TORC1 is required for the entry of yeast gametes into the mitotic cell cycle
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE110326 | GEO | 2019/12/31
REPOSITORIES: GEO
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Project description:The Target Of Rapamycin (TOR) protein is a Ser/Thr kinase that functions in two distinct multiprotein complexes: TORC1 and TORC2. These conserved complexes regulate many different aspects of cell growth in response to intra- and extracellular cues. Here we report the first bona fide substrate of yeast TORC1: the AGC-kinase Sch9. Six amino acids in the c-terminus of Sch9 are directly phosphorylated by TORC1. Phosphorylation of these residues is lost upon rapamycin-treatment as well as carbon- or nitrogen-starvation and transiently reduced following application of osmotic, oxidative or thermal stress. TORC1-dependent phosphorylation is required for Sch9 activity and replacement of residues phosphorylated by TORC1 with Asp/Glu renders Sch9 activity TORC1-independent. Sch9 is required for TORC1 to properly regulate ribosome biogenesis, translation initiation and entry into G0 phase, but not expression of Gln3-dependent genes. Our results suggest that Sch9 functions analogously to the mammalian TORC1 substrate S6K1 rather than the mTORC2 substrate PKB/Akt. Keywords: time course, cell type. Global transcriptional analysis of rapamycin response was conducted on cells expressing either a wild-type, Sch9(WT), or TOR-independent allele of Sch9, Sch9(2D3E). Reference samples used were cells collected immediately prior to rapamycin treatment for the respective cell genotypes. Test samples were collected 20, 30, 60, 90, 120, and 180min post rapamycin treatment.
2010-09-15 | E-GEOD-7660 | biostudies-arrayexpress
Project description:The Target Of Rapamycin (TOR) protein is a Ser/Thr kinase that functions in two distinct multiprotein complexes: TORC1 and TORC2. These conserved complexes regulate many different aspects of cell growth in response to intra- and extracellular cues. Here we report the first bona fide substrate of yeast TORC1: the AGC-kinase Sch9. Six amino acids in the c-terminus of Sch9 are directly phosphorylated by TORC1. Phosphorylation of these residues is lost upon rapamycin-treatment as well as carbon- or nitrogen-starvation and transiently reduced following application of osmotic, oxidative or thermal stress. TORC1-dependent phosphorylation is required for Sch9 activity and replacement of residues phosphorylated by TORC1 with Asp/Glu renders Sch9 activity TORC1-independent. Sch9 is required for TORC1 to properly regulate ribosome biogenesis, translation initiation and entry into G0 phase, but not expression of Gln3-dependent genes. Our results suggest that Sch9 functions analogously to the mammalian TORC1 substrate S6K1 rather than the mTORC2 substrate PKB/Akt. Keywords: time course, cell type.
2007-04-28 | GSE7660 | GEO
Project description:Target of rapamycin complex 1 (TORC1) is implicated in growth control and aging from yeast to humans. Fission yeast is emerging as a popular model organism to study TOR signaling, although rapamycin has been thought to not affect cell growth in this organism. Here we analyzed the effects of rapamycin and caffeine, singly and combined, on multiple cellular processes in fission yeast. The two drugs led to diverse and specific phenotypes that depended on TORC1 signaling pathway inhibition, including prolonged chronological lifespan, inhibition of global translation, inhibition of cell growth and division, and reprogramming of global gene expression mimicking nitrogen starvation. Rapamycin and caffeine differentially affected these various TORC1-dependent processes. Combined drug treatment augmented most phenotypes and effectively blocked cell growth. Although rapamycin showed a much more subtle effect on global translation than did caffeine, rapamycin was more effective in prolonging chronological lifespan. Rapamycin prolonged the lifespan of non-growing cells only when applied during the growth phase but not when applied after cells had stopped proliferation. The doses of rapamycin and caffeine strongly correlated with growth inhibition and with lifespan extension. This comprehensive analysis will inform future studies into TORC1 function and cellular aging in fission yeast and beyond.
2013-05-05 | E-MTAB-1489 | biostudies-arrayexpress
Project description:To determine how TORC1 and PKA cooperate to regulate cell growth, we performed temporal analysis of gene expression in yeast switched from a non-fermentable substrate, to glucose, in the presence and absence of TORC1 and PKA inhibitors. Quantitative analysis of these data reveals that PKA drives the expression of key cell growth genes during transitions into, and out of, the rapid growth state in glucose, while TORC1 is important for the steady-state expression of the same genes.
2019-07-19 | GSE133591 | GEO
Project description:The Ccr4-Not complex is an effector of multiple signaling pathways controlling gene transcription and mRNA turnover. Herein, we provide evidence that Ccr4-Not also activates nutrient signaling through the essential target of rapamycin complex 1 (TORC1) pathway. Mechanistically, Ccr4-Not loss decreases TORC1 signaling due to reduced stability of the vacuole V-ATPase that is required to activate TORC1 when associated with the Gtr1 GTPase containing EGO complex. Expressing a constitutively active Gtr1 in Ccr4-Not deficient cells bypasses the requirement for the V-ATPase and restores TORC1 signaling. Transcriptome analysis reveals that Ccr4-Not loss activates TORC1 repressed retrograde signaling to remodel metabolism and enhance mitochondrial function. Blocking retrograde signaling in a Ccr4-Not mutant further reduces TORC1 signaling, thus suggesting the enhanced mitochondrial metabolism due to Ccr4-Not loss is a metabolic adaptive response required to sustain TORC1 activity. Therefore, Ccr4-Not is a critical activator of TORC1 signaling that regulates cellular metabolism.
2019-10-04 | GSE138363 | GEO
Project description:To study TORC1-Atg1 signaling comprehensively and to identify potential additional foci of crosstalk, we chose a mass spectrometry (MS)-based phosphoproteomics strategy combing global proteomics screens in vivo with targeted analyses using in vitro kinase reactions. We present the currently largest compendium of rapamycin-sensitive phosphorylation events in the yeast Saccharomyces cerevisiae, identify numerous unknown TORC1 and Atg1 downstream phosphorylation events, and characterize hitherto unknown, functionally relevant TORC1 target sites on defined Atg proteins.
2019-09-30 | PXD013271 | Pride
Project description:Target of rapamycin complex 1 (TORC1) promotes biogenesis and inhibits degradation of ribosomes in response to nutrient availability. To ensure a basal supply of ribosomes, cells preserve a small pool of dormant ribosomes under nutrient-limited conditions. The regulation of dormant ribosomes is poorly characterized. Here, we show that upon inhibition of TORC1 by rapamycin or nitrogen starvation, Stm1 (suppressor of target of Myb protein 1) forms non-translating, dormant 80S ribosomes. Furthermore, Stm1-bound 80S ribosomes are protected from proteasomal degradation. Upon re-feeding, TORC1 directly phosphorylates and inhibits Stm1, thereby reactivating translation. Finally, SERBP1 (SERPINE1 mRNA binding protein), a mammalian ortholog of Stm1, forms dormant 80S ribosomes upon mTORC1 inhibition in mammalian cells. Thus, TORC1 regulates ribosomal dormancy in an evolutionarily conserved manner via a ribosome preservation factor.
2023-01-19 | PXD037117 | Pride
Project description:To adapt mitochondrial function to the ever-changing intra- and extra-cellular environment, multiple mitochondrial stress response (MSR) pathways, including the mitochondrial unfolded protein response (UPRmt), have evolved. However, how the mitochondrial stress signal is sensed and relayed to UPRmt transcription factors, such as ATFS-1 in Caenorhabditis elegans, remains largely unknown. Here, we show that a panel of vacuolar H+-ATPase (v-ATPase) subunits and the target of rapamycin complex 1 (TORC1) activity are essential for the cytosolic relay of mitochondrial stress to ATFS-1, and for the induction of the UPRmt. Mechanistically, mitochondrial stress stimulates v-ATPase/Rheb-dependent TORC1 activation, subsequently promoting ATFS-1 translation. Increased translation of ATFS-1 upon mitochondrial stress furthermore relies on a set of ribosomal components, but is independent of GCN-2/PEK-1 signaling. Finally, the v-ATPase and ribosomal subunits are required for mitochondrial surveillance and mitochondrial stress-induced longevity. These results reveal a v-ATPase-TORC1-ATFS-1 signaling pathway that links mitochondrial stress to the UPRmt through intimate crosstalks between multiple organelles.
2022-09-23 | GSE179517 | GEO
Project description:Background: Bacterial spores can remain dormant for decades, yet harbor the exceptional capacity to rapidly resume metabolic activity and recommence life. Although germinants and their corresponding receptors have been known for more than 30 years, the molecular events underlying this remarkable cellular transition from dormancy to full metabolic activity are only partially defined. Results: Here, we examined whether protein phospho-modifications occur during germination, the first step of exiting dormancy, thereby facilitating spore revival. Utilizing Bacillus subtilis as a model organism, we performed phosphoproteomic analysis to define the Ser/Thr/Tyr phosphoproteome of a reviving spore. The phosphoproteome was found to chiefly comprise newly identified phosphorylation sites located within proteins involved in basic biological functions, such as transcription, translation, carbon metabolism and spore-specific determinants. Quantitative comparison of dormant and germinating spore phosphoproteomes revealed phosphorylation dynamics, indicating that phospho-modifications could modulate protein activity during this cellular transition. Furthermore, by mutating select phosphorylation sites located within proteins representative of key biological processes, we established a functional connection between phosphorylation and the progression of spore revival. Conclusions: In this study we provide for the first time a phosphoproteomic view of a germinating bacterial spore. We show that the spore phosphoproteome is dynamic and present evidence that phosphorylation events play an integral role in facilitating spore revival.
2015-08-27 | PXD002559 | Pride
Project description:The protein kinase complex Target of Rapamycin complex 1 (TORC1) is a critical mediator of nutrient sensing that has been widely studied in cultured cells and yeast, yet our understanding of the regulatory activities of TORC1 in the context of a whole, multi-cellular organism is still very limited. Using C. elegans, we analyzed the DAF-15/Raptor-dependent phosphoproteome by quantitative mass spectrometry and characterized direct kinase targets by in vitro kinase assays. Here we show new targets of TORC1 that indicate previously unknown regulation of transcription and autophagy. Our results further show that DAF-15/Raptor is differentially expressed during postembryonic development, suggesting a dynamic role for TORC1 signaling throughout development. This study provides a comprehensive view of the TORC1 phosphoproteome and reveals more than 100 DAF-15/Raptor-dependent phosphosites, reflecting the complex function of TORC1 in a whole, multi-cellular organism.
2022-04-22 | PXD032260 | Pride