1
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Ros-Carrero C, Spiridon-Bodi M, Igual JC, Gomar-Alba M. The CDK Pho85 inhibits Whi7 Start repressor to promote cell cycle entry in budding yeast. EMBO Rep 2024; 25:745-769. [PMID: 38233717 PMCID: PMC10897450 DOI: 10.1038/s44319-023-00049-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 01/19/2024] Open
Abstract
Pho85 is a multifunctional CDK that signals to the cell when environmental conditions are favorable. It has been connected to cell cycle control, mainly in Start where it promotes the G1/S transition. Here we describe that the Start repressor Whi7 is a key target of Pho85 in the regulation of cell cycle entry. The phosphorylation of Whi7 by Pho85 inhibits the repressor and explains most of the contribution of the CDK in the activation of Start. Mechanistically, Pho85 downregulates Whi7 protein levels through the control of Whi7 protein stability and WHI7 gene transcription. Whi7 phosphorylation by Pho85 also restrains the intrinsic ability of Whi7 to associate with promoters. Furthermore, although Whi5 is the main Start repressor in normal cycling cells, in the absence of Pho85, Whi7 becomes the major repressor leading to G1 arrest. Overall, our results reveal a novel mechanism by which Pho85 promotes Start through the regulation of the Whi7 repressor at multiple levels, which may confer to Whi7 a functional specialization to connect the response to adverse conditions with the cell cycle control.
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Affiliation(s)
- Cristina Ros-Carrero
- Institut de Biotecnologia i Biomedicina (BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100, Burjassot, Spain
| | - Mihai Spiridon-Bodi
- Institut de Biotecnologia i Biomedicina (BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100, Burjassot, Spain
| | - J Carlos Igual
- Institut de Biotecnologia i Biomedicina (BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100, Burjassot, Spain.
| | - Mercè Gomar-Alba
- Institut de Biotecnologia i Biomedicina (BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100, Burjassot, Spain.
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2
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Zhong W, He J, Huang W, Yin G, Liu G, Cao Y, Miao J. Effect of the phosphorylation structure in casein phosphopeptides on the proliferation, differentiation, and mineralization of osteoblasts and its mechanism. Food Funct 2023; 14:10107-10118. [PMID: 37874279 DOI: 10.1039/d3fo03125j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Our previous studies have shown that highly phosphorylated casein phosphopeptides (residues 1-25) P5 could efficiently bind calcium and promote intestinal calcium absorption, and enhanced bone development in rats. The purpose of this study was to investigate the effect of the phosphorylation structure in P5 on the proliferation, differentiation, and mineralization of osteoblasts (MC3T3-E1) and its mechanism. P5 was obtained by high-performance liquid chromatography (HPLC) and non-phosphorylated peptide P5-0 was obtained by chemical synthesis. Compared with the control group, the proliferation rate of MC3T3-E1 cells treated by P5 was 1.10 times that of P5-0 at 200 μg mL-1. P5 caused the cell cycle retention of MC3T3-E1 cells in the G2/M phase, while P5-0 had no significant difference in the G2/M phase. MC3T3-E1 cells incubated with P5 showed stronger alkaline phosphatase (ALP) activity than with P5-0, suggesting a tendency to promote cellular differentiation. Compared to the P5-0 treatment group, the P5 treatment group at concentrations of 10 μg mL-1 showed significant differences in the mineralization rates (p < 0.05). P5 significantly upregulated the expressions of Runx2, ALP, ColIα1, and OCN compared with the control group (p < 0.05). In addition, in silico molecular docking showed that the binding force of the P5-EGFR complex was stronger than that of the P5-0-EGFR complex, which was significantly related to the phosphorylation structure in P5 and might be an important reason for osteoblast proliferation. In conclusion, the phosphorylation structure and amino acid composition in P5 stimulated the osteogenic activity of MC3T3-E1 cells, and could be expected to be a functional food for the prevention of osteoporosis.
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Affiliation(s)
- Wanying Zhong
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Jian He
- BYHEALTH Institute of Nutrition & Health, No. 3 Kehui 3rd Street, No. 99 Kexue Avenue Central, Huangpu District, Guangzhou, Guangdong Province 510663, China
| | - Wen Huang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Guangling Yin
- BYHEALTH Institute of Nutrition & Health, No. 3 Kehui 3rd Street, No. 99 Kexue Avenue Central, Huangpu District, Guangzhou, Guangdong Province 510663, China
| | - Guo Liu
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Yong Cao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Jianyin Miao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods, College of Food Science, South China Agricultural University, Guangzhou, Guangdong 510642, China.
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3
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Deprez MA, Caligaris M, Rosseels J, Hatakeyama R, Ghillebert R, Sampaio-Marques B, Mudholkar K, Eskes E, Meert E, Ungermann C, Ludovico P, Rospert S, De Virgilio C, Winderickx J. The nutrient-responsive CDK Pho85 primes the Sch9 kinase for its activation by TORC1. PLoS Genet 2023; 19:e1010641. [PMID: 36791155 PMCID: PMC9974134 DOI: 10.1371/journal.pgen.1010641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 02/28/2023] [Accepted: 01/27/2023] [Indexed: 02/16/2023] Open
Abstract
Yeast cells maintain an intricate network of nutrient signaling pathways enabling them to integrate information on the availability of different nutrients and adjust their metabolism and growth accordingly. Cells that are no longer capable of integrating this information, or that are unable to make the necessary adaptations, will cease growth and eventually die. Here, we studied the molecular basis underlying the synthetic lethality caused by loss of the protein kinase Sch9, a key player in amino acid signaling and proximal effector of the conserved growth-regulatory TORC1 complex, when combined with either loss of the cyclin-dependent kinase (CDK) Pho85 or loss of its inhibitor Pho81, which both have pivotal roles in phosphate sensing and cell cycle regulation. We demonstrate that it is specifically the CDK-cyclin pair Pho85-Pho80 or the partially redundant CDK-cyclin pairs Pho85-Pcl6/Pcl7 that become essential for growth when Sch9 is absent. Interestingly, the respective three CDK-cyclin pairs regulate the activity and distribution of the phosphatidylinositol-3 phosphate 5-kinase Fab1 on endosomes and vacuoles, where it generates phosphatidylinositol-3,5 bisphosphate that serves to recruit both TORC1 and its substrate Sch9. In addition, Pho85-Pho80 directly phosphorylates Sch9 at Ser726, and to a lesser extent at Thr723, thereby priming Sch9 for its subsequent phosphorylation and activation by TORC1. The TORC1-Sch9 signaling branch therefore integrates Pho85-mediated information at different levels. In this context, we also discovered that loss of the transcription factor Pho4 rescued the synthetic lethality caused by loss of Pho85 and Sch9, indicating that both signaling pathways also converge on Pho4, which appears to be wired to a feedback loop involving the high-affinity phosphate transporter Pho84 that fine-tunes Sch9-mediated responses.
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Affiliation(s)
- Marie-Anne Deprez
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Marco Caligaris
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Joëlle Rosseels
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Riko Hatakeyama
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Ruben Ghillebert
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Kaivalya Mudholkar
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Elja Eskes
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Els Meert
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
| | - Christian Ungermann
- Department of Biology/Chemistry & Center of Cellular Nanoanalytics (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B’s—PT Government Associate Laboratory, Braga/Guimarães, Braga, Portugal
| | - Sabine Rospert
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail: (CDV); (JW)
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, Heverlee, Belgium
- * E-mail: (CDV); (JW)
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4
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Pérez AP, Artés MH, Moreno DF, Clotet J, Aldea M. Mad3 modulates the G 1 Cdk and acts as a timer in the Start network. SCIENCE ADVANCES 2022; 8:eabm4086. [PMID: 35522754 PMCID: PMC9075807 DOI: 10.1126/sciadv.abm4086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Cells maintain their size within limits over successive generations to maximize fitness and survival. Sizer, timer, and adder behaviors have been proposed as possible alternatives to coordinate growth and cell cycle progression. Regarding budding yeast cells, a sizer mechanism is thought to rule cell cycle entry at Start. However, while many proteins controlling the size of these cells have been identified, the mechanistic framework in which they participate to achieve cell size homeostasis is not understood. We show here that intertwined APC and SCF degradation machineries with specific adaptor proteins drive cyclic accumulation of the G1 Cdk in the nucleus, reaching maximal levels at Start. The mechanism incorporates Mad3, a centromeric-signaling protein that subordinates G1 progression to the previous mitosis as a memory factor. This alternating-degradation device displays the properties of a timer and, together with the sizer device, would constitute a key determinant of cell cycle entry.
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Affiliation(s)
- Alexis P. Pérez
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain
- Department of Basic Sciences, Universitat Internacional de Catalunya, 08195 Sant Cugat del Vallès, Spain
| | - Marta H. Artés
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain
| | - David F. Moreno
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain
| | - Josep Clotet
- Department of Basic Sciences, Universitat Internacional de Catalunya, 08195 Sant Cugat del Vallès, Spain
| | - Martí Aldea
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain
- Department of Basic Sciences, Universitat Internacional de Catalunya, 08195 Sant Cugat del Vallès, Spain
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5
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Willis SD, Hanley SE, Doyle SJ, Beluch K, Strich R, Cooper KF. Cyclin C-Cdk8 Kinase Phosphorylation of Rim15 Prevents the Aberrant Activation of Stress Response Genes. Front Cell Dev Biol 2022; 10:867257. [PMID: 35433688 PMCID: PMC9008841 DOI: 10.3389/fcell.2022.867257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
Cells facing adverse environmental cues respond by inducing signal transduction pathways resulting in transcriptional reprograming. In the budding yeast Saccharomyces cerevisiae, nutrient deprivation stimulates stress response gene (SRG) transcription critical for entry into either quiescence or gametogenesis depending on the cell type. The induction of a subset of SRGs require nuclear translocation of the conserved serine-threonine kinase Rim15. However, Rim15 is also present in unstressed nuclei suggesting that additional activities are required to constrain its activity in the absence of stress. Here we show that Rim15 is directly phosphorylated by cyclin C-Cdk8, the conserved kinase module of the Mediator complex. Several results indicate that Cdk8-dependent phosphorylation prevents Rim15 activation in unstressed cells. First, Cdk8 does not control Rim15 subcellular localization and rim15∆ is epistatic to cdk8∆ with respect to SRG transcription and the execution of starvation programs required for viability. Next, Cdk8 phosphorylates a residue in the conserved PAS domain in vitro. This modification appears important as introducing a phosphomimetic at Cdk8 target residues reduces Rim15 activity. Moreover, the Rim15 phosphomimetic only compromises cell viability in stresses that induce cyclin C destruction as well as entrance into meiosis. Taken together, these findings suggest a model in which Cdk8 phosphorylation contributes to Rim15 repression whilst it cycles through the nucleus. Cyclin C destruction in response to stress inactivates Cdk8 which in turn stimulates Rim15 to maximize SRG transcription and cell survival.
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6
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Sun S, Gresham D. Cellular quiescence in budding yeast. Yeast 2021; 38:12-29. [PMID: 33350503 DOI: 10.1002/yea.3545] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022] Open
Abstract
Cellular quiescence, the temporary and reversible exit from proliferative growth, is the predominant state of all cells. However, our understanding of the biological processes and molecular mechanisms that underlie cell quiescence remains incomplete. As with the mitotic cell cycle, budding and fission yeast are preeminent model systems for studying cellular quiescence owing to their rich experimental toolboxes and the evolutionary conservation across eukaryotes of pathways and processes that control quiescence. Here, we review current knowledge of cell quiescence in budding yeast and how it pertains to cellular quiescence in other organisms, including multicellular animals. Quiescence entails large-scale remodeling of virtually every cellular process, organelle, gene expression, and metabolic state that is executed dynamically as cells undergo the initiation, maintenance, and exit from quiescence. We review these major transitions, our current understanding of their molecular bases, and highlight unresolved questions. We summarize the primary methods employed for quiescence studies in yeast and discuss their relative merits. Understanding cell quiescence has important consequences for human disease as quiescent single-celled microbes are notoriously difficult to kill and quiescent human cells play important roles in diseases such as cancer. We argue that research on cellular quiescence will be accelerated through the adoption of common criteria, and methods, for defining cell quiescence. An integrated approach to studying cell quiescence, and a focus on the behavior of individual cells, will yield new insights into the pathways and processes that underlie cell quiescence leading to a more complete understanding of the life cycle of cells. TAKE AWAY: Quiescent cells are viable cells that have reversibly exited the cell cycle Quiescence is induced in response to a variety of nutrient starvation signals Quiescence is executed dynamically through three phases: initiation, maintenance, and exit Quiescence entails large-scale remodeling of gene expression, organelles, and metabolism Single-cell approaches are required to address heterogeneity among quiescent cells.
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Affiliation(s)
- Siyu Sun
- Center for Genomics and Systems Biology, New York University, New York, New York, 10003, USA.,Department of Biology, New York University, New York, New York, 10003, USA
| | - David Gresham
- Center for Genomics and Systems Biology, New York University, New York, New York, 10003, USA.,Department of Biology, New York University, New York, New York, 10003, USA
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7
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Méndez E, Gomar-Alba M, Bañó MC, Mendoza M, Quilis I, Igual JC. The budding yeast Start repressor Whi7 differs in regulation from Whi5, emerging as a major cell cycle brake in response to stress. J Cell Sci 2020; 133:133/24/jcs251413. [PMID: 33443080 PMCID: PMC7774886 DOI: 10.1242/jcs.251413] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/09/2020] [Indexed: 11/20/2022] Open
Abstract
Start is the main decision point in the eukaryotic cell cycle at which cells commit to a new round of cell division. It involves the irreversible activation of a transcriptional programme through the inactivation of Start transcriptional repressors: the retinoblastoma family in mammals, or Whi5 and its recently identified paralogue Whi7 (also known as Srl3) in budding yeast. Here, we provide a comprehensive comparison of Whi5 and Whi7 that reveals significant qualitative differences. Indeed, the expression, subcellular localization and functionality of Whi7 and Whi5 are differentially regulated. Importantly, Whi7 shows specific properties in its association with promoters not shared by Whi5, and for the first time, we demonstrate that Whi7, and not Whi5, can be the main contributor to Start inhibition such as it occurs in the response to cell wall stress. Our results help to improve understanding of the interplay between multiple differentially regulated Start repressors in order to face specific cellular conditions. Highlighted Article: Cells can use the interplay between functionally redundant but differentially regulated cell-cycle repressors in order to confer new repression capabilities and to respond to specific cellular conditions.
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Affiliation(s)
- Ester Méndez
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot (Valencia), Spain
| | - Mercè Gomar-Alba
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot (Valencia), Spain.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France.,Université de Strasbourg, 67000 Strasbourg, France
| | - M Carmen Bañó
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot (Valencia), Spain
| | - Manuel Mendoza
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France.,Université de Strasbourg, 67000 Strasbourg, France
| | - Inma Quilis
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot (Valencia), Spain
| | - J Carlos Igual
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED) and Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot (Valencia), Spain
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8
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Carballar R, Martínez-Láinez JM, Samper B, Bru S, Bállega E, Mirallas O, Ricco N, Clotet J, Jiménez J. CDK-mediated Yku80 Phosphorylation Regulates the Balance Between Non-homologous End Joining (NHEJ) and Homologous Directed Recombination (HDR). J Mol Biol 2020; 432:166715. [PMID: 33217428 DOI: 10.1016/j.jmb.2020.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/04/2020] [Accepted: 11/11/2020] [Indexed: 11/28/2022]
Abstract
There are two major pathways for repairing DNA double-strand breaks (DSBs): homologous directed recombination (HDR) and non-homologous end-joining (NHEJ). While NHEJ functions throughout the cell cycle, HDR is only possible during S/G2 phases, suggesting that there are cell cycle-specific mechanisms regulating the balance between the two repair systems. The regulation exerted by CDKs on HDR has been extensively demonstrated, and here we present evidence that the CDK Pho85, in association with the G1 cyclin Pcl1, phosphorylates Yku80 on Ser 623 to regulate NHEJ activity. Cells bearing a non-phosphorylatable version of Yku80 show increased NHEJ and reduced HDR activity. Accordingly, yku80S623A cells present diminished viability upon treatment with the DSB-producer bleomycin, specifically in the G2 phase of the cell cycle. Interestingly, the mutation of the equivalent residue in human Ku80 increases sensitivity to bleomycin in several cancer cell lines, suggesting that this mechanism is conserved in humans. Altogether, our results reveal a new mechanism whereby G1-CDKs mediate the choice between HDR and NHEJ repair pathways, putting the error prone NHEJ on a leash and enabling error free HDR in G2 when homologous sequences are available.
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Affiliation(s)
- Reyes Carballar
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Joan M Martínez-Láinez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Bàrbara Samper
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Samuel Bru
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Elisabet Bállega
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Oriol Mirallas
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Natalia Ricco
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Josep Clotet
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Javier Jiménez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
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9
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Austin S, Mayer A. Phosphate Homeostasis - A Vital Metabolic Equilibrium Maintained Through the INPHORS Signaling Pathway. Front Microbiol 2020; 11:1367. [PMID: 32765429 PMCID: PMC7381174 DOI: 10.3389/fmicb.2020.01367] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
Cells face major changes in demand for and supply of inorganic phosphate (Pi). Pi is often a limiting nutrient in the environment, particularly for plants and microorganisms. At the same time, the need for phosphate varies, establishing conflicts of goals. Cells experience strong peaks of Pi demand, e.g., during the S-phase, when DNA, a highly abundant and phosphate-rich compound, is duplicated. While cells must satisfy these Pi demands, they must safeguard themselves against an excess of Pi in the cytosol. This is necessary because Pi is a product of all nucleotide-hydrolyzing reactions. An accumulation of Pi shifts the equilibria of these reactions and reduces the free energy that they can provide to drive endergonic metabolic reactions. Thus, while Pi starvation may simply retard growth and division, an elevated cytosolic Pi concentration is potentially dangerous for cells because it might stall metabolism. Accordingly, the consequences of perturbed cellular Pi homeostasis are severe. In eukaryotes, they range from lethality in microorganisms such as yeast (Sethuraman et al., 2001; Hürlimann, 2009), severe growth retardation and dwarfism in plants (Puga et al., 2014; Liu et al., 2015; Wild et al., 2016) to neurodegeneration or renal Fanconi syndrome in humans (Legati et al., 2015; Ansermet et al., 2017). Intracellular Pi homeostasis is thus not only a fundamental topic of cell biology but also of growing interest for medicine and agriculture.
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Affiliation(s)
- Sisley Austin
- Département de Biochimie, Université de Lausanne, Lausanne, Switzerland
| | - Andreas Mayer
- Département de Biochimie, Université de Lausanne, Lausanne, Switzerland
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10
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Xu L, Wang F, Li R, Deng M, Fu M, Teng H, Yi K. OsCYCP4s coordinate phosphate starvation signaling with cell cycle progression in rice. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:1017-1033. [PMID: 31697021 DOI: 10.1111/jipb.12885] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Phosphate starvation leads to a strong reduction in shoot growth and yield in crops. The reduced shoot growth is caused by extensive gene expression reprogramming triggered by phosphate deficiency, which is not itself a direct consequence of low levels of shoot phosphorus. However, how phosphate starvation inhibits shoot growth in rice is still unclear. In this study, we determined the role of OsCYCP4s in the regulation of shoot growth in response to phosphate starvation in rice. We demonstrate that the expression levels of OsCYCP4s, except OsCYCP4;3, were induced by phosphate starvation. Overexpression of the phosphate starvation induced OsCYCP4s could compete with the other cyclins for the binding with cyclin-dependent kinases, therefore suppressing growth by reducing cell proliferation. The phosphate starvation induced growth inhibition in the loss-of-function mutants cycp4;1, cycp4;2, and cycp4;4 is partially compromised. Furthermore, the expression of some phosphate starvation inducible genes is negatively modulated by these cyclins, which indicates that these OsCYCP4s may also be involved in phosphate starvation signaling. We conclude that phosphate starvation induced OsCYCP4s might coordinate phosphate starvation signaling and cell cycle progression under phosphate starvation stress.
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Affiliation(s)
- Lei Xu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Fang Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Ruili Li
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Minjuan Deng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Meilan Fu
- The Semi-arid Agriculture Engineering & Technology Research Center of P. R. China, Shijiazhuang, 050000, China
| | - Huiying Teng
- The Semi-arid Agriculture Engineering & Technology Research Center of P. R. China, Shijiazhuang, 050000, China
| | - Keke Yi
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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11
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Moreno DF, Parisi E, Yahya G, Vaggi F, Csikász-Nagy A, Aldea M. Competition in the chaperone-client network subordinates cell-cycle entry to growth and stress. Life Sci Alliance 2019; 2:2/2/e201800277. [PMID: 30988162 PMCID: PMC6467244 DOI: 10.26508/lsa.201800277] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 12/22/2022] Open
Abstract
The precise coordination of growth and proliferation has a universal prevalence in cell homeostasis. As a prominent property, cell size is modulated by the coordination between these processes in bacterial, yeast, and mammalian cells, but the underlying molecular mechanisms are largely unknown. Here, we show that multifunctional chaperone systems play a concerted and limiting role in cell-cycle entry, specifically driving nuclear accumulation of the G1 Cdk-cyclin complex. Based on these findings, we establish and test a molecular competition model that recapitulates cell-cycle-entry dependence on growth rate. As key predictions at a single-cell level, we show that availability of the Ydj1 chaperone and nuclear accumulation of the G1 cyclin Cln3 are inversely dependent on growth rate and readily respond to changes in protein synthesis and stress conditions that alter protein folding requirements. Thus, chaperone workload would subordinate Start to the biosynthetic machinery and dynamically adjust proliferation to the growth potential of the cell.
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Affiliation(s)
- David F Moreno
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain
| | - Eva Parisi
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain
| | - Galal Yahya
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain.,Department of Microbiology and Immunology, Zagazig University, Zagazig, Egypt
| | - Federico Vaggi
- Department of Informatics, Ecole Normale Supérieure, INRIA, Sierra Team, Paris, France
| | - Attila Csikász-Nagy
- Randall Centre for Cell and Molecular Biophysics and Institute of Mathematical and Molecular Biomedicine, King's College London, London, UK .,Pázmány Péter Catholic University, Faculty of Information Technology and Bionics, Budapest, Hungary
| | - Martí Aldea
- Molecular Biology Institute of Barcelona, CSIC, Catalonia, Spain .,Department of Basic Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain
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12
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Evolutionary conservation of a core fungal phosphate homeostasis pathway coupled to development in Blastocladiella emersonii. Fungal Genet Biol 2018; 115:20-32. [PMID: 29627365 DOI: 10.1016/j.fgb.2018.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 01/08/2023]
Abstract
The model yeast Saccharomyces cerevisiae elicits a transcriptional response to phosphate (Pi) depletion. To determine the origins of the phosphate response (PHO) system, we bioinformatically identified putative PHO components in the predicted proteomes of diverse fungi. Our results suggest that the PHO system is ancient; however, components have been expanded or lost in different fungal lineages. To show that a similar physiological response is present in deeply-diverging fungi we examined the transcriptional and physiological response of PHO genes to Pi depletion in the blastocladiomycete Blastocladiella emersonii. Our physiological experiments indicate that B. emersonii relies solely on high-affinity Na+-independent Pho84-like transporters. In response to Pi depletion, BePho84 paralogues were 4-8-fold transcriptionally upregulated, whereas several other PHO homologues like phosphatases and vacuolar transporter chaperone (VTC) complex components show 2-3-fold transcriptional upregulation. Since Pi has been shown to be important during the development of B. emersonii, we sought to determine if PHO genes are differentially regulated at different lifecycle stages. We demonstrate that a similar set of PHO transporters and phosphatases are upregulated at key points during B. emersonii development. Surprisingly, some genes upregulated during Pi depletion, including VTC components, are repressed at these key stages of development indicating that PHO genes are regulated by different pathways in different developmental and environmental situations. Overall, our findings indicate that a complex PHO network existed in the ancient branches of the fungi, persists in diverse extant fungi, and that this ancient network is likely to be involved in development and cell cycle regulation.
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13
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Mirallas O, Ballega E, Samper-Martín B, García-Márquez S, Carballar R, Ricco N, Jiménez J, Clotet J. Intertwined control of the cell cycle and nucleocytoplasmic transport by the cyclin-dependent kinase Pho85 and RanGTPase Gsp1 in Saccharomyces cerevisiae. Microbiol Res 2017; 206:168-176. [PMID: 29146254 DOI: 10.1016/j.micres.2017.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/09/2017] [Accepted: 10/17/2017] [Indexed: 10/18/2022]
Abstract
Deciphering the molecular mechanisms that connect cell cycle progression and nucleocytoplasmic transport is of particular interest: this intertwined relationship, once understood, may provide useful insight on the diseases resulting from the malfunction of these processes. In the present study we report on findings that indicate a biochemical connection between the cell cycle regulator CDK Pho85 and Ran-GTPase Gsp1, an essential nucleocytoplasmic transport component. When Gsp1 cannot be phosphorylated by Pho85, the cell cycle progression is impaired. Accordingly, a nonphosphorylatable version of Gsp1 abnormally localizes to the nucleus, which impairs the nuclear transport of molecules, including key components of cell cycle progression. Furthermore, our results suggest that the physical interaction of Gsp1 and the Kap95 karyopherin, essential to the release of nuclear cargoes, is altered. Altogether, the present findings point to the involvement of a biochemical mechanism in the interlocked regulation of the cell cycle and nuclear transport.
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Affiliation(s)
- Oriol Mirallas
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Elisabet Ballega
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Bàrbara Samper-Martín
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Sergio García-Márquez
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Reyes Carballar
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Natalia Ricco
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Javier Jiménez
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Josep Clotet
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Barcelona, Spain.
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14
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TORC1 coordinates the conversion of Sic1 from a target to an inhibitor of cyclin-CDK-Cks1. Cell Discov 2017; 3:17012. [PMID: 28496991 PMCID: PMC5412858 DOI: 10.1038/celldisc.2017.12] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/07/2017] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cell cycle progression through G1-S is driven by hormonal and growth-related signals that are transmitted by the target of rapamycin complex 1 (TORC1) pathway. In yeast, inactivation of TORC1 restricts G1-S transition due to the rapid clearance of G1 cyclins (Cln) and the stabilization of the B-type cyclin (Clb) cyclin-dependent kinase (CDK) inhibitor Sic1. The latter mechanism remains mysterious but requires the phosphorylation of Sic1-Thr173 by Mpk1 and inactivation of the Sic1-pThr173-targeting phosphatase (PP2ACdc55) through greatwall kinase-activated endosulfines. Here we show that the Sic1-pThr173 residue serves as a specific docking site for the CDK phospho-acceptor subunit Cks1 that sequesters, together with a C-terminal Clb5-binding motif in Sic1, Clb5-CDK-Cks1 complexes, thereby preventing them from flagging Sic1 for ubiquitin-dependent proteolysis. Interestingly, this functional switch of Sic1 from a target to an inhibitor of cyclin-CDK-Cks1 also operates in proliferating cells and is coordinated by the greatwall kinase, which responds to both Cln-CDK-dependent cell-cycle and TORC1-mediated nutritional cues.
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15
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Ikeh MAC, Kastora SL, Day AM, Herrero-de-Dios CM, Tarrant E, Waldron KJ, Banks AP, Bain JM, Lydall D, Veal EA, MacCallum DM, Erwig LP, Brown AJP, Quinn J. Pho4 mediates phosphate acquisition in Candida albicans and is vital for stress resistance and metal homeostasis. Mol Biol Cell 2016; 27:2784-801. [PMID: 27385340 PMCID: PMC5007097 DOI: 10.1091/mbc.e16-05-0266] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/23/2016] [Indexed: 12/02/2022] Open
Abstract
This study provides the first evidence that the phosphate-responsive transcription factor Pho4 is vital for survival of Candida albicans to diverse and physiologically relevant stresses. Pho4 is important for C. albicans pathogenesis, and thus these findings illustrate how metabolic adaptation promotes C. albicans survival in the host. During interactions with its mammalian host, the pathogenic yeast Candida albicans is exposed to a range of stresses such as superoxide radicals and cationic fluxes. Unexpectedly, a nonbiased screen of transcription factor deletion mutants revealed that the phosphate-responsive transcription factor Pho4 is vital for the resistance of C. albicans to these diverse stresses. RNA-Seq analysis indicated that Pho4 does not induce stress-protective genes directly. Instead, we show that loss of Pho4 affects metal cation toxicity, accumulation, and bioavailability. We demonstrate that pho4Δ cells are sensitive to metal and nonmetal cations and that Pho4-mediated polyphosphate synthesis mediates manganese resistance. Significantly, we show that Pho4 is important for mediating copper bioavailability to support the activity of the copper/zinc superoxide dismutase Sod1 and that loss of Sod1 activity contributes to the superoxide sensitivity of pho4Δ cells. Consistent with the key role of fungal stress responses in countering host phagocytic defenses, we also report that C. albicans pho4Δ cells are acutely sensitive to macrophage-mediated killing and display attenuated virulence in animal infection models. The novel connections between phosphate metabolism, metal homeostasis, and superoxide stress resistance presented in this study highlight the importance of metabolic adaptation in promoting C. albicans survival in the host.
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Affiliation(s)
- Mélanie A C Ikeh
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stavroula L Kastora
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
| | - Alison M Day
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | | | - Emma Tarrant
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Kevin J Waldron
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - A Peter Banks
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Judith M Bain
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
| | - David Lydall
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Elizabeth A Veal
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Donna M MacCallum
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
| | - Lars P Erwig
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
| | - Alistair J P Brown
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom
| | - Janet Quinn
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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16
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Dilution of the cell cycle inhibitor Whi5 controls budding-yeast cell size. Nature 2015; 526:268-72. [PMID: 26390151 PMCID: PMC4600446 DOI: 10.1038/nature14908] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 07/14/2015] [Indexed: 01/04/2023]
Abstract
Cell size fundamentally affects all biosynthetic processes by determining the scale of organelles and influencing surface transport1,2. Although extensive studies have identified many mutations affecting cell size, the molecular mechanisms underlying size control have remained elusive3. In budding yeast, size control occurs in G1 phase prior to Start, the point of irreversible commitment to cell division4,5. It was previously thought that activity of the G1 cyclin Cln3 increased with cell size to trigger Start by initiating the inhibition of the transcriptional inhibitor Whi56-8. However, while Cln3 concentration does modulate the rate at which cells pass Start, we found that its synthesis increases in proportion to cell size so that its total concentration is nearly constant during pre-Start G1. Rather than increasing Cln3 activity, we identify decreasing Whi5 activity — due to the dilution of Whi5 by cell growth — as a molecular mechanism through which cell size controls proliferation. Whi5 is synthesized in S/G2/M phases of the cell cycle in a largely size-independent manner. This results in smaller daughter cells being born with higher Whi5 concentrations that extend their pre-Start G1 phase. Thus, at its most fundamental level, budding yeast size control results from the differential scaling of Cln3 and Whi5 synthesis rates with cell size. More generally, our work shows that differential size-dependency of protein synthesis can provide an elegant mechanism to coordinate cellular functions with growth.
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17
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Tsang F, Lin SJ. Less is more: Nutrient limitation induces cross-talk of nutrient sensing pathways with NAD + homeostasis and contributes to longevity. ACTA ACUST UNITED AC 2015; 10:333-357. [PMID: 27683589 DOI: 10.1007/s11515-015-1367-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nutrient sensing pathways and their regulation grant cells control over their metabolism and growth in response to changing nutrients. Factors that regulate nutrient sensing can also modulate longevity. Reduced activity of nutrient sensing pathways such as glucose-sensing PKA, nitrogen-sensing TOR and S6 kinase homolog Sch9 have been linked to increased life span in the yeast, Saccharomyces cerevisiae, and higher eukaryotes. Recently, reduced activity of amino acid sensing SPS pathway was also shown to increase yeast life span. Life span extension by reduced SPS activity requires enhanced NAD+ (nicotinamide adenine dinucleotide, oxidized form) and nicotinamide riboside (NR, a NAD+ precursor) homeostasis. Maintaining adequate NAD+ pools has been shown to play key roles in life span extension, but factors regulating NAD+ metabolism and homeostasis are not completely understood. Recently, NAD+ metabolism was also linked to the phosphate (Pi)-sensing PHO pathway in yeast. Canonical PHO activation requires Pi-starvation. Interestingly, NAD+ depletion without Pi-starvation was sufficient to induce PHO activation, increasing NR production and mobilization. Moreover, SPS signaling appears to function in parallel with PHO signaling components to regulate NR/NAD+ homeostasis. These studies suggest that NAD+ metabolism is likely controlled by and/or coordinated with multiple nutrient sensing pathways. Indeed, cross-regulation of PHO, PKA, TOR and Sch9 pathways was reported to potentially affect NAD+ metabolism; though detailed mechanisms remain unclear. This review discusses yeast longevity-related nutrient sensing pathways and possible mechanisms of life span extension, regulation of NAD+ homeostasis, and cross-talk among nutrient sensing pathways and NAD+ homeostasis.
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Affiliation(s)
- Felicia Tsang
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
| | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA
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18
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Jiménez J, Bru S, Ribeiro M, Clotet J. Live fast, die soon: cell cycle progression and lifespan in yeast cells. MICROBIAL CELL 2015; 2:62-67. [PMID: 28357278 PMCID: PMC5349179 DOI: 10.15698/mic2015.03.191] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Our understanding of lifespan has benefited enormously from the study of a simple model, the yeast Saccharomyces cerevisiae. Although a unicellular organism, yeasts undergo many of the processes directly related with aging that to some extent are conserved in mammalian cells. Nutrient-limiting conditions have been involved in lifespan extension, especially in the case of caloric restriction, which also has a direct impact on cell cycle progression. In fact, other environmental stresses (osmotic, oxidative) that interfere with normal cell cycle progression also influence the lifespan of cells, indicating a relationship between lifespan and cell cycle control. In the present review we compile and discuss new findings related to how cell cycle progression is regulated by other nutrients. We centred this review on the analysis of phosphate, also give some attention to nitrogen, and the impact of these nutrients on lifespan.
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Affiliation(s)
- Javier Jiménez
- Dept. Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut. Universitat Internacional de Catalunya, Barcelona, Catalonia, Spain
| | - Samuel Bru
- Dept. Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut. Universitat Internacional de Catalunya, Barcelona, Catalonia, Spain
| | - Mariana Ribeiro
- Dept. Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut. Universitat Internacional de Catalunya, Barcelona, Catalonia, Spain
| | - Josep Clotet
- Dept. Ciències Bàsiques, Facultat de Medicina i Ciències de la Salut. Universitat Internacional de Catalunya, Barcelona, Catalonia, Spain
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19
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Rødkær SV, Pultz D, Brusch M, Bennetzen MV, Falkenby LG, Andersen JS, Færgeman NJ. Quantitative proteomics identifies unanticipated regulators of nitrogen- and glucose starvation. MOLECULAR BIOSYSTEMS 2015; 10:2176-88. [PMID: 24909858 DOI: 10.1039/c4mb00207e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular mechanisms underlying how cells sense, respond, and adapt to alterations in nutrient availability have been studied extensively during the past years. While most of these studies have focused on the linear connections between signaling components, it is increasingly being recognized that signaling pathways are interlinked in molecular circuits and networks such that any metabolic perturbation will induce signaling-wide ripple effects. In the present study, we have used quantitative mass spectrometry (MS) to examine how the yeast Saccharomyces cerevisiae responds to nitrogen- or glucose starvation. We identify nearly 1400 phosphorylation sites of which more than 500 are regulated in a temporal manner in response to glucose- or nitrogen starvation. By bioinformatics and network analyses, we have identified the cyclin-dependent kinase (CDK) inhibitor Sic1, the Hsp90 co-chaperone Cdc37, and the Hsp90 isoform Hsp82 to putatively mediate some of the starvation responses. Consistently, quantitative expression analyses showed that Sic1, Cdc37, and Hsp82 are required for normal expression of nutrient-responsive genes. Collectively, we therefore propose that Sic1, Cdc37, and Hsp82 may orchestrate parts of the cellular starvation response by regulating transcription factor- and kinase activities.
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Affiliation(s)
- Steven V Rødkær
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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20
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Nishizawa M. The regulators of yeast PHO system participate in the transcriptional regulation of G1 cyclin under alkaline stress conditions. Yeast 2015; 32:367-78. [PMID: 25582350 DOI: 10.1002/yea.3064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 12/26/2014] [Accepted: 12/27/2014] [Indexed: 11/08/2022] Open
Abstract
The yeast Pho85 kinase oversees whether environmental conditions are favourable for cell growth and enables yeast cells to express only genes that are appropriate for the conditions. Alkaline stress perturbs transport of molecules across the plasma membrane that is vital for cell survival. Progression through the cell cycle is halted until the cells can adapt to the stress conditions. I found that Pho85 is required for CLN2 expression and that overproduction of the transcription factors Pho4, Rim101 and Crz1, all targets of Pho85, inhibited CLN2 expression. CLN2 expression in the absence of Pho85 could be recovered only when all the three transcription factors were deleted. Whi5, a functional homologue of the mammalian Rb protein, represses CLN2 expression and is inactivated when phosphorylated by either of the CDK-cyclin complexes, Cdc28-Cln3 or Pho85-Pcl9. Under alkaline conditions, the absence of Whi5 caused an increase in CLN2 expression but failed to do so when Pho85 was also absent, or when Pho4 was overproduced. The expression level of CLN2 in a Δpho85 Δpho4 Δrim101 Δcrz1 quadruple mutant was stimulated when the Whi5 activity was repressed by overproduction of Pho85-Pcl9. These results indicate that Whi5 is also under control of alkaline stress. The inhibitory function of Whi5 on CLN2 is dependent on Rpd3 HDAC, and the absence of Rpd3 could also suppress the inhibitory effect of Pho4 overproduction. Based on these findings, a model is presented in which Pho85 and Pho4 functions in CLN2 regulation under alkaline conditions.
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Affiliation(s)
- Masafumi Nishizawa
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
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21
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Liu X, Wang X, Yang X, Liu S, Jiang L, Qu Y, Hu L, Ouyang Q, Tang C. Reliable cell cycle commitment in budding yeast is ensured by signal integration. eLife 2015; 4. [PMID: 25590650 PMCID: PMC4378612 DOI: 10.7554/elife.03977] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 01/07/2015] [Indexed: 12/29/2022] Open
Abstract
Cell fate decisions are critical for life, yet little is known about how their
reliability is achieved when signals are noisy and fluctuating with time. In this
study, we show that in budding yeast, the decision of cell cycle commitment (Start)
is determined by the time integration of its triggering signal Cln3. We further
identify the Start repressor, Whi5, as the integrator. The instantaneous kinase
activity of Cln3-Cdk1 is recorded over time on the phosphorylated Whi5, and the
decision is made only when phosphorylated Whi5 reaches a threshold. Cells adjust the
threshold by modulating Whi5 concentration in different nutrient conditions to
coordinate growth and division. Our work shows that the strategy of signal
integration, which was previously found in decision-making behaviors of animals, is
adopted at the cellular level to reduce noise and minimize uncertainty. DOI:http://dx.doi.org/10.7554/eLife.03977.001 Budding yeast and other single-celled organisms can reproduce by dividing to produce
two daughter cells. The timing of the cell division is critical because if the cell
is still small when it divides, the resulting daughter cells may not be big enough to
survive. In budding yeast, the irreversible decision to divide—known as the
‘Start’ checkpoint—is only made once a cell reaches a certain
size and is triggered by a protein called Cln3. This protein controls the activity of
another protein called Whi5, which normally prevents the cell from dividing by
switching off particular genes. Cln3 adds phosphate groups to Whi5 to make
‘phosphorylated Whi5’, which allows the genes involved in cell division
to be switched on. It is commonly believed that the level of Cln3 reflects the size of the cell and the
nutrient conditions. Therefore, one model of cell division proposes that the cell
passes the Start checkpoint when the level of Cln3 reaches a threshold value.
However, levels of the Cln3 protein in cells can naturally fluctuate, and computer
simulations based on this model showed that this would not produce reliable decisions
on when to divide. So how do cells manage to distinguish noise from the genuine
signals that indicate it is the right time to divide? To address this question, Liu et al. studied yeast cells containing an artificial
version of the gene encoding the Cln3 protein whose levels could be adjusted by
adding a particular chemical. This revealed that cells with higher levels of Cln3
passed through the Start checkpoint sooner than cells that had lower levels of
Cln3. The observation suggests that cells add up the amount of Cln3 present over a period
of time to see if this reaches the threshold needed for the Start checkpoint. This
could be possible if, instead of sensing Cln3 levels directly, the cell senses the
accumulation of phosphorylated Whi5. To test this idea, Liu et al. carried out
additional experiments and found that the decision to pass the Start checkpoint only
occurs when the amount of phosphorylated Whi5 reaches a certain threshold. The cells are able to coordinate their growth and division under different nutrient
conditions by altering the threshold of phosphorylated Whi5. When the nutrient supply
is poor, more phosphorylated Whi5 needs to be accumulated to allow the cell to pass
the Start checkpoint. In this way, cells adjust when they divide according to
nutrient conditions. Similar strategies may be found in other signaling or
decision-making systems. DOI:http://dx.doi.org/10.7554/eLife.03977.002
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Affiliation(s)
- Xili Liu
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Xin Wang
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Xiaojing Yang
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Sen Liu
- Institute of Molecular Biology, College of Medical Science, China Three Gorges University, Yichang, China
| | - Lingli Jiang
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Yimiao Qu
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Lufeng Hu
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Qi Ouyang
- Center for Quantitative Biology, Peking University, Beijing, China
| | - Chao Tang
- Center for Quantitative Biology, Peking University, Beijing, China
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22
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Defects in phosphate acquisition and storage influence virulence of Cryptococcus neoformans. Infect Immun 2014; 82:2697-712. [PMID: 24711572 DOI: 10.1128/iai.01607-14] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nutrient acquisition and sensing are critical aspects of microbial pathogenesis. Previous transcriptional profiling indicated that the fungal pathogen Cryptococcus neoformans, which causes meningoencephalitis in immunocompromised individuals, encounters phosphate limitation during proliferation in phagocytic cells. We therefore tested the hypothesis that phosphate acquisition and polyphosphate metabolism are important for cryptococcal virulence. Deletion of the high-affinity uptake system interfered with growth on low-phosphate medium, perturbed the formation of virulence factors (capsule and melanin), reduced survival in macrophages, and attenuated virulence in a mouse model of cryptococcosis. Additionally, analysis of nutrient sensing functions for C. neoformans revealed regulatory connections between phosphate acquisition and storage and the iron regulator Cir1, cyclic AMP (cAMP)-dependent protein kinase A (PKA), and the calcium-calmodulin-activated protein phosphatase calcineurin. Deletion of the VTC4 gene encoding a polyphosphate polymerase blocked the ability of C. neoformans to produce polyphosphate. The vtc4 mutant behaved like the wild-type strain in interactions with macrophages and in the mouse infection model. However, the fungal load in the lungs was significantly increased in mice infected with vtc4 deletion mutants. In addition, the mutant was impaired in the ability to trigger blood coagulation in vitro, a trait associated with polyphosphate. Overall, this study reveals that phosphate uptake in C. neoformans is critical for virulence and that its regulation is integrated with key signaling pathways for nutrient sensing.
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23
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Conrad M, Schothorst J, Kankipati HN, Van Zeebroeck G, Rubio-Texeira M, Thevelein JM. Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae. FEMS Microbiol Rev 2014; 38:254-99. [PMID: 24483210 PMCID: PMC4238866 DOI: 10.1111/1574-6976.12065] [Citation(s) in RCA: 419] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/23/2013] [Accepted: 01/22/2014] [Indexed: 02/04/2023] Open
Abstract
The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth.
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Affiliation(s)
- Michaela Conrad
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Joep Schothorst
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Harish Nag Kankipati
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Griet Van Zeebroeck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Marta Rubio-Texeira
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
| | - Johan M Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU LeuvenLeuven-Heverlee, Flanders, Belgium
- Department of Molecular Microbiology, VIBLeuven-Heverlee, Flanders, Belgium
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Jiménez J, Ricco N, Grijota-Martínez C, Fadó R, Clotet J. Redundancy or specificity? The role of the CDK Pho85 in cell cycle control. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 4:140-149. [PMID: 24049669 PMCID: PMC3776146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 08/31/2013] [Indexed: 06/02/2023]
Abstract
It is generally accepted that progression through the eukaryotic cell cycle is driven by cyclin-dependent kinases (CDKs), which are regulated by interaction with oscillatory expressed proteins called cyclins. CDKs may be separated into 2 categories: essential and non-essential. Understandably, more attention has been focused on essential CDKs because they are shown to control cell cycle progression to a greater degree. After clearly determining the basic and "core" mechanisms of essential CDKs, several questions arise. What role do non-essential CDKs play? Are these CDKs functionally redundant and do they serve as a mere backup? Or might they be responsible for some accessory tasks in cell cycle progression or control? In the present review we will try to answer these questions based on recent findings on the involvement of non-essential CDKs in cell cycle progression. We will analyse the most recent information with regard to these questions in the yeast Saccharomyces cerevisiae, a well-established eukaryotic model, and in its unique non-essential CDK involved in the cell cycle, Pho85. We will also briefly extend our discussion to higher eukaryotic systems.
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Affiliation(s)
- Javier Jiménez
- Department of Basic Sciences, Faculty of Medicine and Health Sciences, International University of Catalonia Barcelona, Catalonia
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Jiménez J, Truman AW, Menoyo S, Kron SJ, Clotet J. The yin and yang of cyclin control by nutrients. Cell Cycle 2013; 12:865-6. [PMID: 23470456 PMCID: PMC3637339 DOI: 10.4161/cc.24217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Multiple Pho85-dependent mechanisms control G1 cyclin abundance in response to nutrient stress. Mol Cell Biol 2013; 33:1270-2. [PMID: 23382071 DOI: 10.1128/mcb.00086-13] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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