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Takeichi Y, Takuma T, Ohara K, Tasnin MN, Ushimaru T. Interphase chromosome condensation in nutrient-starved conditions requires Cdc14 and Hmo1, but not condensin, in yeast. Biochem Biophys Res Commun 2022; 611:46-52. [PMID: 35477092 DOI: 10.1016/j.bbrc.2022.04.078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 04/17/2022] [Indexed: 12/21/2022]
Abstract
When asynchronously growing cells suffer from nutrient depletion and inactivation of target of rapamycin complex 1 (TORC1) protein kinase, the rDNA (rRNA gene) region is condensed in budding yeast Saccharomyces cerevisiae, which is executed by condensin and Cdc14 protein phosphatase. However, it is unknown whether these mitotic factors can condense the rDNA region in nutrient-starved interphase cells. Here, we show that condensin is not involved in TORC1 inactivation-induced rDNA condensation in G1 cells. Instead, the high-mobility group protein Hmo1 drove this process. The histone deacetylase Rpd3 and Cdc14, which repress rRNA transcription, were both required for the interphase rDNA condensation. Furthermore, interphase rDNA condensation necessitated CLIP and cohibin that tether rDNA to inner nuclear membranes. Finally, we showed that Hmo1, CLIP, Rpd3, and Cdc14 were required for survival in nutrient-starved G1 cells. Thus, this study disclosed novel features of interphase chromosome condensation.
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Madeira JB, Matos GS, Messias LS, Bozaquel-Morais BL, Masuda CA, Montero-Lomeli M. Induction of triacylglycerol synthesis in yeast by cell cycle arrest. FEMS Yeast Res 2019; 19:5462652. [PMID: 30985885 DOI: 10.1093/femsyr/foz030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/13/2019] [Indexed: 12/13/2022] Open
Abstract
In this study, we found that cell cycle arrest induced by alpha-factor mating pheromone (G1), hydroxyurea (S) or nocodazole (G2/M) was associated to increased lipid droplet (LD) content. To identify novel cell cycle genes involved in LD homeostasis, we screened a deletion library for strains with altered LD levels. Among the mutants related to mitotic cell cycle, we found 24 hits that displayed a significantly higher LD content. Ontology mapping showed that neither a biological process nor a specific cell cycle phase was enriched among the hits. We decided to further study the role of SWI4 on LD homeostasis as it is involved in G1/S transition, a stage where lipolysis is active. The high LD content of swi4Δ mutant was not due to inhibition of lipolysis, but due to an increase in triacylglycerol (TAG) synthesis. In addition, deletion of the AMP kinase gene SNF1 or inhibition of TORC1 activity, both known regulators of LD homeostasis, further increased the LD content of a swi4Δ mutant. These findings highlight a role of the cell cycle regulator SWI4 in the coordination of lipid metabolism which is independent of the TORC1 and SNF1/AMPK pathways.
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Affiliation(s)
- Juliana B Madeira
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
| | - Gabriel S Matos
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
| | - Laryssa S Messias
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
| | - Bruno L Bozaquel-Morais
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
| | - Claudio A Masuda
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
| | - Monica Montero-Lomeli
- Instituto de Bioquimica Médica Leoplodo de Meis, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373, cep 21941-902, Rio de Janeiro, Rio de Janeiro Brazil
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Xi J, Cai J, Cheng Y, Fu Y, Wei W, Zhang Z, Zhuang Z, Hao Y, Lilly MA, Wei Y. The TORC1 inhibitor Nprl2 protects age-related digestive function in Drosophila. Aging (Albany NY) 2019; 11:9811-9828. [PMID: 31712450 PMCID: PMC6874466 DOI: 10.18632/aging.102428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 10/28/2019] [Indexed: 01/23/2023]
Abstract
Aging and age-related diseases occur in almost all organisms. Recently, it was discovered that the inhibition of target of rapamycin complex 1 (TORC1), a conserved complex that mediates nutrient status and cell metabolism, can extend an individual’s lifespan and inhibit age-related diseases in many model organisms. However, the mechanism whereby TORC1 affects aging remains elusive. Here, we use a loss-of-function mutation in nprl2, a component of GATOR1 that mediates amino acid levels and inhibits TORC1 activity, to investigate the effect of increased TORC1 activity on the occurrence of age-related digestive dysfunction in Drosophila. We found that the nprl2 mutation decreased Drosophila lifespan. Furthermore, the nprl2 mutant had a distended crop, with food accumulation at an early age. Interestingly, the inappropriate food distribution and digestion along with decreased crop contraction in nprl2 mutant can be rescued by decreasing TORC1 activity. In addition, nprl2-mutant flies exhibited age-related phenotypes in the midgut, including short gut length, a high rate of intestinal stem cell proliferation, and metabolic dysfunction, which could be rescued by inhibiting TORC1 activity. Our findings showed that the gastrointestinal tract aging process is accelerated in nprl2-mutant flies, owing to high TORC1 activity, which suggested that TORC1 promotes digestive tract senescence.
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Affiliation(s)
- Junmeng Xi
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.,Institute of Reproduction and Metabolism, Yangzhou University, Yangzhou, China
| | - Jiadong Cai
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.,Institute of Reproduction and Metabolism, Yangzhou University, Yangzhou, China
| | - Yang Cheng
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yuanyuan Fu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Wanhong Wei
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China
| | - Zhenbo Zhang
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ziheng Zhuang
- School of Pharmaceutical Engineering and Life Sciences, Changzhou University, Changzhou, China
| | - Yue Hao
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture, Beijing, China
| | - Mary A Lilly
- Cell Biology and Neurobiology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Youheng Wei
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China.,Institute of Reproduction and Metabolism, Yangzhou University, Yangzhou, China
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Abstract
Nutrient starvation induces the degradation of specific plasma membrane proteins through the multivesicular body (MVB) sorting pathway and of vacuolar membrane proteins through microautophagy. Both of these processes require the gateway protein Vps27, which recognizes ubiquitinated cargo proteins at phosphatidylinositol 3-phosphate-rich membranes as part of a heterodimeric complex coined endosomal sorting complex required for transport 0. The target of rapamycin complex 1 (TORC1), a nutrient-activated central regulator of cell growth, directly phosphorylates Vps27 to antagonize its function in microautophagy, but whether this also serves to restrain MVB sorting at endosomes is still an open question. Here, we show that TORC1 inhibits both the MVB pathway-driven turnover of the plasma membrane-resident high-affinity methionine permease Mup1 and the inositol transporter Itr1 and the microautophagy-dependent degradation of the vacuolar membrane-associated v-ATPase subunit Vph1. Using a Vps277D variant that mimics the TORC1-phosphorylated state of Vps27, we further show that cargo sorting of Vph1 at the vacuolar membrane, but not of Mup1 and Itr1 at endosomes, is sensitive to the TORC1-controlled modifications of Vps27. Thus, TORC1 specifically modulates microautophagy through phosphorylation of Vps27, but controls MVB sorting through alternative mechanisms.
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Affiliation(s)
- Riko Hatakeyama
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
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Suda K, Kaneko A, Shimobayashi M, Nakashima A, Maeda T, Hall MN, Ushimaru T. TORC1 regulates autophagy induction in response to proteotoxic stress in yeast and human cells. Biochem Biophys Res Commun 2019; 511:434-439. [PMID: 30797551 DOI: 10.1016/j.bbrc.2019.02.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 02/15/2019] [Indexed: 11/18/2022]
Abstract
Misfolded and aggregated proteins are eliminated to maintain protein homeostasis. Autophagy contributes to the removal of protein aggregates. However, if and how proteotoxic stress induces autophagy is poorly understood. Here we show that proteotoxic stress after treatment with azetidine-2-carboxylic acid (AZC), a toxic proline analog, induces autophagy in budding yeast. AZC treatment attenuated target of rapamycin complex 1 (TORC1) activity, resulting in the dephosphorylation of Atg13, a key factor of autophagy. By contrast, AZC treatment did not affect target of rapamycin complex 2 (TORC2). Proteotoxic stress also induced TORC1 inactivation and autophagy in fission yeast and human cells. This study suggested that TORC1 is a conserved key factor to cope with proteotoxic stress in eukaryotic cells.
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Affiliation(s)
- Kazuki Suda
- Department of Biological Science, Shizuoka University, Shizuoka, 422-8021, Japan
| | - Atsuki Kaneko
- Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, 422-8021, Japan
| | | | - Akio Nakashima
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
| | - Tatsuya Maeda
- Department of Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Michael N Hall
- Biozentrum, University of Basel, 4056, Basel, Switzerland, Switzerland
| | - Takashi Ushimaru
- Department of Biological Science, Shizuoka University, Shizuoka, 422-8021, Japan; Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, 422-8021, Japan.
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