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Bowman RW, Jordahl EM, Davis S, Hedayati S, Barsouk H, Ozbaki-Yagan N, Chiang A, Li Y, O’Donnell AF. TORC1 Signaling Controls the Stability and Function of α-Arrestins Aly1 and Aly2. Biomolecules 2022; 12:biom12040533. [PMID: 35454122 PMCID: PMC9031309 DOI: 10.3390/biom12040533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 02/06/2023] Open
Abstract
Nutrient supply dictates cell signaling changes, which in turn regulate membrane protein trafficking. To better exploit nutrients, cells relocalize membrane transporters via selective protein trafficking. Key in this reshuffling are the α-arrestins, selective protein trafficking adaptors conserved from yeast to man. α-Arrestins bind membrane proteins, controlling the ubiquitination and endocytosis of many transporters. To prevent the spurious removal of membrane proteins, α-arrestin-mediated endocytosis is kept in check through phospho-inhibition. This phospho-regulation is complex, with up to 87 phospho-sites on a single α-arrestin and many kinases/phosphatases targeting α-arrestins. To better define the signaling pathways controlling paralogous α-arrestins, Aly1 and Aly2, we screened the kinase and phosphatase deletion (KinDel) library, which is an array of all non-essential kinase and phosphatase yeast deletion strains, for modifiers of Aly-mediated phenotypes. We identified many Aly regulators, but focused our studies on the TORC1 kinase, a master regulator of nutrient signaling across eukaryotes. We found that TORC1 and its signaling effectors, the Sit4 protein phosphatase and Npr1 kinase, regulate the phosphorylation and stability of Alys. When Sit4 is lost, Alys are hyperphosphorylated and destabilized in an Npr1-dependent manner. These findings add new dimensions to our understanding of TORC1 regulation of α-arrestins and have important ramifications for cellular metabolism.
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Affiliation(s)
- Ray W. Bowman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Eric M. Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Sydnie Davis
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Stefanie Hedayati
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Hannah Barsouk
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Nejla Ozbaki-Yagan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Annette Chiang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
| | - Yang Li
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Allyson F. O’Donnell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA; (R.W.B.II); (E.M.J.); (S.D.); (S.H.); (H.B.); (N.O.-Y.); (A.C.)
- Correspondence: ; Tel.: +1-412-648-4270
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Wang TH, Tseng WC, Leu YL, Chen CY, Lee WC, Chi YC, Cheng SF, Lai CY, Kuo CH, Yang SL, Yang SH, Shen JJ, Feng CH, Wu CC, Hwang TL, Wang CJ, Wang SH, Chen CC. The flavonoid corylin exhibits lifespan extension properties in mouse. Nat Commun 2022; 13:1238. [PMID: 35264584 PMCID: PMC8907184 DOI: 10.1038/s41467-022-28908-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/16/2022] [Indexed: 01/23/2023] Open
Abstract
In the long history of traditional Chinese medicine, single herbs and complex formulas have been suggested to increase lifespan. However, the identification of single molecules responsible for lifespan extension has been challenging. Here, we collected a list of traditional Chinese medicines with potential longevity properties from pharmacopeias. By utilizing the mother enrichment program, we systematically screened these traditional Chinese medicines and identified a single herb, Psoralea corylifolia, that increases lifespan in Saccharomyces cerevisiae. Next, twenty-two pure compounds were isolated from Psoralea corylifolia. One of the compounds, corylin, was found to extend the replicative lifespan in yeast by targeting the Gtr1 protein. In human umbilical vein endothelial cells, RNA sequencing data showed that corylin ameliorates cellular senescence. We also examined an in vivo mammalian model, and found that corylin extends lifespan in mice fed a high-fat diet. Taken together, these findings suggest that corylin may promote longevity.
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Affiliation(s)
- Tong-Hong Wang
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Wei-Che Tseng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Yann-Lii Leu
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Yuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Wen-Chih Lee
- Office of Research and Development, Tzu Chi University, Hualien, Taiwan
| | - Ying-Chih Chi
- Cryo-EM Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, USA
| | - Shu-Fang Cheng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Yu Lai
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chen-Hsin Kuo
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Shu-Ling Yang
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Sien-Hung Yang
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan.,Division of Chinese Internal Medicine, Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jiann-Jong Shen
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Hao Feng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Ching Wu
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan.,Department of Otolaryngology-Head & Neck Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.,Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsong-Long Hwang
- Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.,Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chia-Jen Wang
- Cell Therapy Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shu-Huei Wang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Chin-Chuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan. .,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.
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53
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Tate JJ, Marsikova J, Vachova L, Palkova Z, Cooper TG. Effects of abolishing Whi2 on the proteome and nitrogen catabolite repression-sensitive protein production. G3 (BETHESDA, MD.) 2022; 12:jkab432. [PMID: 35100365 PMCID: PMC9210300 DOI: 10.1093/g3journal/jkab432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 12/08/2021] [Indexed: 11/17/2022]
Abstract
In yeast physiology, a commonly used reference condition for many experiments, including those involving nitrogen catabolite repression (NCR), is growth in synthetic complete (SC) medium. Four SC formulations, SCCSH,1990, SCCSH,1994, SCCSH,2005, and SCME, have been used interchangeably as the nitrogen-rich medium of choice [Cold Spring Harbor Yeast Course Manuals (SCCSH) and a formulation in the methods in enzymology (SCME)]. It has been tacitly presumed that all of these formulations support equivalent responses. However, a recent report concluded that (i) TorC1 activity is downregulated by the lower concentration of primarily leucine in SCME relative to SCCSH. (ii) The Whi2-Psr1/2 complex is responsible for this downregulation. TorC1 is a primary nitrogen-responsive regulator in yeast. Among its downstream targets is control of NCR-sensitive transcription activators Gln3 and Gat1. They in turn control production of catabolic transporters and enzymes needed to scavenge poor nitrogen sources (e.g., Proline) and activate autophagy (ATG14). One of the reporters used in Chen et al. was an NCR-sensitive DAL80-GFP promoter fusion. This intrigued us because we expected minimal if any DAL80 expression in SC medium. Therefore, we investigated the source of the Dal80-GFP production and the proteomes of wild-type and whi2Δ cells cultured in SCCSH and SCME. We found a massive and equivalent reorientation of amino acid biosynthetic proteins in both wild-type and whi2Δ cells even though both media contained high overall concentrations of amino acids. Gcn2 appears to play a significant regulatory role in this reorientation. NCR-sensitive DAL80 expression and overall NCR-sensitive protein production were only marginally affected by the whi2Δ. In contrast, the levels of 58 proteins changed by an absolute value of log2 between 3 and 8 when Whi2 was abolished relative to wild type. Surprisingly, with only two exceptions could those proteins be related in GO analyses, i.e., GO terms associated with carbohydrate metabolism and oxidative stress after shifting a whi2Δ from SCCSH to SCME for 6 h. What was conspicuously missing were proteins related by TorC1- and NCR-associated GO terms.
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Affiliation(s)
- Jennifer J Tate
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jana Marsikova
- Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, 128 00 Prague, Czech Republic
| | - Libuse Vachova
- Institute of Microbiology of the Czech Academy of Sciences, BIOCEV, 142 20 Prague, Czech Republic
| | - Zdena Palkova
- Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, 128 00 Prague, Czech Republic
| | - Terrance G Cooper
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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54
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Lei Y, Huang Y, Wen X, Yin Z, Zhang Z, Klionsky DJ. How Cells Deal with the Fluctuating Environment: Autophagy Regulation under Stress in Yeast and Mammalian Systems. Antioxidants (Basel) 2022; 11:antiox11020304. [PMID: 35204187 PMCID: PMC8868404 DOI: 10.3390/antiox11020304] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 01/28/2022] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Eukaryotic cells frequently experience fluctuations of the external and internal environments, such as changes in nutrient, energy and oxygen sources, and protein folding status, which, after reaching a particular threshold, become a type of stress. Cells develop several ways to deal with these various types of stress to maintain homeostasis and survival. Among the cellular survival mechanisms, autophagy is one of the most critical ways to mediate metabolic adaptation and clearance of damaged organelles. Autophagy is maintained at a basal level under normal growing conditions and gets stimulated by stress through different but connected mechanisms. In this review, we summarize the advances in understanding the autophagy regulation mechanisms under multiple types of stress including nutrient, energy, oxidative, and ER stress in both yeast and mammalian systems.
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Affiliation(s)
- Yuchen Lei
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuxiang Huang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xin Wen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhangyuan Yin
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhihai Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Daniel J. Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; (Y.L.); (Y.H.); (X.W.); (Z.Y.); (Z.Z.)
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence:
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Abstract
The target of rapamycin (TOR) kinase is a master regulator that integrates nutrient signals to promote cell growth in all eukaryotes. It is well established that amino acids and glucose are major regulators of TOR signaling in yeast and metazoan, but whether and how TOR responds to carbon availability in photosynthetic organisms is less understood. In this study, we showed that photosynthetic assimilation of CO2 by the Calvin-Benson-Bassham (CBB) cycle regulates TOR activity in the model single-celled microalga Chlamydomonas reinhardtii Stimulation of CO2 fixation boosted TOR activity, whereas inhibition of the CBB cycle and photosynthesis down-regulated TOR. We uncovered a tight link between TOR activity and the endogenous level of a set of amino acids including Ala, Glu, Gln, Leu, and Val through the modulation of CO2 fixation and the use of amino acid synthesis inhibitors. Moreover, the finding that the Chlamydomonas starch-deficient mutant sta6 displayed disproportionate TOR activity and high levels of most amino acids, particularly Gln, further connected carbon assimilation and amino acids to TOR signaling. Thus, our results showed that CO2 fixation regulates TOR signaling, likely through the synthesis of key amino acids.
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56
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Kumar S, Mashkoor M, Grove A. Yeast Crf1p: An activator in need is an activator indeed. Comput Struct Biotechnol J 2022; 20:107-116. [PMID: 34976315 PMCID: PMC8688861 DOI: 10.1016/j.csbj.2021.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/15/2021] [Accepted: 12/03/2021] [Indexed: 11/10/2022] Open
Abstract
Ribosome biogenesis is an energetically costly process, and tight regulation is required for stoichiometric balance between components. This requires coordination of RNA polymerases I, II, and III. Lack of nutrients or the presence of stress leads to downregulation of ribosome biogenesis, a process for which mechanistic target of rapamycin complex I (mTORC1) is key. mTORC1 activity is communicated by means of specific transcription factors, and in yeast, which is a primary model system in which transcriptional coordination has been delineated, transcription factors involved in regulation of ribosomal protein genes include Fhl1p and its cofactors, Ifh1p and Crf1p. Ifh1p is an activator, whereas Crf1p has been implicated in maintaining the repressed state upon mTORC1 inhibition. Computational analyses of evolutionary relationships have indicated that Ifh1p and Crf1p descend from a common ancestor. Here, we discuss recent evidence, which suggests that Crf1p also functions as an activator. We propose a model that consolidates available experimental evidence, which posits that Crf1p functions as an alternate activator to prevent the stronger activator Ifh1p from re-binding gene promoters upon mTORC1 inhibition. The correlation between retention of Crf1p in related yeast strains and duplication of ribosomal protein genes suggests that this backup activation may be important to ensure gene expression when Ifh1p is limiting. With ribosome biogenesis as a hallmark of cell growth, failure to control assembly of ribosomal components leads to several human pathologies. A comprehensive understanding of mechanisms underlying this process is therefore of the essence.
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Key Words
- CK2, casein kinase 2
- Crf1, corepressor with forkhead like
- Crf1p
- FHA, forkhead-associated
- FHB, forkhead-binding
- FKBP, FK506 binding protein
- Fhl1, forkhead like
- Fpr1, FK506-sensitive proline rotamase
- Gene regulation
- Hmo1, high mobility group
- Ifh1, interacts with forkhead like
- Ifh1p
- RASTR, ribosome assembly stress response
- RP, ribosomal protein
- Rap1, repressor/activator protein
- RiBi, ribosome biogenesis
- Ribosomal protein
- Ribosome biogenesis
- Sfp1, split finger protein
- WGD, whole genome duplication
- mTORC1
- mTORC1, mechanistic target of rapamycin complex 1
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Affiliation(s)
- Sanjay Kumar
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Muneera Mashkoor
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Anne Grove
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Albehaijani SHI, Macreadie I, Morrissey CO, Boyce KJ. OUP accepted manuscript. JAC Antimicrob Resist 2022; 4:dlac033. [PMID: 35402912 PMCID: PMC8986524 DOI: 10.1093/jacamr/dlac033] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/08/2022] [Indexed: 12/02/2022] Open
Abstract
Background Fungal infections are common life-threatening diseases amongst immunodeficient individuals. Invasive fungal disease is commonly treated with an azole antifungal agent, resulting in selection pressure and the emergence of drug resistance. Antifungal resistance is associated with higher mortality rates and treatment failure, making the current clinical management of fungal disease very challenging. Clinical isolates from a variety of fungi have been shown to contain mutations in the MSH2 gene, encoding a component of the DNA mismatch repair pathway. Mutation of MSH2 results in an elevated mutation rate that can increase the opportunity for selectively advantageous mutations to occur, accelerating the development of antifungal resistance. Objectives To characterize the molecular mechanisms causing the microevolutionary emergence of antifungal resistance in msh2 mismatch repair mutants of Cryptococcus neoformans. Methods The mechanisms resulting in the emergence of antifungal resistance were investigated using WGS, characterization of deletion mutants and measuring ploidy changes. Results The genomes of resistant strains did not possess mutations in ERG11 or other genes of the ergosterol biosynthesis pathway. Antifungal resistance was due to small contributions from mutations in many genes. MSH2 does not directly affect ploidy changes. Conclusions This study provides evidence that resistance to fluconazole can evolve independently of ERG11 mutations. A common microevolutionary route to the emergence of antifungal resistance involves the accumulation of mutations that alter stress signalling, cellular efflux, membrane trafficking, epigenetic modification and aneuploidy. This complex pattern of microevolution highlights the significant challenges posed both to diagnosis and treatment of drug-resistant fungal pathogens.
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Affiliation(s)
| | - Ian Macreadie
- School of Science, RMIT University, Melbourne, VIC, Australia
| | - C. Orla Morrissey
- Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, VIC, Australia
| | - Kylie J. Boyce
- School of Science, RMIT University, Melbourne, VIC, Australia
- Corresponding author. E-mail:
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Phosphoproteomic responses of TORC1 target kinases reveal discrete and convergent mechanisms that orchestrate the quiescence program in yeast. Cell Rep 2021; 37:110149. [PMID: 34965436 DOI: 10.1016/j.celrep.2021.110149] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/19/2021] [Accepted: 11/30/2021] [Indexed: 01/18/2023] Open
Abstract
The eukaryotic TORC1 kinase assimilates diverse environmental cues, including growth factors and nutrients, to control growth by tuning anabolic and catabolic processes. In yeast, TORC1 stimulates protein synthesis in response to abundant nutrients primarily through its proximal effector kinase Sch9. Conversely, TORC1 inhibition following nutrient limitation unlocks various distally controlled kinases (e.g., Atg1, Gcn2, Npr1, Rim15, Slt2/Mpk1, and Yak1), which cooperate through poorly defined circuits to orchestrate the quiescence program. To better define the signaling landscape of the latter kinases, we use in vivo quantitative phosphoproteomics. Through pinpointing known and uncharted Npr1, Rim15, Slt2/Mpk1, and Yak1 effectors, our study examines the architecture of the distally controlled TORC1 kinase network. Accordingly, this is built on a combination of discrete, convergent, and multilayered feedback regulatory mechanisms, which likely ensure homeostatic control of and/or robust responses by TORC1 and its effector kinases under fluctuating nutritional conditions.
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González Montoro A, Vargas Duarte P, Auffarth K, Walter S, Fröhlich F, Ungermann C. Subunit exchange among endolysosomal tethering complexes is linked to contact site formation at the vacuole. Mol Biol Cell 2021; 32:br14. [PMID: 34668759 PMCID: PMC8694092 DOI: 10.1091/mbc.e21-05-0227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The hexameric HOPS (homotypic fusion and protein sorting) complex is a conserved tethering complex at the lysosome-like vacuole, where it mediates tethering and promotes all fusion events involving this organelle. The Vps39 subunit of this complex also engages in a membrane contact site between the vacuole and the mitochondria, called vCLAMP. Additionally, four subunits of HOPS are also part of the endosomal CORVET tethering complex. Here, we analyzed the partition of HOPS and CORVET subunits between the different complexes by tracing their localization and function. We find that Vps39 has a specific role in vCLAMP formation beyond tethering, and that vCLAMPs and HOPS compete for the same pool of Vps39. In agreement, we find that the CORVET subunit Vps3 can take the position of Vps39 in HOPS. This endogenous pool of a Vps3-hybrid complex is affected by Vps3 or Vps39 levels, suggesting that HOPS and CORVET assembly is dynamic. Our data shed light on how individual subunits of tethering complexes such as Vps39 can participate in other functions, while maintaining the remaining subcomplex available for its function in tethering and fusion.
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Affiliation(s)
- Ayelén González Montoro
- Cellular Communication Laboratory, Osnabrück University, 49076 Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, 49076 Osnabrück, Germany
| | | | - Kathrin Auffarth
- Biochemistry section, Osnabrück University, 49076 Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, 49076 Osnabrück, Germany
| | - Florian Fröhlich
- Molecular Membrane Biology section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry section, Osnabrück University, 49076 Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), Osnabrück University, 49076 Osnabrück, Germany
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Hu G, Bakkeren E, Caza M, Horianopoulos L, Sánchez-León E, Sorensen M, Jung W, Kronstad JW. Vam6/Vps39/TRAP1-domain proteins influence vacuolar morphology, iron acquisition and virulence in Cryptococcus neoformans. Cell Microbiol 2021; 23:e13400. [PMID: 34800311 DOI: 10.1111/cmi.13400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 11/05/2021] [Accepted: 11/16/2021] [Indexed: 12/21/2022]
Abstract
The pathogenic fungus Cryptococcus neoformans must overcome iron limitation to cause disease in mammalian hosts. Previously, we reported a screen for insertion mutants with poor growth on haem as the sole iron source. In this study, we characterised one such mutant and found that the defective gene encoded a Vam6/Vps39/TRAP1 domain-containing protein required for robust growth on haem, an important iron source in host tissue. We designated this protein Vps3 based on reciprocal best matches with the corresponding protein in Saccharomyces cerevisiae. C. neoformans encodes a second Vam6/Vps39/TRAP1 domain-containing protein designated Vam6/Vlp1, and we found that this protein is also required for robust growth on haem as well as on inorganic iron sources. This protein is predicted to be a component of the homotypic fusion and vacuole protein sorting complex involved in endocytosis. Further characterisation of the vam6Δ and vps3Δ mutants revealed perturbed trafficking of iron acquisition functions (e.g., the high affinity iron permease Cft1) and impaired processing of the transcription factor Rim101, a regulator of haem and iron acquisition. The vps3Δ and vam6Δ mutants also had pleiotropic phenotypes including loss of virulence in a mouse model of cryptococcosis, reduced virulence factor elaboration and increased susceptibility to stress, indicating pleiotropic roles for Vps3 and Vam6 beyond haem use in C. neoformans. TAKE AWAYS: Two Vam6/Vps39/TRAP1-domain proteins, Vps3 and Vam6, support the growth of Cryptococcus neoformans on haem. Loss of Vps3 and Vam6 influences the trafficking and expression of iron uptake proteins. Loss of Vps3 or Vam6 eliminates the ability of C. neoformans to cause disease in a mouse model of cryptococcosis.
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Affiliation(s)
- Guanggan Hu
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erik Bakkeren
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Zoology, University of Oxford, Oxford, UK
| | - Mélissa Caza
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.,Larissa Yarr Medical Microbiology Laboratory, Kelowna General Hospital, Kelowna, British Columbia, Canada
| | - Linda Horianopoulos
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eddy Sánchez-León
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Melanie Sorensen
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wonhee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, Republic of Korea
| | - James W Kronstad
- The Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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Calvo IA, Sharma S, Paulo JA, Gulka AO, Boeszoermenyi A, Zhang J, Lombana JM, Palmieri CM, Laviolette LA, Arthanari H, Iliopoulos O, Gygi SP, Motamedi M. The fission yeast FLCN/FNIP complex augments TORC1 repression or activation in response to amino acid (AA) availability. iScience 2021; 24:103338. [PMID: 34805795 PMCID: PMC8590082 DOI: 10.1016/j.isci.2021.103338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/10/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The target of Rapamycin complex1 (TORC1) senses and integrates several environmental signals, including amino acid (AA) availability, to regulate cell growth. Folliculin (FLCN) is a tumor suppressor (TS) protein in renal cell carcinoma, which paradoxically activates TORC1 in response to AA supplementation. Few tractable systems for modeling FLCN as a TS are available. Here, we characterize the FLCN-containing complex in Schizosaccharomyces pombe (called BFC) and show that BFC augments TORC1 repression and activation in response to AA starvation and supplementation, respectively. BFC co-immunoprecipitates V-ATPase, a TORC1 modulator, and regulates its activity in an AA-dependent manner. BFC genetic and proteomic networks identify the conserved peptide transmembrane transporter Ptr2 and the phosphoribosylformylglycinamidine synthase Ade3 as new AA-dependent regulators of TORC1. Overall, these data ascribe an additional repressive function to Folliculin in TORC1 regulation and reveal S. pombe as an excellent system for modeling the AA-dependent, FLCN-mediated repression of TORC1 in eukaryotes.
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Affiliation(s)
- Isabel A. Calvo
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Shalini Sharma
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Alexander O.D. Gulka
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Andras Boeszoermenyi
- Department of Biochemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
- Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Jingyu Zhang
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Jose M. Lombana
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Christina M. Palmieri
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Laura A. Laviolette
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
| | - Haribabu Arthanari
- Department of Biochemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
- Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Othon Iliopoulos
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
- Division of Hematology-Oncology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Mo Motamedi
- Massachusetts General Hospital Center for Cancer Research and Department of Medicine Harvard Medical School, Charlestown, MA 02129, USA
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62
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Zhang S, Lin X, Hou Q, Hu Z, Wang Y, Wang Z. Regulation of mTORC1 by amino acids in mammalian cells: A general picture of recent advances. ACTA ACUST UNITED AC 2021; 7:1009-1023. [PMID: 34738031 PMCID: PMC8536509 DOI: 10.1016/j.aninu.2021.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 05/13/2021] [Accepted: 05/18/2021] [Indexed: 12/11/2022]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) integrates various types of signal inputs, such as energy, growth factors, and amino acids to regulate cell growth and proliferation mainly through the 2 direct downstream targets, eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) and ribosomal protein S6 kinase 1 (S6K1). Most of the signal arms upstream of mTORC1 including energy status, stress signals, and growth factors converge on the tuberous sclerosis complex (TSC) - Ras homologue enriched in brain (Rheb) axis. Amino acids, however, are distinct from other signals and modulate mTORC1 using a unique pathway. In recent years, the transmission mechanism of amino acid signals upstream of mTORC1 has been gradually elucidated, and some sensors or signal transmission pathways for individual amino acids have also been discovered. With the help of these findings, we propose a general picture of recent advances, which demonstrates that various amino acids from lysosomes, cytoplasm, and Golgi are sensed by their respective sensors. These signals converge on mTORC1 and form a huge and complicated signal network with multiple synergies, antagonisms, and feedback mechanisms.
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Affiliation(s)
- Shizhe Zhang
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
| | - Xueyan Lin
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
| | - Qiuling Hou
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
| | - Zhiyong Hu
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
| | - Yun Wang
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
| | - Zhonghua Wang
- Key Laboratory of Ruminant Nutrition and Physiology, College of Animal Science and Technology, Shandong Agricultural University, No. 61, Daizong Street, Tai'an, Shandong, China
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63
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Cdk8 Kinase Module: A Mediator of Life and Death Decisions in Times of Stress. Microorganisms 2021; 9:microorganisms9102152. [PMID: 34683473 PMCID: PMC8540245 DOI: 10.3390/microorganisms9102152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 01/18/2023] Open
Abstract
The Cdk8 kinase module (CKM) of the multi-subunit mediator complex plays an essential role in cell fate decisions in response to different environmental cues. In the budding yeast S. cerevisiae, the CKM consists of four conserved subunits (cyclin C and its cognate cyclin-dependent kinase Cdk8, Med13, and Med12) and predominantly negatively regulates a subset of stress responsive genes (SRG’s). Derepression of these SRG’s is accomplished by disassociating the CKM from the mediator, thus allowing RNA polymerase II-directed transcription. In response to cell death stimuli, cyclin C translocates to the mitochondria where it induces mitochondrial hyper-fission and promotes regulated cell death (RCD). The nuclear release of cyclin C requires Med13 destruction by the ubiquitin-proteasome system (UPS). In contrast, to protect the cell from RCD following SRG induction induced by nutrient deprivation, cyclin C is rapidly destroyed by the UPS before it reaches the cytoplasm. This enables a survival response by two mechanisms: increased ATP production by retaining reticular mitochondrial morphology and relieving CKM-mediated repression on autophagy genes. Intriguingly, nitrogen starvation also stimulates Med13 destruction but through a different mechanism. Rather than destruction via the UPS, Med13 proteolysis occurs in the vacuole (yeast lysosome) via a newly identified Snx4-assisted autophagy pathway. Taken together, these findings reveal that the CKM regulates cell fate decisions by both transcriptional and non-transcriptional mechanisms, placing it at a convergence point between cell death and cell survival pathways.
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64
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Loissell-Baltazar YA, Dokudovskaya S. SEA and GATOR 10 Years Later. Cells 2021; 10:cells10102689. [PMID: 34685669 PMCID: PMC8534245 DOI: 10.3390/cells10102689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 12/17/2022] Open
Abstract
The SEA complex was described for the first time in yeast Saccharomyces cerevisiae ten years ago, and its human homologue GATOR complex two years later. During the past decade, many advances on the SEA/GATOR biology in different organisms have been made that allowed its role as an essential upstream regulator of the mTORC1 pathway to be defined. In this review, we describe these advances in relation to the identification of multiple functions of the SEA/GATOR complex in nutrient response and beyond and highlight the consequence of GATOR mutations in cancer and neurodegenerative diseases.
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65
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Megarioti AH, Primo C, Kapetanakis GC, Athanasopoulos A, Sophianopoulou V, André B, Gournas C. The Bul1/2 Alpha-Arrestins Promote Ubiquitylation and Endocytosis of the Can1 Permease upon Cycloheximide-Induced TORC1-Hyperactivation. Int J Mol Sci 2021; 22:10208. [PMID: 34638549 PMCID: PMC8508209 DOI: 10.3390/ijms221910208] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/12/2022] Open
Abstract
Selective endocytosis followed by degradation is a major mechanism for downregulating plasma membrane transporters in response to specific environmental cues. In Saccharomyces cerevisiae, this endocytosis is promoted by ubiquitylation catalyzed by the Rsp5 ubiquitin-ligase, targeted to transporters via adaptors of the alpha-arrestin family. However, the molecular mechanisms of this targeting and their control according to conditions remain incompletely understood. In this work, we dissect the molecular mechanisms eliciting the endocytosis of Can1, the arginine permease, in response to cycloheximide-induced TORC1 hyperactivation. We show that cycloheximide promotes Rsp5-dependent Can1 ubiquitylation and endocytosis in a manner dependent on the Bul1/2 alpha-arrestins. Also crucial for this downregulation is a short acidic patch sequence in the N-terminus of Can1 likely acting as a binding site for Bul1/2. The previously reported inhibition by cycloheximide of transporter recycling, from the trans-Golgi network to the plasma membrane, seems to additionally contribute to efficient Can1 downregulation. Our results also indicate that, contrary to the previously described substrate-transport elicited Can1 endocytosis mediated by the Art1 alpha-arrestin, Bul1/2-mediated Can1 ubiquitylation occurs independently of the conformation of the transporter. This study provides further insights into how distinct alpha-arrestins control the ubiquitin-dependent downregulation of a specific amino acid transporter under different conditions.
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Affiliation(s)
- Amalia H. Megarioti
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Patr. Grigoriou E & 27 Neapoleos St., 15341 Agia Paraskevi, Greece; (A.H.M.); (A.A.); (V.S.)
| | - Cecilia Primo
- Molecular Physiology of the Cell Laboratory, Université Libre de Bruxelles (ULB), IBMM, 6041 Gosselies, Belgium; (C.P.); (G.C.K.)
| | - George C. Kapetanakis
- Molecular Physiology of the Cell Laboratory, Université Libre de Bruxelles (ULB), IBMM, 6041 Gosselies, Belgium; (C.P.); (G.C.K.)
| | - Alexandros Athanasopoulos
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Patr. Grigoriou E & 27 Neapoleos St., 15341 Agia Paraskevi, Greece; (A.H.M.); (A.A.); (V.S.)
| | - Vicky Sophianopoulou
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Patr. Grigoriou E & 27 Neapoleos St., 15341 Agia Paraskevi, Greece; (A.H.M.); (A.A.); (V.S.)
| | - Bruno André
- Molecular Physiology of the Cell Laboratory, Université Libre de Bruxelles (ULB), IBMM, 6041 Gosselies, Belgium; (C.P.); (G.C.K.)
| | - Christos Gournas
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Patr. Grigoriou E & 27 Neapoleos St., 15341 Agia Paraskevi, Greece; (A.H.M.); (A.A.); (V.S.)
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66
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Tanigawa M, Yamamoto K, Nagatoishi S, Nagata K, Noshiro D, Noda NN, Tsumoto K, Maeda T. A glutamine sensor that directly activates TORC1. Commun Biol 2021; 4:1093. [PMID: 34535752 PMCID: PMC8448839 DOI: 10.1038/s42003-021-02625-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 08/31/2021] [Indexed: 01/08/2023] Open
Abstract
TOR complex 1 (TORC1) is an evolutionarily-conserved protein kinase that controls cell growth and metabolism in response to nutrients, particularly amino acids. In mammals, several amino acid sensors have been identified that converge on the multi-layered machinery regulating Rag GTPases to trigger TORC1 activation; however, these sensors are not conserved in many other organisms including yeast. Previously, we reported that glutamine activates yeast TORC1 via a Gtr (Rag ortholog)-independent mechanism involving the vacuolar protein Pib2, although the identity of the supposed glutamine sensor and the exact TORC1 activation mechanism remain unclear. In this study, we successfully reconstituted glutamine-responsive TORC1 activation in vitro using only purified Pib2 and TORC1. In addition, we found that glutamine specifically induced a change in the folding state of Pib2. These findings indicate that Pib2 is a glutamine sensor that directly activates TORC1, providing a new model for the metabolic control of cells.
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Affiliation(s)
- Mirai Tanigawa
- Departments of Biology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Katsuyoshi Yamamoto
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Satoru Nagatoishi
- The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Koji Nagata
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | | | - Nobuo N Noda
- Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan
| | - Kouhei Tsumoto
- The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Tatsuya Maeda
- Departments of Biology, Hamamatsu University School of Medicine, Shizuoka, Japan. .,Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.
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67
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Diphthamide promotes TOR signaling by increasing the translation of proteins in the TORC1 pathway. Proc Natl Acad Sci U S A 2021; 118:2104577118. [PMID: 34507998 PMCID: PMC8449394 DOI: 10.1073/pnas.2104577118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2021] [Indexed: 01/31/2023] Open
Abstract
Diphthamide, a modification found only on translation elongation factor 2 (EF2), was proposed to suppress -1 frameshifting in translation. Although diphthamide is conserved among all eukaryotes, exactly what proteins are affected by diphthamide deletion is not clear in cells. Through genome-wide profiling for a potential -1 frameshifting site, we identified that the target of rapamycin complex 1 (TORC1)/mammalian TORC1 (mTORC1) signaling pathway is affected by deletion of diphthamide. Diphthamide deficiency in yeast suppresses the translation of TORC1-activating proteins Vam6 and Rtc1. Interestingly, TORC1 signaling also promotes diphthamide biosynthesis, suggesting that diphthamide forms a positive feedback loop to promote translation under nutrient-rich conditions. Our results provide an explanation for why diphthamide is evolutionarily conserved and why diphthamide deletion can cause severe developmental defects.
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68
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Jin J, Kim C, Xia Q, Gould TM, Cao W, Zhang H, Li X, Weiskopf D, Grifoni A, Sette A, Weyand CM, Goronzy JJ. Activation of mTORC1 at late endosomes misdirects T cell fate decision in older individuals. Sci Immunol 2021; 6:eabg0791. [PMID: 34145066 PMCID: PMC8422387 DOI: 10.1126/sciimmunol.abg0791] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 05/18/2021] [Indexed: 12/11/2022]
Abstract
The nutrient-sensing mammalian target of rapamycin (mTOR) is integral to cell fate decisions after T cell activation. Sustained mTORC1 activity favors the generation of terminally differentiated effector T cells instead of follicular helper and memory T cells. This is particularly pertinent for T cell responses of older adults who have sustained mTORC1 activation despite dysfunctional lysosomes. Here, we show that lysosome-deficient T cells rely on late endosomes rather than lysosomes as an mTORC1 activation platform, where mTORC1 is activated by sensing cytosolic amino acids. T cells from older adults have an increased expression of the plasma membrane leucine transporter SLC7A5 to provide a cytosolic amino acid source. Hence, SLC7A5 and VPS39 deficiency (a member of the HOPS complex promoting early to late endosome conversion) substantially reduced mTORC1 activities in T cells from older but not young individuals. Late endosomal mTORC1 is independent of the negative-feedback loop involving mTORC1-induced inactivation of the transcription factor TFEB that controls expression of lysosomal genes. The resulting sustained mTORC1 activation impaired lysosome function and prevented lysosomal degradation of PD-1 in CD4+ T cells from older adults, thereby inhibiting their proliferative responses. VPS39 silencing of human T cells improved their expansion to pertussis and to SARS-CoV-2 peptides in vitro. Furthermore, adoptive transfer of CD4+ Vps39-deficient LCMV-specific SMARTA cells improved germinal center responses, CD8+ memory T cell generation, and recall responses to infection. Thus, curtailing late endosomal mTORC1 activity is a promising strategy to enhance T cell immunity.
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Affiliation(s)
- Jun Jin
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Chulwoo Kim
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Qiong Xia
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Timothy M Gould
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Wenqiang Cao
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Huimin Zhang
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Xuanying Li
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Daniela Weiskopf
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Alba Grifoni
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Alessandro Sette
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA, USA
- Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, La Jolla, CA, USA
| | - Cornelia M Weyand
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
| | - Jorg J Goronzy
- Division of Immunology and Rheumatology, Department of Medicine, Stanford University, Stanford, CA, USA.
- Department of Medicine, Palo Alto Veterans Administration Healthcare System, Palo Alto, CA, United States
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69
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Tate JJ, Rai R, De Virgilio C, Cooper TG. N- and C-terminal Gln3-Tor1 interaction sites: one acting negatively and the other positively to regulate nuclear Gln3 localization. Genetics 2021; 217:iyab017. [PMID: 33857304 PMCID: PMC8049557 DOI: 10.1093/genetics/iyab017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/24/2021] [Indexed: 12/31/2022] Open
Abstract
Gln3 activates Nitrogen Catabolite Repression, NCR-sensitive expression of the genes required for Saccharomyces cerevisiae to scavenge poor nitrogen sources from its environment. The global TorC1 kinase complex negatively regulates nuclear Gln3 localization, interacting with an α-helix in the C-terminal region of Gln3, Gln3656-666. In nitrogen replete conditions, Gln3 is sequestered in the cytoplasm, whereas when TorC1 is down-regulated, in nitrogen restrictive conditions, Gln3 migrates into the nucleus. In this work, we show that the C-terminal Gln3-Tor1 interaction site is required for wild type, rapamycin-elicited, Sit4-dependent nuclear Gln3 localization, but not for its dephosphorylation. In fact, truncated Gln31-384 can enter the nucleus in the absence of Sit4 in both repressive and derepressive growth conditions. However, Gln31-384 can only enter the nucleus if a newly discovered second positively-acting Gln3-Tor1 interaction site remains intact. Importantly, the N- and C-terminal Gln3-Tor1 interaction sites function both autonomously and collaboratively. The N-terminal Gln3-Tor1 interaction site, previously designated Gln3URS contains a predicted α-helix situated within an unstructured coiled-coil region. Eight of the thirteen serine/threonine residues in the Gln3URS are dephosphorylated 3-15-fold with three of them by 10-15-fold. Substituting phosphomimetic aspartate for serine/threonine residues in the Gln3 URS abolishes the N-terminal Gln3-Tor1 interaction, rapamycin-elicited nuclear Gln3 localization, and ½ of the derepressed levels of nuclear Gln3 localization. Cytoplasmic Gln3 sequestration in repressive conditions, however, remains intact. These findings further deconvolve the mechanisms that achieve nitrogen-responsive transcription factor regulation downstream of TorC1.
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Affiliation(s)
- Jennifer J Tate
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Rajendra Rai
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | | | - Terrance G Cooper
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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70
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Chang Y, Lim G, Huh WK. Analysis of the TORC1 interactome reveals a spatially distinct function of TORC1 in mRNP complexes. J Cell Biol 2021; 220:211781. [PMID: 33566094 PMCID: PMC7879482 DOI: 10.1083/jcb.201912060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 11/15/2020] [Accepted: 01/06/2021] [Indexed: 11/22/2022] Open
Abstract
The target of rapamycin complex 1 (TORC1) is mainly localized to the vacuolar membrane and regulates eukaryotic cell growth in response to nutrient availability. To obtain deeper insights into the functional roles of TORC1, we performed a genome-wide analysis of the TORC1 interactome in yeast using the bimolecular fluorescence complementation (BiFC) assay. We found that while most of the BiFC signals are observed at the vacuolar membrane, a fraction of them are detected at cytoplasmic messenger ribonucleoprotein (mRNP) granules. Moreover, mRNA-binding proteins are enriched in the TORC1 interactome, suggesting a functional relationship between TORC1 and mRNA metabolism. We show that a portion of TORC1 is consistently associated with mRNP complexes and interacts with a specific subset of mRNAs. We also demonstrate that TORC1 directly targets a translational repressor Scd6 and that the activity of Scd6 is inhibited by TORC1-dependent phosphorylation. Collectively, our data suggest that TORC1 plays a novel role in posttranscriptional regulation by controlling the activity of Scd6.
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Affiliation(s)
- Yeonji Chang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.,Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
| | - Gyubum Lim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Won-Ki Huh
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.,Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
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71
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Österberg L, Domenzain I, Münch J, Nielsen J, Hohmann S, Cvijovic M. A novel yeast hybrid modeling framework integrating Boolean and enzyme-constrained networks enables exploration of the interplay between signaling and metabolism. PLoS Comput Biol 2021; 17:e1008891. [PMID: 33836000 PMCID: PMC8059808 DOI: 10.1371/journal.pcbi.1008891] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/21/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
The interplay between nutrient-induced signaling and metabolism plays an important role in maintaining homeostasis and its malfunction has been implicated in many different human diseases such as obesity, type 2 diabetes, cancer, and neurological disorders. Therefore, unraveling the role of nutrients as signaling molecules and metabolites together with their interconnectivity may provide a deeper understanding of how these conditions occur. Both signaling and metabolism have been extensively studied using various systems biology approaches. However, they are mainly studied individually and in addition, current models lack both the complexity of the dynamics and the effects of the crosstalk in the signaling system. To gain a better understanding of the interconnectivity between nutrient signaling and metabolism in yeast cells, we developed a hybrid model, combining a Boolean module, describing the main pathways of glucose and nitrogen signaling, and an enzyme-constrained model accounting for the central carbon metabolism of Saccharomyces cerevisiae, using a regulatory network as a link. The resulting hybrid model was able to capture a diverse utalization of isoenzymes and to our knowledge outperforms constraint-based models in the prediction of individual enzymes for both respiratory and mixed metabolism. The model showed that during fermentation, enzyme utilization has a major contribution in governing protein allocation, while in low glucose conditions robustness and control are prioritized. In addition, the model was capable of reproducing the regulatory effects that are associated with the Crabtree effect and glucose repression, as well as regulatory effects associated with lifespan increase during caloric restriction. Overall, we show that our hybrid model provides a comprehensive framework for the study of the non-trivial effects of the interplay between signaling and metabolism, suggesting connections between the Snf1 signaling pathways and processes that have been related to chronological lifespan of yeast cells.
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Affiliation(s)
- Linnea Österberg
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Iván Domenzain
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
| | - Julia Münch
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, Gothenburg, Sweden
- BioInnovation Institute, Copenhagen, Denmark
| | - Stefan Hohmann
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Marija Cvijovic
- Department of Mathematical Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Mathematical Sciences, Chalmers University of Technology, Gothenburg, Sweden
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72
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Hepowit NL, Macedo JKA, Young LEA, Liu K, Sun RC, MacGurn JA, Dickson RC. Enhancing lifespan of budding yeast by pharmacological lowering of amino acid pools. Aging (Albany NY) 2021; 13:7846-7871. [PMID: 33744865 PMCID: PMC8034917 DOI: 10.18632/aging.202849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/21/2021] [Indexed: 04/20/2023]
Abstract
The increasing prevalence of age-related diseases and resulting healthcare insecurity and emotional burden require novel treatment approaches. Several promising strategies seek to limit nutrients and promote healthy aging. Unfortunately, the human desire to consume food means this strategy is not practical for most people but pharmacological approaches might be a viable alternative. We previously showed that myriocin, which impairs sphingolipid synthesis, increases lifespan in Saccharomyces cerevisiae by modulating signaling pathways including the target of rapamycin complex 1 (TORC1). Since TORC1 senses cellular amino acids, we analyzed amino acid pools and identified 17 that are lowered by myriocin treatment. Studying the methionine transporter, Mup1, we found that newly synthesized Mup1 traffics to the plasma membrane and is stable for several hours but is inactive in drug-treated cells. Activity can be restored by adding phytosphingosine to culture medium thereby bypassing drug inhibition, thus confirming a sphingolipid requirement for Mup1 activity. Importantly, genetic analysis of myriocin-induced longevity revealed a requirement for the Gtr1/2 (mammalian Rags) and Vps34-Pib2 amino acid sensing pathways upstream of TORC1, consistent with a mechanism of action involving decreased amino acid availability. These studies demonstrate the feasibility of pharmacologically inducing a state resembling amino acid restriction to promote healthy aging.
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Affiliation(s)
- Nathaniel L. Hepowit
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jessica K. A. Macedo
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Lyndsay E. A. Young
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Ke Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, Sichuan University, Chengdu 610000, Sichuan, P. R. China
| | - Ramon C. Sun
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536, USA
| | - Jason A. MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Robert C. Dickson
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40536, USA
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73
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Global phosphoproteomics pinpoints uncharted Gcn2-mediated mechanisms of translational control. Mol Cell 2021; 81:1879-1889.e6. [PMID: 33743194 DOI: 10.1016/j.molcel.2021.02.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/09/2020] [Accepted: 02/24/2021] [Indexed: 01/04/2023]
Abstract
The conserved Gcn2 protein kinase mediates cellular adaptations to amino acid limitation through translational control of gene expression that is exclusively executed by phosphorylation of the α-subunit of the eukaryotic translation initiation factor 2 (eIF2α). Using quantitative phosphoproteomics, however, we discovered that Gcn2 targets auxiliary effectors to modulate translation. Accordingly, Gcn2 also phosphorylates the β-subunit of the trimeric eIF2 G protein complex to promote its association with eIF5, which prevents spontaneous nucleotide exchange on eIF2 and thereby restricts the recycling of the initiator methionyl-tRNA-bound eIF2-GDP ternary complex in amino-acid-starved cells. This mechanism contributes to the inhibition of translation initiation in parallel to the sequestration of the nucleotide exchange factor eIF2B by phosphorylated eIF2α. Gcn2 further phosphorylates Gcn20 to antagonize, in an inhibitory feedback loop, the formation of the Gcn2-stimulatory Gcn1-Gcn20 complex. Thus, Gcn2 plays a substantially more intricate role in controlling translation initiation than hitherto appreciated.
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74
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Dai J, Xia H, Yang C, Chen X. Sensing, Uptake and Catabolism of L-Phenylalanine During 2-Phenylethanol Biosynthesis via the Ehrlich Pathway in Saccharomyces cerevisiae. Front Microbiol 2021; 12:601963. [PMID: 33717002 PMCID: PMC7947893 DOI: 10.3389/fmicb.2021.601963] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 01/29/2021] [Indexed: 01/15/2023] Open
Abstract
2-Phenylethanol (2-PE) is an important flavouring ingredient with a persistent rose-like odour, and it has been widely utilized in food, perfume, beverages, and medicine. Due to the potential existence of toxic byproducts in 2-PE resulting from chemical synthesis, the demand for “natural” 2-PE through biotransformation is increasing. L-Phenylalanine (L-Phe) is used as the precursor for the biosynthesis of 2-PE through the Ehrlich pathway by Saccharomyces cerevisiae. The regulation of L-Phe metabolism in S. cerevisiae is complicated and elaborate. We reviewed current progress on the signal transduction pathways of L-Phe sensing, uptake of extracellular L-Phe and 2-PE synthesis from L-Phe through the Ehrlich pathway. Moreover, the anticipated bottlenecks and future research directions for S. cerevisiae biosynthesis of 2-PE are discussed.
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Affiliation(s)
- Jun Dai
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China.,ABI Group, College of Marine Science and Technology, Zhejiang Ocean University, Zhoushan, China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Huili Xia
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China
| | - Chunlei Yang
- Tobacco Research Institute of Hubei Province, Wuhan, China
| | - Xiong Chen
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, College of Bioengineering, Hubei University of Technology, Wuhan, China
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75
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Indole-3-acetic acid is a physiological inhibitor of TORC1 in yeast. PLoS Genet 2021; 17:e1009414. [PMID: 33690632 PMCID: PMC7978357 DOI: 10.1371/journal.pgen.1009414] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/19/2021] [Accepted: 02/11/2021] [Indexed: 01/13/2023] Open
Abstract
Indole-3-acetic acid (IAA) is the most common, naturally occurring phytohormone that regulates cell division, differentiation, and senescence in plants. The capacity to synthesize IAA is also widespread among plant-associated bacterial and fungal species, which may use IAA as an effector molecule to define their relationships with plants or to coordinate their physiological behavior through cell-cell communication. Fungi, including many species that do not entertain a plant-associated life style, are also able to synthesize IAA, but the physiological role of IAA in these fungi has largely remained enigmatic. Interestingly, in this context, growth of the budding yeast Saccharomyces cerevisiae is sensitive to extracellular IAA. Here, we use a combination of various genetic approaches including chemical-genetic profiling, SAturated Transposon Analysis in Yeast (SATAY), and genetic epistasis analyses to identify the mode-of-action by which IAA inhibits growth in yeast. Surprisingly, these analyses pinpointed the target of rapamycin complex 1 (TORC1), a central regulator of eukaryotic cell growth, as the major growth-limiting target of IAA. Our biochemical analyses further demonstrate that IAA inhibits TORC1 both in vivo and in vitro. Intriguingly, we also show that yeast cells are able to synthesize IAA and specifically accumulate IAA upon entry into stationary phase. Our data therefore suggest that IAA contributes to proper entry of yeast cells into a quiescent state by acting as a metabolic inhibitor of TORC1. Auxins are a major group of plant phytohormones that are critical for growth and development. Amongst the auxins, indole-3-acetic acid (IAA) is the most common, naturally occurring phytohormone that regulates cell division, differentiation, and senescence in plants. Interestingly, the capacity to synthesize and secrete IAA is also widespread among fungi, including the budding yeast Saccharomyces cerevisiae, but the role of IAA in fungi has largely remained unknown. Here, we confirm an earlier observation that IAA inhibits growth of budding yeast and show by diverse genetic and biochemical means that IAA restrains budding yeast growth by inhibiting the target of rapamycin complex 1 (TORC1), a highly conserved eukaryotic regulator of growth. Intriguingly, budding yeast cells accumulate IAA specifically when limited for nutrients, which suggests that IAA plays a hitherto unknown physiological role in contributing to the establishment of cellular quiescence by acting as a metabolic inhibitor of TORC1.
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76
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Puschmann R, Loewith R. Resolving the Communication GAPs Upstream of TORC1. Dev Cell 2021; 55:253-254. [PMID: 33171106 DOI: 10.1016/j.devcel.2020.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this issue of Developmental Cell, Yang et al. (2020) report that both nutrient- and growth factor-dependent signaling impinge upon the RAG GTPases which in turn control TSC residency time on the lysosome membrane and ultimately mTORC1 activity.
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Affiliation(s)
- Robert Puschmann
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland; Swiss National Centre for Competence in Research Chemical Biology, Geneva, Switzerland.
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77
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Zhang Z, Cottignie I, Van Zeebroeck G, Thevelein JM. Nutrient transceptors physically interact with the yeast S6/protein kinase B homolog, Sch9, a TOR kinase target. Biochem J 2021; 478:357-375. [PMID: 33394033 PMCID: PMC7850899 DOI: 10.1042/bcj20200722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/04/2020] [Accepted: 01/04/2021] [Indexed: 12/18/2022]
Abstract
Multiple starvation-induced, high-affinity nutrient transporters in yeast function as receptors for activation of the protein kinase A (PKA) pathway upon re-addition of their substrate. We now show that these transceptors may play more extended roles in nutrient regulation. The Gap1 amino acid, Mep2 ammonium, Pho84 phosphate and Sul1 sulfate transceptors physically interact in vitro and in vivo with the PKA-related Sch9 protein kinase, the yeast homolog of mammalian S6 protein kinase and protein kinase B. Sch9 is a phosphorylation target of TOR and well known to affect nutrient-controlled cellular processes, such as growth rate. Mapping with peptide microarrays suggests specific interaction domains in Gap1 for Sch9 binding. Mutagenesis of the major domain affects the upstart of growth upon the addition of L-citrulline to nitrogen-starved cells to different extents but apparently does not affect in vitro binding. It also does not correlate with the drop in L-citrulline uptake capacity or transceptor activation of the PKA target trehalase by the Gap1 mutant forms. Our results reveal a nutrient transceptor-Sch9-TOR axis in which Sch9 accessibility for phosphorylation by TOR may be affected by nutrient transceptor-Sch9 interaction under conditions of nutrient starvation or other environmental challenges.
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Affiliation(s)
- Zhiqiang Zhang
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Ines Cottignie
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Griet Van Zeebroeck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- Center for Microbiology, VIB, Kasteelpark Arenberg 31, B-3001 Leuven-Heverlee, Flanders, Belgium
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78
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Abstract
Sensing and responding to changes in nutrient levels, including those of glucose, lipids, and amino acids, by the body is necessary for survival. Accordingly, perturbations in nutrient sensing are tightly linked with human pathologies, particularly metabolic diseases such as obesity, type 2 diabetes mellitus, and other complications of metabolic syndromes. The conventional view is that amino acids are fundamental elements for protein and peptide synthesis, while recent studies have revealed that amino acids are also important bioactive molecules that play key roles in signaling pathways and metabolic regulation. Different pathways that sense intracellular and extracellular levels of amino acids are integrated and coordinated at the organismal level, and, together, these pathways maintain whole metabolic homeostasis. In this review, we discuss the studies describing how important sensing signals respond to amino acid availability and how these sensing mechanisms modulate metabolic processes, including energy, glucose, and lipid metabolism. We further discuss whether dysregulation of amino acid sensing signals can be targeted to promote metabolic disorders, and discuss how to translate these mechanisms to treat human diseases. This review will help to enhance our overall understanding of the correlation between amino acid sensing and metabolic homeostasis, which have important implications for human health.
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Affiliation(s)
- Xiaoming Hu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Feifan Guo
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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79
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Morozumi Y, Shiozaki K. Conserved and Divergent Mechanisms That Control TORC1 in Yeasts and Mammals. Genes (Basel) 2021; 12:genes12010088. [PMID: 33445779 PMCID: PMC7828246 DOI: 10.3390/genes12010088] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 12/23/2022] Open
Abstract
Target of rapamycin complex 1 (TORC1), a serine/threonine-protein kinase complex highly conserved among eukaryotes, coordinates cellular growth and metabolism with environmental cues, including nutrients and growth factors. Aberrant TORC1 signaling is associated with cancers and various human diseases, and TORC1 also plays a key role in ageing and lifespan, urging current active research on the mechanisms of TORC1 regulation in a variety of model organisms. Identification and characterization of the RAG small GTPases as well as their regulators, many of which are highly conserved from yeast to humans, led to a series of breakthroughs in understanding the molecular bases of TORC1 regulation. Recruitment of mammalian TORC1 (mTORC1) by RAGs to lysosomal membranes is a key step for mTORC1 activation. Interestingly, the RAG GTPases in fission yeast are primarily responsible for attenuation of TORC1 activity on vacuoles, the yeast equivalent of lysosomes. In this review, we summarize our current knowledge about the functions of TORC1 regulators on yeast vacuoles, and illustrate the conserved and divergent mechanisms of TORC1 regulation between yeasts and mammals.
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Affiliation(s)
- Yuichi Morozumi
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan;
- Correspondence: ; Tel.: +81-743-72-5543
| | - Kazuhiro Shiozaki
- Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan;
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
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80
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Yang S, Zhang Y, Ting CY, Bettedi L, Kim K, Ghaniam E, Lilly MA. The Rag GTPase Regulates the Dynamic Behavior of TSC Downstream of Both Amino Acid and Growth Factor Restriction. Dev Cell 2020; 55:272-288.e5. [PMID: 32898476 PMCID: PMC7657977 DOI: 10.1016/j.devcel.2020.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/30/2020] [Accepted: 08/10/2020] [Indexed: 01/09/2023]
Abstract
The dysregulation of the metabolic regulator TOR complex I (TORC1) contributes to a wide array of human pathologies. Tuberous sclerosis complex (TSC) is a potent inhibitor of TORC1. Here, we demonstrate that the Rag GTPase acts in both the amino-acid-sensing and growth factor signaling pathways to control TORC1 activity through the regulation of TSC dynamics in HeLa cells and Drosophila. We find that TSC lysosomal-cytosolic exchange increases in response to both amino acid and growth factor restriction. Moreover, the rate of exchange mirrors TSC function, with depletions of the Rag GTPase blocking TSC lysosomal mobility and rescuing TORC1 activity. Finally, we show that the GATOR2 complex controls the phosphorylation of TSC2, which is essential for TSC exchange. Our data support the model that the amino acid and growth factor signaling pathways converge on the Rag GTPase to inhibit TORC1 activity through the regulation of TSC dynamics.
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Affiliation(s)
- Shu Yang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yingbiao Zhang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chun-Yuan Ting
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lucia Bettedi
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kuikwon Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elena Ghaniam
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mary A Lilly
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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81
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Chen Z, Malia PC, Hatakeyama R, Nicastro R, Hu Z, Péli-Gulli MP, Gao J, Nishimura T, Eskes E, Stefan CJ, Winderickx J, Dengjel J, De Virgilio C, Ungermann C. TORC1 Determines Fab1 Lipid Kinase Function at Signaling Endosomes and Vacuoles. Curr Biol 2020; 31:297-309.e8. [PMID: 33157024 DOI: 10.1016/j.cub.2020.10.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/25/2020] [Accepted: 10/08/2020] [Indexed: 01/17/2023]
Abstract
Organelles of the endomembrane system maintain their identity and integrity during growth or stress conditions by homeostatic mechanisms that regulate membrane flux and biogenesis. At lysosomes and endosomes, the Fab1 lipid kinase complex and the nutrient-regulated target of rapamycin complex 1 (TORC1) control the integrity of the endolysosomal homeostasis and cellular metabolism. Both complexes are functionally connected as Fab1-dependent generation of PI(3,5)P2 supports TORC1 activity. Here, we identify Fab1 as a target of TORC1 on signaling endosomes, which are distinct from multivesicular bodies, and provide mechanistic insight into their crosstalk. Accordingly, TORC1 can phosphorylate Fab1 proximal to its PI3P-interacting FYVE domain, which causes Fab1 to shift to signaling endosomes, where it generates PI(3,5)P2. This, in turn, regulates (1) vacuole morphology, (2) recruitment of TORC1 and the TORC1-regulatory Rag GTPase-containing EGO complex to signaling endosomes, and (3) TORC1 activity. Thus, our study unravels a regulatory feedback loop between TORC1 and the Fab1 complex that controls signaling at endolysosomes.
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Affiliation(s)
- Zilei Chen
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Pedro Carpio Malia
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Riko Hatakeyama
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Zehan Hu
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Marie-Pierre Péli-Gulli
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Jieqiong Gao
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Taki Nishimura
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Elja Eskes
- Functional Biology, KU Leuven, Kasteelpark Arensberg 31, 3000 Leuven, Belgium
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Joris Winderickx
- Functional Biology, KU Leuven, Kasteelpark Arensberg 31, 3000 Leuven, Belgium
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Chemin du Musée, CH-1700 Fribourg, Switzerland.
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany; Center of Cellular Nanoanalytics Osnabrück (CellNanOs), University of Osnabrück, Barbarastrasse 11, 49076 Osnabrück, Germany.
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82
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Mugume Y, Kazibwe Z, Bassham DC. Target of Rapamycin in Control of Autophagy: Puppet Master and Signal Integrator. Int J Mol Sci 2020; 21:ijms21218259. [PMID: 33158137 PMCID: PMC7672647 DOI: 10.3390/ijms21218259] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023] Open
Abstract
The target of rapamycin (TOR) is an evolutionarily-conserved serine/threonine kinase that senses and integrates signals from the environment to coordinate developmental and metabolic processes. TOR senses nutrients, hormones, metabolites, and stress signals to promote cell and organ growth when conditions are favorable. However, TOR is inhibited when conditions are unfavorable, promoting catabolic processes such as autophagy. Autophagy is a macromolecular degradation pathway by which cells degrade and recycle cytoplasmic materials. TOR negatively regulates autophagy through phosphorylation of ATG13, preventing activation of the autophagy-initiating ATG1-ATG13 kinase complex. Here we review TOR complex composition and function in photosynthetic and non-photosynthetic organisms. We also review recent developments in the identification of upstream TOR activators and downstream effectors of TOR. Finally, we discuss recent developments in our understanding of the regulation of autophagy by TOR in photosynthetic organisms.
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83
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Hao P, Yu J, Ward R, Liu Y, Hao Q, An S, Xu T. Eukaryotic translation initiation factors as promising targets in cancer therapy. Cell Commun Signal 2020; 18:175. [PMID: 33148274 PMCID: PMC7640403 DOI: 10.1186/s12964-020-00607-9] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 06/01/2020] [Indexed: 02/08/2023] Open
Abstract
The regulation of the translation of messenger RNA (mRNA) in eukaryotic cells is critical for gene expression, and occurs principally at the initiation phase which is mainly regulated by eukaryotic initiation factors (eIFs). eIFs are fundamental for the translation of mRNA and as such act as the primary targets of several signaling pathways to regulate gene expression. Mis-regulated mRNA expression is a common feature of tumorigenesis and the abnormal activity of eIF complexes triggered by upstream signaling pathways is detected in many tumors, leading to the selective translation of mRNA encoding proteins involved in tumorigenesis, metastasis, or resistance to anti-cancer drugs, and making eIFs a promising therapeutic target for various types of cancers. Here, we briefly outline our current understanding of the biology of eIFs, mainly focusing on the effects of several signaling pathways upon their functions and discuss their contributions to the initiation and progression of tumor growth. An overview of the progress in developing agents targeting the components of translation machinery for cancer treatment is also provided. Video abstract
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Affiliation(s)
- Peiqi Hao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, 727 Jingming South Road, Kunming, 650500, China.,Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Jiaojiao Yu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, 727 Jingming South Road, Kunming, 650500, China
| | - Richard Ward
- Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
| | - Yin Liu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Qiao Hao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China
| | - Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China.
| | - Tianrui Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, 650500, China.
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84
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Hesketh GG, Papazotos F, Pawling J, Rajendran D, Knight JDR, Martinez S, Taipale M, Schramek D, Dennis JW, Gingras AC. The GATOR–Rag GTPase pathway inhibits mTORC1 activation by
lysosome-derived amino acids. Science 2020; 370:351-356. [DOI: 10.1126/science.aaz0863] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 04/18/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) couples nutrient
sufficiency to cell growth. mTORC1 is activated by exogenously acquired
amino acids sensed through the GATOR–Rag guanosine triphosphatase (GTPase)
pathway, or by amino acids derived through lysosomal degradation of protein
by a poorly defined mechanism. Here, we revealed that amino acids derived
from the degradation of protein (acquired through oncogenic Ras-driven
macropinocytosis) activate mTORC1 by a Rag GTPase–independent mechanism.
mTORC1 stimulation through this pathway required the HOPS complex and was
negatively regulated by activation of the GATOR-Rag GTPase pathway.
Therefore, distinct but functionally coordinated pathways control mTORC1
activity on late endocytic organelles in response to distinct sources of
amino acids.
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Affiliation(s)
- Geoffrey G. Hesketh
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Fotini Papazotos
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Judy Pawling
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Dushyandi Rajendran
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - James D. R. Knight
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Sebastien Martinez
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
| | - Mikko Taipale
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada
| | - Daniel Schramek
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - James W. Dennis
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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85
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Chen H, Miller PW, Johnson DL, Laribee RN. The Ccr4-Not complex regulates TORC1 signaling and mitochondrial metabolism by promoting vacuole V-ATPase activity. PLoS Genet 2020; 16:e1009046. [PMID: 33064727 PMCID: PMC7592917 DOI: 10.1371/journal.pgen.1009046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 10/28/2020] [Accepted: 08/12/2020] [Indexed: 01/30/2023] Open
Abstract
The Ccr4-Not complex functions as an effector of multiple signaling pathways that control gene transcription and mRNA turnover. Consequently, Ccr4-Not contributes to a diverse array of processes, which includes a significant role in cell metabolism. Yet a mechanistic understanding of how it contributes to metabolism is lacking. Herein, we provide evidence that Ccr4-Not activates nutrient signaling through the essential target of rapamycin complex 1 (TORC1) pathway. Ccr4-Not disruption reduces global TORC1 signaling, and it also upregulates expression of the cell wall integrity (CWI) pathway terminal kinase Mpk1. Although CWI signaling represses TORC1 signaling, we find that Ccr4-Not loss inhibits TORC1 independently of CWI activation. Instead, we demonstrate that Ccr4-Not promotes the function of the vacuole V-ATPase, which interacts with the Gtr1 GTPase-containing EGO complex to stimulate TORC1 in response to nutrient sufficiency. Bypassing the V-ATPase requirement in TORC1 activation using a constitutively active Gtr1 mutant fully restores TORC1 signaling in Ccr4-Not deficient cells. Transcriptome analysis and functional studies revealed that loss of the Ccr4 subunit activates the TORC1 repressed retrograde signaling pathway to upregulate mitochondrial activity. Blocking this mitochondrial upregulation in Ccr4-Not deficient cells further represses TORC1 signaling, and it causes synergistic deficiencies in mitochondrial-dependent metabolism. These data support a model whereby Ccr4-Not loss impairs V-ATPase dependent TORC1 activation that forces cells to enhance mitochondrial metabolism to sustain a minimal level of TORC1 signaling necessary for cell growth and proliferation. Therefore, Ccr4-Not plays an integral role in nutrient signaling and cell metabolism by promoting V-ATPase dependent TORC1 activation.
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Affiliation(s)
- Hongfeng Chen
- Department of Pathology and Laboratory Medicine, College of Medicine and the Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - P. Winston Miller
- Molecular Bioinformatics Core and the University of Tennessee Health Science Center Office of Research, University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - Daniel L. Johnson
- Molecular Bioinformatics Core and the University of Tennessee Health Science Center Office of Research, University of Tennessee Health Science Center, Memphis, TN, United States of America
| | - R. Nicholas Laribee
- Department of Pathology and Laboratory Medicine, College of Medicine and the Center for Cancer Research, University of Tennessee Health Science Center, Memphis, TN, United States of America
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86
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Uemura S, Mochizuki T, Amemiya K, Kurosaka G, Yazawa M, Nakamoto K, Ishikawa Y, Izawa S, Abe F. Amino acid homeostatic control by TORC1 in Saccharomyces cerevisiae under high hydrostatic pressure. J Cell Sci 2020; 133:jcs245555. [PMID: 32801125 DOI: 10.1242/jcs.245555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/05/2020] [Indexed: 12/30/2022] Open
Abstract
Mechanical stresses, including high hydrostatic pressure, elicit diverse physiological effects on organisms. Gtr1, Gtr2, Ego1 (also known as Meh1) and Ego3 (also known as Slm4), central regulators of the TOR complex 1 (TORC1) nutrient signaling pathway, are required for the growth of Saccharomyces cerevisiae cells under high pressure. Here, we showed that a pressure of 25 MPa (∼250 kg/cm2) stimulates TORC1 to promote phosphorylation of Sch9, which depends on the EGO complex (EGOC) and Pib2. Incubation of cells at this pressure aberrantly increased glutamine and alanine levels in the ego1Δ, gtr1Δ, tor1Δ and pib2Δ mutants, whereas the polysome profiles were unaffected. Moreover, we found that glutamine levels were reduced by combined deletions of EGO1, GTR1, TOR1 and PIB2 with GLN3 These results suggest that high pressure leads to the intracellular accumulation of amino acids. Subsequently, Pib2 loaded with glutamine stimulates the EGOC-TORC1 complex to inactivate Gln3, downregulating glutamine synthesis. Our findings illustrate the regulatory circuit that maintains intracellular amino acid homeostasis and suggest critical roles for the EGOC-TORC1 and Pib2-TORC1 complexes in the growth of yeast under high hydrostatic pressure.
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Affiliation(s)
- Satoshi Uemura
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
- Division of Medical Biochemistry, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, 1-15-1, Fukumuro, Miyagino-ku, Sendai, Miyagi 983-8536, Japan
| | - Takahiro Mochizuki
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
| | - Kengo Amemiya
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
| | - Goyu Kurosaka
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
| | - Miho Yazawa
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
| | - Keiko Nakamoto
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
| | - Yu Ishikawa
- Laboratory of Microbial Technology, Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Shingo Izawa
- Laboratory of Microbial Technology, Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Fumiyoshi Abe
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Japan
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87
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Otsubo Y, Kamada Y, Yamashita A. Novel Links between TORC1 and Traditional Non-Coding RNA, tRNA. Genes (Basel) 2020; 11:E956. [PMID: 32825021 PMCID: PMC7563549 DOI: 10.3390/genes11090956] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022] Open
Abstract
Target of rapamycin (TOR) is a serine/threonine kinase that modulates cell growth and metabolism in response to environmental changes. Transfer RNA (tRNA) is an abundant and ubiquitous small non-coding RNA that is essential in the translation of mRNAs. Beyond its canonical role, it has been revealed that tRNAs have more diverse functions. TOR complex 1 (TORC1), which is one of the two TOR complexes, regulates tRNA synthesis by controlling RNA polymerase III. In addition to tRNA synthesis regulation, recent studies have revealed hidden connections between TORC1 and tRNA, which are both essential players in eukaryotic cellular activities. Here, we review the accumulating findings on the regulatory links between TORC1 and tRNA-particularly those links in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe.
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Affiliation(s)
- Yoko Otsubo
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yoshiaki Kamada
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Akira Yamashita
- National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan; (Y.O.); (Y.K.)
- Center for Novel Science Initiatives, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
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88
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Takahara T, Amemiya Y, Sugiyama R, Maki M, Shibata H. Amino acid-dependent control of mTORC1 signaling: a variety of regulatory modes. J Biomed Sci 2020; 27:87. [PMID: 32799865 PMCID: PMC7429791 DOI: 10.1186/s12929-020-00679-2] [Citation(s) in RCA: 163] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/30/2020] [Indexed: 01/10/2023] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) is an essential regulator of cell growth and metabolism through the modulation of protein and lipid synthesis, lysosome biogenesis, and autophagy. The activity of mTORC1 is dynamically regulated by several environmental cues, including amino acid availability, growth factors, energy levels, and stresses, to coordinate cellular status with environmental conditions. Dysregulation of mTORC1 activity is closely associated with various diseases, including diabetes, cancer, and neurodegenerative disorders. The discovery of Rag GTPases has greatly expanded our understanding of the regulation of mTORC1 activity by amino acids, especially leucine and arginine. In addition to Rag GTPases, other factors that also contribute to the modulation of mTORC1 activity have been identified. In this review, we discuss the mechanisms of regulation of mTORC1 activity by particular amino acids.
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Affiliation(s)
- Terunao Takahara
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.
| | - Yuna Amemiya
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Risa Sugiyama
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Hideki Shibata
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
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89
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Tafur L, Kefauver J, Loewith R. Structural Insights into TOR Signaling. Genes (Basel) 2020; 11:E885. [PMID: 32759652 PMCID: PMC7464330 DOI: 10.3390/genes11080885] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 12/31/2022] Open
Abstract
The Target of Rapamycin (TOR) is a highly conserved serine/threonine protein kinase that performs essential roles in the control of cellular growth and metabolism. TOR acts in two distinct multiprotein complexes, TORC1 and TORC2 (mTORC1 and mTORC2 in humans), which maintain different aspects of cellular homeostasis and orchestrate the cellular responses to diverse environmental challenges. Interest in understanding TOR signaling is further motivated by observations that link aberrant TOR signaling to a variety of diseases, ranging from epilepsy to cancer. In the last few years, driven in large part by recent advances in cryo-electron microscopy, there has been an explosion of available structures of (m)TORC1 and its regulators, as well as several (m)TORC2 structures, derived from both yeast and mammals. In this review, we highlight and summarize the main findings from these reports and discuss both the fascinating and unexpected molecular biology revealed and how this knowledge will potentially contribute to new therapeutic strategies to manipulate signaling through these clinically relevant pathways.
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Affiliation(s)
- Lucas Tafur
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
| | - Jennifer Kefauver
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, 30 quai Ernest-Ansermet, CH1211 Geneva, Switzerland; (L.T.); (J.K.)
- Swiss National Centre for Competence in Research (NCCR) in Chemical Biology, University of Geneva, Sciences II, Room 3-308, 30 Quai Ernest-Ansermet, CH1211 Geneva, Switzerland
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90
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Green R, Sonal, Wang L, Hart SFM, Lu W, Skelding D, Burton JC, Mi H, Capel A, Chen HA, Lin A, Subramaniam AR, Rabinowitz JD, Shou W. Metabolic excretion associated with nutrient-growth dysregulation promotes the rapid evolution of an overt metabolic defect. PLoS Biol 2020; 18:e3000757. [PMID: 32833957 PMCID: PMC7470746 DOI: 10.1371/journal.pbio.3000757] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 09/03/2020] [Accepted: 07/20/2020] [Indexed: 01/19/2023] Open
Abstract
In eukaryotes, conserved mechanisms ensure that cell growth is coordinated with nutrient availability. Overactive growth during nutrient limitation ("nutrient-growth dysregulation") can lead to rapid cell death. Here, we demonstrate that cells can adapt to nutrient-growth dysregulation by evolving major metabolic defects. Specifically, when yeast lysine-auxotrophic mutant lys- encountered lysine limitation, an evolutionarily novel stress, cells suffered nutrient-growth dysregulation. A subpopulation repeatedly evolved to lose the ability to synthesize organosulfurs (lys-orgS-). Organosulfurs, mainly reduced glutathione (GSH) and GSH conjugates, were released by lys- cells during lysine limitation when growth was dysregulated, but not during glucose limitation when growth was regulated. Limiting organosulfurs conferred a frequency-dependent fitness advantage to lys-orgS- by eliciting a proper slow growth program, including autophagy. Thus, nutrient-growth dysregulation is associated with rapid organosulfur release, which enables the selection of organosulfur auxotrophy to better tune cell growth to the metabolic environment. We speculate that evolutionarily novel stresses can trigger atypical release of certain metabolites, setting the stage for the evolution of new ecological interactions.
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Affiliation(s)
- Robin Green
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Sonal
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Lin Wang
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Samuel F. M. Hart
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Wenyun Lu
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - David Skelding
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Justin C. Burton
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Hanbing Mi
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Aric Capel
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Hung Alex Chen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Aaron Lin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Arvind R. Subramaniam
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Joshua D. Rabinowitz
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Wenying Shou
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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91
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N-myristoyltransferase-1 is necessary for lysosomal degradation and mTORC1 activation in cancer cells. Sci Rep 2020; 10:11952. [PMID: 32686708 PMCID: PMC7371688 DOI: 10.1038/s41598-020-68615-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 06/25/2020] [Indexed: 12/31/2022] Open
Abstract
N-myristoyltransferase-1 (NMT1) catalyzes protein myristoylation, a lipid modification that is elevated in cancer cells. NMT1 sustains proliferation and/or survival of cancer cells through mechanisms that are not completely understood. We used genetic and pharmacological inhibition of NMT1 to further dissect the role of this enzyme in cancer, and found an unexpected essential role for NMT1 at promoting lysosomal metabolic functions. Lysosomes mediate enzymatic degradation of vesicle cargo, and also serve as functional platforms for mTORC1 activation. We show that NMT1 is required for both lysosomal functions in cancer cells. Inhibition of NMT1 impaired lysosomal degradation leading to autophagy flux blockade, and simultaneously caused the dissociation of mTOR from the surface of lysosomes leading to decreased mTORC1 activation. The regulation of lysosomal metabolic functions by NMT1 was largely mediated through the lysosomal adaptor LAMTOR1. Accordingly, genetic targeting of LAMTOR1 recapitulated most of the lysosomal defects of targeting NMT1, including defective lysosomal degradation. Pharmacological inhibition of NMT1 reduced tumor growth, and tumors from treated animals had increased apoptosis and displayed markers of lysosomal dysfunction. Our findings suggest that compounds targeting NMT1 may have therapeutic benefit in cancer by preventing mTORC1 activation and simultaneously blocking lysosomal degradation, leading to cancer cell death.
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92
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Shin HR, Zoncu R. The Lysosome at the Intersection of Cellular Growth and Destruction. Dev Cell 2020; 54:226-238. [PMID: 32610045 DOI: 10.1016/j.devcel.2020.06.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/01/2020] [Indexed: 12/27/2022]
Abstract
The lysosome is an essential catabolic organelle that consumes cellular biomass to regenerate basic building blocks that can fuel anabolic reactions. This simple view has evolved more recently to integrate novel functions of the lysosome as a key signaling center, which can steer the metabolic trajectory of cells in response to changes in nutrients, growth factors, and stress. Master protein kinases and transcription factors mediate the growth-promoting and catabolic activities of the lysosome and undergo a complex interplay that enables cellular adaptation to ever-changing metabolic conditions. Understanding how this coordination occurs will shed light on the fundamental logic of how the lysosome functions to control growth in the context of development, tissue homeostasis, and cancer.
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Affiliation(s)
- Hijai R Shin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California Berkeley, Berkeley, CA 94720, USA.
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93
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Laribee RN, Weisman R. Nuclear Functions of TOR: Impact on Transcription and the Epigenome. Genes (Basel) 2020; 11:E641. [PMID: 32532005 PMCID: PMC7349558 DOI: 10.3390/genes11060641] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/04/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
The target of rapamycin (TOR) protein kinase is at the core of growth factor- and nutrient-dependent signaling pathways that are well-known for their regulation of metabolism, growth, and proliferation. However, TOR is also involved in the regulation of gene expression, genomic and epigenomic stability. TOR affects nuclear functions indirectly through its activity in the cytoplasm, but also directly through active nuclear TOR pools. The mechanisms by which TOR regulates its nuclear functions are less well-understood compared with its cytoplasmic activities. TOR is an important pharmacological target for several diseases, including cancer, metabolic and neurological disorders. Thus, studies of the nuclear functions of TOR are important for our understanding of basic biological processes, as well as for clinical implications.
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Affiliation(s)
- R. Nicholas Laribee
- Department of Pathology and Laboratory Medicine, College of Medicine and Center for Cancer Research, University of Tennessee Health Science Center, 19 South Manassas, Cancer Research Building Rm 318, Memphis, TN 38163, USA
| | - Ronit Weisman
- Department of Natural and Life Sciences, The Open University of Israel, University Road 1, Ra’anana 4353701, Israel
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94
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Milanesi R, Coccetti P, Tripodi F. The Regulatory Role of Key Metabolites in the Control of Cell Signaling. Biomolecules 2020; 10:biom10060862. [PMID: 32516886 PMCID: PMC7356591 DOI: 10.3390/biom10060862] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
Robust biological systems are able to adapt to internal and environmental perturbations. This is ensured by a thick crosstalk between metabolism and signal transduction pathways, through which cell cycle progression, cell metabolism and growth are coordinated. Although several reports describe the control of cell signaling on metabolism (mainly through transcriptional regulation and post-translational modifications), much fewer information is available on the role of metabolism in the regulation of signal transduction. Protein-metabolite interactions (PMIs) result in the modification of the protein activity due to a conformational change associated with the binding of a small molecule. An increasing amount of evidences highlight the role of metabolites of the central metabolism in the control of the activity of key signaling proteins in different eukaryotic systems. Here we review the known PMIs between primary metabolites and proteins, through which metabolism affects signal transduction pathways controlled by the conserved kinases Snf1/AMPK, Ras/PKA and TORC1. Interestingly, PMIs influence also the mitochondrial retrograde response (RTG) and calcium signaling, clearly demonstrating that the range of this phenomenon is not limited to signaling pathways related to metabolism.
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95
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Devare MN, Kim YH, Jung J, Kang WK, Kwon K, Kim J. TORC1 signaling regulates cytoplasmic pH through Sir2 in yeast. Aging Cell 2020; 19:e13151. [PMID: 32449834 PMCID: PMC7294778 DOI: 10.1111/acel.13151] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/20/2020] [Accepted: 03/27/2020] [Indexed: 12/15/2022] Open
Abstract
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.
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Affiliation(s)
- Mayur Nimbadas Devare
- Department of Microbiology and Molecular Biology College of Bioscience and Biotechnology Chungnam National University Daejeon Korea
| | - Yeong Hyeock Kim
- Department of Microbiology and Molecular Biology College of Bioscience and Biotechnology Chungnam National University Daejeon Korea
| | - Joohye Jung
- Department of Microbiology and Molecular Biology College of Bioscience and Biotechnology Chungnam National University Daejeon Korea
| | - Woo Kyu Kang
- Department of Microbiology and Molecular Biology College of Bioscience and Biotechnology Chungnam National University Daejeon Korea
| | - Ki‐Sun Kwon
- Aging Intervention Research Center Korea Research Institute of Bioscience and Biotechnology Daejeon Korea
| | - Jeong‐Yoon Kim
- Department of Microbiology and Molecular Biology College of Bioscience and Biotechnology Chungnam National University Daejeon Korea
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96
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Zhu M, Wang XQ. Regulation of mTORC1 by Small GTPases in Response to Nutrients. J Nutr 2020; 150:1004-1011. [PMID: 31965176 DOI: 10.1093/jn/nxz301] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/07/2019] [Accepted: 11/18/2019] [Indexed: 12/15/2022] Open
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) is a highly evolutionarily conserved serine/threonine kinase that regulates cell growth and metabolism in response to multiple environmental cues, such as nutrients, hormones, energy, and stress. Deregulation of mTORC1 can lead to diseases such as diabetes, obesity, and cancer. A series of small GTPases, including Rag, Ras homolog enriched in brain (Rheb), adenosine diphosphate ribosylation factor 1 (Arf1), Ras-related protein Ral-A, Ras homolog (Rho), and Rab, are involved in regulating mTORC1 in response to nutrients, and mTORC1 is differentially regulated via these small GTPases according to specific conditions. Leucine and arginine sensing are considered to be well-confirmed amino acid-sensing signals, activating mTORC1 via a Rag GTPase-dependent mechanism as well as the Ragulator complex and vacuolar H+-adenosine triphosphatase (v-ATPase). Glutamine promotes mTORC1 activation via Arf1 independently of the Rag GTPase. In this review, we summarize current knowledge regarding the regulation of mTORC1 activity by small GTPases in response to nutrients, focusing on the function of small GTPases in mTORC1 activation and how small GTPases are regulated by nutrients.
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Affiliation(s)
- Min Zhu
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong, China
| | - Xiu-Qi Wang
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong, China
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97
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Rodríguez-López M, Gonzalez S, Hillson O, Tunnacliffe E, Codlin S, Tallada VA, Bähler J, Rallis C. The GATA Transcription Factor Gaf1 Represses tRNAs, Inhibits Growth, and Extends Chronological Lifespan Downstream of Fission Yeast TORC1. Cell Rep 2020; 30:3240-3249.e4. [PMID: 32160533 PMCID: PMC7068653 DOI: 10.1016/j.celrep.2020.02.058] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 12/17/2019] [Accepted: 02/13/2020] [Indexed: 12/13/2022] Open
Abstract
Target of Rapamycin Complex 1 (TORC1) signaling promotes growth and aging. Inhibition of TORC1 leads to reduced protein translation, which promotes longevity. TORC1-dependent post-transcriptional regulation of protein translation has been well studied, while analogous transcriptional regulation is less understood. Here we screen fission yeast mutants for resistance to Torin1, which inhibits TORC1 and cell growth. Cells lacking the GATA factor Gaf1 (gaf1Δ) grow normally even in high doses of Torin1. The gaf1Δ mutation shortens the chronological lifespan of non-dividing cells and diminishes Torin1-mediated longevity. Expression profiling and genome-wide binding experiments show that upon TORC1 inhibition, Gaf1 directly upregulates genes for small-molecule metabolic pathways and indirectly represses genes for protein translation. Surprisingly, Gaf1 binds to and downregulates the tRNA genes, so it also functions as a transcription factor for RNA polymerase III. Thus, Gaf1 controls the transcription of both protein-coding and tRNA genes to inhibit translation and growth downstream of TORC1.
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Affiliation(s)
- María Rodríguez-López
- Institute of Healthy Ageing and Department of Genetics, Evolution & Environment, University College London, London WC1E 6BT, UK
| | - Suam Gonzalez
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, London E14 4LZ, UK
| | - Olivia Hillson
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, London E14 4LZ, UK
| | - Edward Tunnacliffe
- Institute of Healthy Ageing and Department of Genetics, Evolution & Environment, University College London, London WC1E 6BT, UK
| | - Sandra Codlin
- Institute of Healthy Ageing and Department of Genetics, Evolution & Environment, University College London, London WC1E 6BT, UK
| | - Victor A Tallada
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC, 41013 Sevilla, Spain
| | - Jürg Bähler
- Institute of Healthy Ageing and Department of Genetics, Evolution & Environment, University College London, London WC1E 6BT, UK.
| | - Charalampos Rallis
- Institute of Healthy Ageing and Department of Genetics, Evolution & Environment, University College London, London WC1E 6BT, UK; School of Health, Sport and Bioscience, University of East London, Stratford Campus, London E14 4LZ, UK; School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.
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98
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González A, Hall MN, Lin SC, Hardie DG. AMPK and TOR: The Yin and Yang of Cellular Nutrient Sensing and Growth Control. Cell Metab 2020; 31:472-492. [PMID: 32130880 DOI: 10.1016/j.cmet.2020.01.015] [Citation(s) in RCA: 495] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The AMPK (AMP-activated protein kinase) and TOR (target-of-rapamycin) pathways are interlinked, opposing signaling pathways involved in sensing availability of nutrients and energy and regulation of cell growth. AMPK (Yin, or the "dark side") is switched on by lack of energy or nutrients and inhibits cell growth, while TOR (Yang, or the "bright side") is switched on by nutrient availability and promotes cell growth. Genes encoding the AMPK and TOR complexes are found in almost all eukaryotes, suggesting that these pathways arose very early during eukaryotic evolution. During the development of multicellularity, an additional tier of cell-extrinsic growth control arose that is mediated by growth factors, but these often act by modulating nutrient uptake so that AMPK and TOR remain the underlying regulators of cellular growth control. In this review, we discuss the evolution, structure, and regulation of the AMPK and TOR pathways and the complex mechanisms by which they interact.
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Affiliation(s)
- Asier González
- Biozentrum, University of Basel, CH4056 Basel, Switzerland
| | - Michael N Hall
- Biozentrum, University of Basel, CH4056 Basel, Switzerland
| | - Sheng-Cai Lin
- School of Life Sciences, Xiamen University, Xiamen, 361102 Fujian, China
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK.
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99
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Chang FS, Wang Y, Dmitriev P, Gross J, Galione A, Pears C. A two-pore channel protein required for regulating mTORC1 activity on starvation. BMC Biol 2020; 18:8. [PMID: 31969153 PMCID: PMC6977259 DOI: 10.1186/s12915-019-0735-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/20/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Two-pore channels (TPCs) release Ca2+ from acidic intracellular stores and are implicated in a number of diseases, but their role in development is unclear. The social amoeba Dictyostelium discoideum proliferates as single cells that aggregate to form a multicellular organism on starvation. Starvation is sensed by the mTORC1 complex which, like TPC proteins, is found on acidic vesicles. Here, we address the role of TPCs in development and under starvation. RESULTS We report that disruption of the gene encoding the single Dictyostelium TPC protein, TPC2, leads to a delay in early development and prolonged growth in culture with delayed expression of early developmental genes, although a rapid starvation-induced increase in autophagy is still apparent. Ca2+ signals induced by extracellular cAMP are delayed in developing tpc2- cells, and aggregation shows increased sensitivity to weak bases, consistent with reduced acidity of the vesicles. In mammalian cells, the mTORC1 protein kinase has been proposed to suppress TPC channel opening. Here, we show a reciprocal effect as tpc2- cells show an increased level of phosphorylation of an mTORC1 substrate, 4E-BP1. mTORC1 inhibition reverses the prolonged growth and increases the efficiency of aggregation of tpc2- cells. CONCLUSION TPC2 is required for efficient growth development transition in Dictyostelium and acts through modulation of mTORC1 activity revealing a novel mode of regulation.
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Affiliation(s)
- Fu-Sheng Chang
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Yuntao Wang
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Phillip Dmitriev
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Julian Gross
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Catherine Pears
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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100
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Mechanisms of Autophagy in Metabolic Stress Response. J Mol Biol 2020; 432:28-52. [DOI: 10.1016/j.jmb.2019.09.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 01/17/2023]
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