019

Appl Environ Microbiol

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Under stress conditions, Hog1 is required for cell survival through transiently phosphorylating downstream targets and reprogramming gene expression. Here, we report that Candida glabrata Hog1 (CgHog1) interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, in response to osmotic stress. Additionally, we found that deletion of CgRDS2 led to decreases in cell growth and cell survival by 23.4% and 39.6%, respectively, at 1.5 M NaCl, compared with levels of the wild-type strain. This is attributed to significant downregulation of the expression levels of glycerophospholipid metabolism genes. As a result, the content of total glycerophospholipid decreased by 30.3%. Membrane integrity also decreased 47.6% in the Cgrds2Δ strain at 1.5 M NaCl. In contrast, overexpression of CgRDS2 increased the cell growth and cell survival by 10.2% and 6.3%, respectively, owing to a significant increase in the total glycerophospholipid content and increased membrane integrity by 27.2% and 12.1%, respectively, at 1.5 M NaCl, compared with levels for the wild-type strain. However, a strain in which the CgRDS2 gene encodes the replacement of Ser64 and Thr97 residues with alanines (Cgrds22A), harboring a CgRds2 protein that was not phosphorylated by CgHog1, failed to promote glycerophospholipid metabolism and membrane integrity at 1.5 M NaCl. Thus, the above results demonstrate that CgHog1-mediated CgRds2 phosphorylation enhanced glycerophospholipid composition and membrane integrity to resist osmotic stress in C. glabrata. IMPORTANCE This study explored the role of CgHog1-mediated CgRds2 phosphorylation in response to osmotic stress in Candida glabrata. CgHog1 interacts with and phosphorylates CgRds2, a zinc cluster transcription factor, under osmotic stress. Phosphorylated CgRds2 plays an important role in increasing glycerophospholipid composition and membrane integrity, thereby enhancing cell growth and survival.

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The Stress-Sensing TORC2 Complex Activates Yeast AGC-Family Protein Kinase Ypk1 at Multiple Novel Sites

Cited by 33 publications

References 83 publications

Phosphorylation by the stress-activated MAPK Slt2 down-regulates the yeast TOR complex 2

Phosphorylation by the stress-activated MAPK Slt2 down-regulates the yeast TOR complex 2

The TORC2‐Dependent Signaling Network in the Yeast Saccharomyces cerevisiae

Cg Hog1-Mediated Cg Rds2 Phosphorylation Alters Glycerophospholipid Composition To Coordinate Osmotic Stress in Candida glabrata

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