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Yao W, Chen Y, Zhang Y, Zhong S, Ye M, Chen Y, Fan S, Ye M, Yang H, Li Y, Wu C, Fan M, Feng S, He Z, Zhou L, Zhang L, Wang Y, Liu W, Tong J, Feng D, Yi C. Ca2+-triggered Atg11-Bmh1/2-Snf1 complex assembly initiates autophagy upon glucose starvation. J Cell Biol 2024; 223:e202310049. [PMID: 38980288 PMCID: PMC11232891 DOI: 10.1083/jcb.202310049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 04/17/2024] [Accepted: 05/23/2024] [Indexed: 07/10/2024] Open
Abstract
Autophagy is essential for maintaining glucose homeostasis. However, the mechanism by which cells sense and respond to glucose starvation to induce autophagy remains incomplete. Here, we show that calcium serves as a fundamental triggering signal that connects environmental sensing to the formation of the autophagy initiation complex during glucose starvation. Mechanistically, glucose starvation instigates the release of vacuolar calcium into the cytoplasm, thus triggering the activation of Rck2 kinase. In turn, Rck2-mediated Atg11 phosphorylation enhances Atg11 interactions with Bmh1/2 bound to the Snf1-Sip1-Snf4 complex, leading to recruitment of vacuolar membrane-localized Snf1 to the PAS and subsequent Atg1 activation, thereby initiating autophagy. We also identified Glc7, a protein phosphatase-1, as a critical regulator of the association between Bmh1/2 and the Snf1 complex. We thus propose that calcium-triggered Atg11-Bmh1/2-Snf1 complex assembly initiates autophagy by controlling Snf1-mediated Atg1 activation in response to glucose starvation.
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Affiliation(s)
- Weijing Yao
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yingcong Chen
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Zhang
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Shu Zhong
- School of Life Sciences, Central China Normal University, Wuhan, China
| | - Miaojuan Ye
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Yuting Chen
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyu Fan
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Miao Ye
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Huan Yang
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yixing Li
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Choufei Wu
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Mingzhu Fan
- Mass Spectrometry & Metabolomics Core Facility, Key Laboratory of Structural Biology of Zhejiang Province, Westlake University, Hangzhou, China
| | - Shan Feng
- Mass Spectrometry & Metabolomics Core Facility, Key Laboratory of Structural Biology of Zhejiang Province, Westlake University, Hangzhou, China
| | - Zhaoxiang He
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Long Zhou
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liqin Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou University, Huzhou, China
| | - Yigang Wang
- Xinyuan Institute of Medicine and Biotechnology, School of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Wei Liu
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jingjing Tong
- School of Life Sciences, Central China Normal University, Wuhan, China
| | - Du Feng
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Cong Yi
- Department of Biochemistry and Department of Hepatobiliary and Pancreatic Surgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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2
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Obsilova V, Obsil T. The yeast 14-3-3 proteins Bmh1 and Bmh2 regulate key signaling pathways. Front Mol Biosci 2024; 11:1327014. [PMID: 38328397 PMCID: PMC10847541 DOI: 10.3389/fmolb.2024.1327014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/15/2024] [Indexed: 02/09/2024] Open
Abstract
Cell signaling regulates several physiological processes by receiving, processing, and transmitting signals between the extracellular and intracellular environments. In signal transduction, phosphorylation is a crucial effector as the most common posttranslational modification. Selectively recognizing specific phosphorylated motifs of target proteins and modulating their functions through binding interactions, the yeast 14-3-3 proteins Bmh1 and Bmh2 are involved in catabolite repression, carbon metabolism, endocytosis, and mitochondrial retrograde signaling, among other key cellular processes. These conserved scaffolding molecules also mediate crosstalk between ubiquitination and phosphorylation, the spatiotemporal control of meiosis, and the activity of ion transporters Trk1 and Nha1. In humans, deregulation of analogous processes triggers the development of serious diseases, such as diabetes, cancer, viral infections, microbial conditions and neuronal and age-related diseases. Accordingly, the aim of this review article is to provide a brief overview of the latest findings on the functions of yeast 14-3-3 proteins, focusing on their role in modulating the aforementioned processes.
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Affiliation(s)
- Veronika Obsilova
- Institute of Physiology of the Czech Academy of Sciences, Laboratory of Structural Biology of Signaling Proteins, Division, BIOCEV, Vestec, Czechia
| | - Tomas Obsil
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czechia
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3
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González B, Mirzaei M, Basu S, Pujari AN, Vandermeulen MD, Prabhakar A, Cullen PJ. Turnover and bypass of p21-activated kinase during Cdc42-dependent MAPK signaling in yeast. J Biol Chem 2023; 299:105297. [PMID: 37774975 PMCID: PMC10641623 DOI: 10.1016/j.jbc.2023.105297] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 10/01/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathways regulate multiple cellular behaviors, including the response to stress and cell differentiation, and are highly conserved across eukaryotes. MAPK pathways can be activated by the interaction between the small GTPase Cdc42p and the p21-activated kinase (Ste20p in yeast). By studying MAPK pathway regulation in yeast, we recently found that the active conformation of Cdc42p is regulated by turnover, which impacts the activity of the pathway that regulates filamentous growth (fMAPK). Here, we show that Ste20p is regulated in a similar manner and is turned over by the 26S proteasome. This turnover did not occur when Ste20p was bound to Cdc42p, which presumably stabilized the protein to sustain MAPK pathway signaling. Although Ste20p is a major component of the fMAPK pathway, genetic approaches here identified a Ste20p-independent branch of signaling. Ste20p-independent signaling partially required the fMAPK pathway scaffold and Cdc42p-interacting protein, Bem4p, while Ste20p-dependent signaling required the 14-3-3 proteins, Bmh1p and Bmh2p. Interestingly, Ste20p-independent signaling was inhibited by one of the GTPase-activating proteins for Cdc42p, Rga1p, which unexpectedly dampened basal but not active fMAPK pathway activity. These new regulatory features of the Rho GTPase and p21-activated kinase module may extend to related pathways in other systems.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Mahnoosh Mirzaei
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Sukanya Basu
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Atindra N Pujari
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Matthew D Vandermeulen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Aditi Prabhakar
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Paul J Cullen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, USA.
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Zhang R, Feng W, Qian S, Li S, Wang F. Regulation of Rim4 distribution, function, and stability during meiosis by PKA, Cdc14, and 14-3-3 proteins. Cell Rep 2023; 42:113052. [PMID: 37659077 PMCID: PMC10591911 DOI: 10.1016/j.celrep.2023.113052] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 09/04/2023] Open
Abstract
Meiotic gene expression in budding yeast is tightly controlled by RNA-binding proteins (RBPs), with the meiosis-specific RBP Rim4 playing a key role in sequestering mid-late meiotic transcripts to prevent premature translation. However, the mechanisms governing assembly and disassembly of the Rim4-mRNA complex, critical for Rim4's function and stability, remain poorly understood. In this study, we unveil regulation of the Rim4 ribonucleoprotein (RNP) complex by the yeast 14-3-3 proteins Bmh1 and Bmh2. These proteins form a Rim4-Bmh1-Bmh2 heterotrimeric complex that expels mRNAs from Rim4 binding. We identify four Bmh1/2 binding sites (BBSs) on Rim4, with two residing within the RNA recognition motifs (RRMs). Phosphorylation and dephosphorylation of serine/threonine (S/T) residues at these BBSs by PKA kinase and Cdc14 phosphatase activities primarily control formation of Rim4-Bmh1/2, regulating Rim4's subcellular distribution, function, and stability. These findings shed light on the intricate post-transcriptional regulatory mechanisms governing meiotic gene expression.
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Affiliation(s)
- Rudian Zhang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wenzhi Feng
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Suhong Qian
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shunjin Li
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Fei Wang
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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5
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Gonz Lez B, Mirzaei M, Basu S, Prabhakar A, Cullen PJ. New Features Surrounding the Cdc42-Ste20 Module that Regulates MAP Kinase Signaling in Yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.28.530426. [PMID: 36909494 PMCID: PMC10002611 DOI: 10.1101/2023.02.28.530426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Mitogen-activated protein kinase (MAPK) pathways regulate multiple cellular responses, including the response to stress and cell differentiation, and are highly conserved across eukaryotes from yeast to humans. In yeast, the canonical activation of several MAPK pathways includes the interaction of the small GTPase Cdc42p with the p21-activated kinase (PAK) Ste20p. We recently found that the active conformation of Cdc42p is regulated by turnover, which impacts the activity of the pathway that regulates filamentous growth (fMAPK). Here, we show that Ste20p is turned over by the 26S proteasome. Ste20p was stabilized when bound to Cdc42p, presumably to sustain MAPK pathway signaling. Ste20p is a major conduit by which signals flow through the fMAPK pathway; however, by genetic approaches we also identified a Ste20p-independent branch of the fMAPK pathway. Ste20p-dependent signaling required the 14-3-3 proteins, Bmh1p and Bmh2p, while Ste20p-independent signaling required the fMAPK pathway adaptor and Cdc42p-interacting protein, Bem4p. Ste20p-independent signaling was inhibited by one of the GTPase-activating proteins for Cdc42p in the fMAPK pathway, Rga1p, which also dampened basal but not active fMAPK pathway activity. Finally, the polarity adaptor and Cdc42p-interacting protein, Bem1p, which also regulates the fMAPK pathway, interacts with the tetra-span protein Sho1p, connecting a sensor at the plasma membrane to a protein that regulates the GTPase module. Collectively, these data reveal new regulatory features surrounding a Rho-PAK module that may extend to other pathways that control cell differentiation.
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6
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Gavade JN, Puccia CM, Herod SG, Trinidad JC, Berchowitz LE, Lacefield S. Identification of 14-3-3 proteins, Polo kinase, and RNA-binding protein Pes4 as key regulators of meiotic commitment in budding yeast. Curr Biol 2022; 32:1534-1547.e9. [PMID: 35240051 PMCID: PMC9007917 DOI: 10.1016/j.cub.2022.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/04/2022] [Accepted: 02/04/2022] [Indexed: 01/25/2023]
Abstract
The initiation of the cell division process of meiosis requires exogenous signals that activate internal gene regulatory networks. Meiotic commitment ensures the irreversible continuation of meiosis, even upon withdrawal of the meiosis-inducing signals. A loss of meiotic commitment can cause highly abnormal polyploid cells and can ultimately lead to germ cell tumors. Despite the importance of meiotic commitment, only a few genes involved in commitment are known. In this study, we have discovered six new regulators of meiotic commitment in budding yeast: the Bcy1 protein involved in nutrient sensing, the meiosis-specific kinase Ime2, Polo kinase Cdc5, RNA-binding protein Pes4, and the 14-3-3 proteins Bmh1 and Bmh2. Decreased levels of these proteins cause a failure to establish or maintain meiotic commitment. Importantly, we found that Bmh1 and Bmh2 are involved in multiple processes throughout meiosis and in meiotic commitment. First, cells depleted of both Bmh1 and Bmh2 trigger the pachytene checkpoint, likely due to a role in DNA double-strand break repair. Second, Bmh1 interacts directly with the middle meiosis transcription factor Ndt80, and both Bmh1 and Bmh2 maintain Ndt80 levels. Third, Bmh1 and Bmh2 bind to Cdc5 and enhance its kinase activity. Finally, Bmh1 binds to Pes4, which regulates the timing of the translation of several mRNAs in meiosis II and is required to maintain meiotic commitment. Our results demonstrate that meiotic commitment is actively maintained throughout meiosis, with the 14-3-3 proteins and Polo kinase serving as key regulators of this developmental program.
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Affiliation(s)
| | - Chris M Puccia
- Indiana University, Department of Biology, Bloomington, IN, USA
| | - S Grace Herod
- Columbia University Irving Medical Center, Department of Genetics and Development, Hammer Health Sciences Center, New York, NY, USA
| | | | - Luke E Berchowitz
- Columbia University Irving Medical Center, Department of Genetics and Development, Hammer Health Sciences Center, New York, NY, USA
| | - Soni Lacefield
- Indiana University, Department of Biology, Bloomington, IN, USA.
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7
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The 14-3-3 Proteins as Important Allosteric Regulators of Protein Kinases. Int J Mol Sci 2020; 21:ijms21228824. [PMID: 33233473 PMCID: PMC7700312 DOI: 10.3390/ijms21228824] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/14/2022] Open
Abstract
Phosphorylation by kinases governs many key cellular and extracellular processes, such as transcription, cell cycle progression, differentiation, secretion and apoptosis. Unsurprisingly, tight and precise kinase regulation is a prerequisite for normal cell functioning, whereas kinase dysregulation often leads to disease. Moreover, the functions of many kinases are regulated through protein–protein interactions, which in turn are mediated by phosphorylated motifs and often involve associations with the scaffolding and chaperon protein 14-3-3. Therefore, the aim of this review article is to provide an overview of the state of the art on 14-3-3-mediated kinase regulation, focusing on the most recent mechanistic insights into these important protein–protein interactions and discussing in detail both their structural aspects and functional consequences.
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8
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Verhoeven MD, Bracher JM, Nijland JG, Bouwknegt J, Daran JMG, Driessen AJM, van Maris AJA, Pronk JT. Laboratory evolution of a glucose-phosphorylation-deficient, arabinose-fermenting S. cerevisiae strain reveals mutations in GAL2 that enable glucose-insensitive l-arabinose uptake. FEMS Yeast Res 2019; 18:5026172. [PMID: 29860442 PMCID: PMC6044391 DOI: 10.1093/femsyr/foy062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
Cas9-assisted genome editing was used to construct an engineered glucose-phosphorylation-negative S. cerevisiae strain, expressing the Lactobacillus plantaruml-arabinose pathway and the Penicillium chrysogenum transporter PcAraT. This strain, which showed a growth rate of 0.26 h−1 on l-arabinose in aerobic batch cultures, was subsequently evolved for anaerobic growth on l-arabinose in the presence of d-glucose and d-xylose. In four strains isolated from two independent evolution experiments the galactose-transporter gene GAL2 had been duplicated, with all alleles encoding Gal2N376T or Gal2N376I substitutions. In one strain, a single GAL2 allele additionally encoded a Gal2T89I substitution, which was subsequently also detected in the independently evolved strain IMS0010. In 14C-sugar-transport assays, Gal2N376S, Gal2N376T and Gal2N376I substitutions showed a much lower glucose sensitivity of l-arabinose transport and a much higher Km for d-glucose transport than wild-type Gal2. Introduction of the Gal2N376I substitution in a non-evolved strain enabled growth on l-arabinose in the presence of d-glucose. Gal2N376T, T89I and Gal2T89I variants showed a lower Km for l-arabinose and a higher Km for d-glucose than wild-type Gal2, while reverting Gal2N376T, T89I to Gal2N376 in an evolved strain negatively affected anaerobic growth on l-arabinose. This study indicates that optimal conversion of mixed-sugar feedstocks may require complex ‘transporter landscapes’, consisting of sugar transporters with complementary kinetic and regulatory properties.
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Affiliation(s)
- Maarten D Verhoeven
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jasmine M Bracher
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jeroen G Nijland
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jonna Bouwknegt
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jean-Marc G Daran
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Antonius J A van Maris
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Jack T Pronk
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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9
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The 14-3-3 Protein Homolog ArtA Regulates Development and Secondary Metabolism in the Opportunistic Plant Pathogen Aspergillus flavus. Appl Environ Microbiol 2018; 84:AEM.02241-17. [PMID: 29247055 PMCID: PMC5812931 DOI: 10.1128/aem.02241-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/06/2017] [Indexed: 01/07/2023] Open
Abstract
The opportunistic plant-pathogenic fungus Aspergillus flavus produces carcinogenic mycotoxins termed aflatoxins (AF). Aflatoxin contamination of agriculturally important crops, such as maize, peanut, sorghum, and tree nuts, is responsible for serious adverse health and economic impacts worldwide. In order to identify possible genetic targets to reduce AF contamination, we have characterized the artA gene, encoding a putative 14-3-3 homolog in A. flavus The artA deletion mutant presents a slight decrease in vegetative growth and alterations in morphological development and secondary metabolism. Specifically, artA affects conidiation, and this effect is influenced by the type of substrate and culture condition. In addition, normal levels of artA are required for sclerotial development. Importantly, artA negatively regulates AF production as well as the concomitant expression of genes in the AF gene cluster. An increase in AF is also observed in seeds infected with the A. flavus strain lacking artA Furthermore, the expression of other secondary metabolite genes is also artA dependent, including genes in the cyclopiazonic acid (CPA) and ustiloxin gene clusters, in this agriculturally important fungus.IMPORTANCE In the current study, artA, which encodes a 14-3-3 homolog, was characterized in the agriculturally and medically important fungus Aspergillus flavus, specifically, its possible role governing sporulation, formation of resistant structures, and secondary metabolism. The highly conserved artA is necessary for normal fungal morphogenesis in an environment-dependent manner, affecting the balance between production of conidiophores and the formation of resistant structures that are necessary for the dissemination and survival of this opportunistic pathogen. This study reports a 14-3-3 protein affecting secondary metabolism in filamentous fungi. Importantly, artA regulates the biosynthesis of the potent carcinogenic compound aflatoxin B1 (AFB1) as well as the production of other secondary metabolites.
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10
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Kumar R. An account of fungal 14-3-3 proteins. Eur J Cell Biol 2017; 96:206-217. [PMID: 28258766 DOI: 10.1016/j.ejcb.2017.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 01/09/2023] Open
Abstract
14-3-3s are a group of relatively low molecular weight, acidic, dimeric, protein(s) conserved from single-celled yeast to multicellular vertebrates including humans. Despite lacking catalytic activity, these proteins have been shown to be involved in multiple cellular processes. Apart from their role in normal cellular physiology, recently these proteins have been implicated in various medical consequences. In this present review, fungal 14-3-3 protein localization, interactions, transcription, regulation, their role in the diverse cellular process including DNA duplication, cell cycle, protein trafficking or secretion, apoptosis, autophagy, cell viability under stress, gene expression, spindle positioning, role in carbon metabolism have been discussed. In the end, I also highlighted various roles of yeasts 14-3-3 proteins in tabular form. Thus this review with primary emphasis on yeast will help in appreciating the significance of 14-3-3 proteins in cell physiology.
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Affiliation(s)
- Ravinder Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, Maharashtra, India.
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11
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Longo V, Ždralević M, Guaragnella N, Giannattasio S, Zolla L, Timperio AM. Proteome and metabolome profiling of wild-type and YCA1-knock-out yeast cells during acetic acid-induced programmed cell death. J Proteomics 2015; 128:173-88. [PMID: 26269384 DOI: 10.1016/j.jprot.2015.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/03/2015] [Accepted: 08/05/2015] [Indexed: 01/13/2023]
Abstract
UNLABELLED Caspase proteases are responsible for the regulated disassembly of the cell into apoptotic bodies during mammalian apoptosis. Structural homologues of the caspase family (called metacaspases) are involved in programmed cell death in single-cell eukaryotes, yet the molecular mechanisms that contribute to death are currently undefined. Recent evidence revealed that a programmed cell death process is induced by acetic acid (AA-PCD) in Saccharomyces cerevisiae both in the presence and absence of metacaspase encoding gene YCA1. Here, we report an unexpected role for the yeast metacaspase in protein quality and metabolite control. By using an "omics" approach, we focused our attention on proteins and metabolites differentially modulated en route to AA-PCD either in wild type or YCA1-lacking cells. Quantitative proteomic and metabolomic analyses of wild type and Δyca1 cells identified significant alterations in carbohydrate catabolism, lipid metabolism, proteolysis and stress-response, highlighting the main roles of metacaspase in AA-PCD. Finally, deletion of YCA1 led to AA-PCD pathway through the activation of ceramides, whereas in the presence of the gene yeast cells underwent an AA-PCD pathway characterized by the shift of the main glycolytic pathway to the pentose phosphate pathway and a proteolytic mechanism to cope with oxidative stress. SIGNIFICANCE The yeast metacaspase regulates both proteolytic activities through the ubiquitin-proteasome system and ceramide metabolism as revealed by proteome and metabolome profiling of YCA1-knock-out cells during acetic-acid induced programmed cell death.
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Affiliation(s)
- Valentina Longo
- Department of Ecology and Biology, "La Tuscia" University, Viterbo, Italy
| | - Maša Ždralević
- Institute of Biomembrane and Bioenergetics, CNR, Bari, Italy
| | | | | | - Lello Zolla
- Department of Ecology and Biology, "La Tuscia" University, Viterbo, Italy.
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12
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Comparative proteomics of mitosis and meiosis in Saccharomyces cerevisiae. J Proteomics 2014; 109:1-15. [DOI: 10.1016/j.jprot.2014.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 05/21/2014] [Accepted: 06/08/2014] [Indexed: 12/18/2022]
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13
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14-3-3 interaction with histone H3 involves a dual modification pattern of phosphoacetylation. Mol Cell Biol 2008; 28:2840-9. [PMID: 18268010 DOI: 10.1128/mcb.01457-07] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Histone modifications occur in precise patterns and are proposed to signal the recruitment of effector molecules that profoundly impact chromatin structure, gene regulation, and cell cycle events. The linked modifications serine 10 phosphorylation and lysine 14 acetylation on histone H3 (H3S10phK14ac), modifications conserved from Saccharomyces cerevisiae to humans, are crucial for transcriptional activation of many genes. However, the mechanism of H3S10phK14ac involvement in these processes is unclear. To shed light on the role of this dual modification, we utilized H3 peptide affinity assays to identify H3S10phK14ac-interacting proteins. We found that the interaction of the known phospho-binding 14-3-3 proteins with H3 is dependent on the presence of both of these marks, not just phosphorylation alone. This is true of mammalian 14-3-3 proteins as well as the yeast homologues Bmh1 and Bmh2. The importance of acetylation in this interaction is also seen in vivo, where K14 acetylation is required for optimal Bmh1 recruitment to the GAL1 promoter during transcriptional activation.
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14
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Lecchi S, Nelson CJ, Allen KE, Swaney DL, Thompson KL, Coon JJ, Sussman MR, Slayman CW. Tandem phosphorylation of Ser-911 and Thr-912 at the C terminus of yeast plasma membrane H+-ATPase leads to glucose-dependent activation. J Biol Chem 2007; 282:35471-81. [PMID: 17932035 DOI: 10.1074/jbc.m706094200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In recent years there has been growing interest in the post-translational regulation of P-type ATPases by protein kinase-mediated phosphorylation. Pma1 H(+)-ATPase, which is responsible for H(+)-dependent nutrient uptake in yeast (Saccharomyces cerevisiae), is one such example, displaying a rapid 5-10-fold increase in activity when carbon-starved cells are exposed to glucose. Activation has been linked to Ser/Thr phosphorylation in the C-terminal tail of the ATPase, but the specific phosphorylation sites have not previously been mapped. The present study has used nanoflow high pressure liquid chromatography coupled with electrospray electron transfer dissociation tandem mass spectrometry to identify Ser-911 and Thr-912 as two major phosphorylation sites that are clearly related to glucose activation. In carbon-starved cells with low Pma1 activity, peptide 896-918, which was derived from the C terminus upon Lys-C proteolysis, was found to be singly phosphorylated at Thr-912, whereas in glucose-metabolizing cells with high ATPase activity, the same peptide was doubly phosphorylated at Ser-911 and Thr-912. Reciprocal (14)N/(15)N metabolic labeling of cells was used to measure the relative phosphorylation levels at the two sites. The addition of glucose to carbon-starved cells led to a 3-fold reduction in the singly phosphorylated form and an 11-fold increase in the doubly phosphorylated form. These results point to a mechanism in which the stepwise phosphorylation of two tandemly positioned residues near the C terminus mediates glucose-dependent activation of the H(+)-ATPase.
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Affiliation(s)
- Silvia Lecchi
- Department of Genetics and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06511, USA
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15
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Baker SP, Grant PA. The SAGA continues: expanding the cellular role of a transcriptional co-activator complex. Oncogene 2007; 26:5329-40. [PMID: 17694076 PMCID: PMC2746020 DOI: 10.1038/sj.onc.1210603] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Throughout the last decade, great advances have been made in our understanding of how DNA-templated cellular processes occur in the native chromatin environment. Proteins that regulate transcription, replication, DNA repair, mitosis and other processes must be targeted to specific regions of the genome and granted access to DNA, which is normally tightly packaged in the higher-order chromatin structure of eukaryotic nuclei. Massive multiprotein complexes have been discovered, which facilitate access to DNA and recruitment of downstream effectors through three distinct mechanisms: chemical modification of histone amino-acid residues, ATP-dependent chromatin remodeling and histone exchange. The yeast Spt-Ada-Gcn5-Acetyl transferase (SAGA) transcriptional co-activator complex regulates numerous cellular processes through coordination of multiple histone post-translational modifications. SAGA is known to generate and interact with a number of histone modifications, including acetylation, methylation, ubiquitylation and phosphorylation. Although best characterized for its role in regulating transcriptional activation, SAGA is also required for optimal transcription elongation, mRNA export and perhaps nucleotide excision repair. Here, we discuss findings from recent years that have elucidated the function of this 1.8-MDa complex in multiple cellular processes, and how misregulation of the homologous complexes in humans may ultimately play a role in development of disease.
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Affiliation(s)
- S P Baker
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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16
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Sun W, Yu T, Li KC. Detection of eQTL modules mediated by activity levels of transcription factors. ACTA ACUST UNITED AC 2007; 23:2290-7. [PMID: 17599927 DOI: 10.1093/bioinformatics/btm327] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
MOTIVATION Studies of gene expression quantitative trait loci (eQTL) in different organisms have shown the existence of eQTL hot spots: each being a small segment of DNA sequence that harbors the eQTL of a large number of genes. Two questions of great interest about eQTL hot spots arise: (1) which gene within the hot spot is responsible for the linkages, i.e. which gene is the quantitative trait gene (QTG)? (2) How does a QTG affect the expression levels of many genes linked to it? Answers to the first question can be offered by available biological evidence or by statistical methods. The second question is harder to address. One simple situation is that the QTG encodes a transcription factor (TF), which regulates the expression of genes linked to it. However, previous results have shown that TFs are not overrepresented in the eQTL hot spots. In this article, we consider the scenario that the propagation of genetic perturbation from a QTG to other linked genes is mediated by the TF activity. We develop a procedure to detect the eQTL modules (eQTL hot spots together with linked genes) that are compatible with this scenario. RESULTS We first detect 27 eQTL modules from a yeast eQTL data, and estimate TF activity profiles using the method of Yu and Li (2005). Then likelihood ratio tests (LRTs) are conducted to find 760 relationships supporting the scenario of TF activity mediation: (DNA polymorphism --> cis-linked gene --> TF activity --> downstream linked gene). They are organized into 4 eQTL modules: an amino acid synthesis module featuring a cis-linked gene LEU2 and the mediating TF Leu3; a pheromone response module featuring a cis-linked gene GPA1 and the mediating TF Ste12; an energy-source control module featuring two cis-linked genes, GSY2 and HAP1, and the mediating TF Hap1; a mitotic exit module featuring four cis-linked genes, AMN1, CSH1, DEM1 and TOS1, and the mediating TF complex Ace2/Swi5. Gene Ontology is utilized to reveal interesting functional groups of the downstream genes in each module. AVAILABILITY Our methods are implemented in an R package: eqtl.TF, which includes source codes and relevant data. It can be freely downloaded at http://www.stat.ucla.edu/~sunwei/software.htm. SUPPLEMENTARY INFORMATION http://www.stat.ucla.edu/~sunwei/yeast_eQTL_TF/supplementary.pdf.
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Affiliation(s)
- Wei Sun
- Department of Statistics, University of California at Los Angeles, Los Angeles, California, USA
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17
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Deletion of the cruciform binding domain in CBP/14-3-3 displays reduced origin binding and initiation of DNA replication in budding yeast. BMC Mol Biol 2007; 8:27. [PMID: 17430600 PMCID: PMC1865385 DOI: 10.1186/1471-2199-8-27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Accepted: 04/12/2007] [Indexed: 11/17/2022] Open
Abstract
Background Initiation of eukaryotic DNA replication involves many protein-protein and protein-DNA interactions. We have previously shown that 14-3-3 proteins bind cruciform DNA and associate with mammalian and yeast replication origins in a cell cycle dependent manner. Results By expressing the human 14-3-3ε, as the sole member of 14-3-3 proteins family in Saccharomyces cerevisiae, we show that 14-3-3ε complements the S. cerevisiae Bmh1/Bmh2 double knockout, conserves its cruciform binding activity, and associates in vivo with the yeast replication origins ARS307. Deletion of the α5-helix, the potential cruciform binding domain of 14-3-3, decreased the cruciform binding activity of the protein as well as its association with the yeast replication origins ARS307 and ARS1. Furthermore, the mutant cells had a reduced ability to stably maintain plasmids bearing one or multiple origins. Conclusion 14-3-3, a cruciform DNA binding protein, associates with yeast origins of replication and functions as an initiator of DNA replication, presumably through binding to cruciform DNA forming at yeast replicators.
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18
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Dial JM, Petrotchenko EV, Borchers CH. Inhibition of APCCdh1 Activity by Cdh1/Acm1/Bmh1 Ternary Complex Formation. J Biol Chem 2007; 282:5237-48. [PMID: 17178718 DOI: 10.1074/jbc.m606589200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The anaphase-promoting complex (APC) is an essential E3 ubiquitin ligase responsible for catalyzing proteolysis of key regulatory proteins in the cell cycle. Cdh1 is a co-activator of the APC aiding in the onset and maintenance of G(1) phase, whereas phosphorylation of Cdh1 at the end of G(1) phase by cyclin-dependent kinases assists in the inactivation of APC(Cdh1). Here, we suggest additional components are involved in the inactivation of APC(Cdh1) independent of Cdh1 phosphorylation. We have identified proteins known as Acm1 and Bmh1, which bind and form a ternary complex with Cdh1. The presence of phosphorylated Acm1 is critical for the ternary complex formation, and Acm1 is predominantly expressed in S phase when APC(Cdh1) is inactive. The assembly of the ternary complex inhibits ubiquitination of Clb2 in vitro by blocking the interaction of Cdh1 with Clb2. In vivo, lethality caused by overexpression of constitutively active Cdh1 is rescued by overexpression of Acm1. Partially phosphorylated Cdh1 in the absence of ACM1 still binds to and activates the APC. However, the addition of Acm1 decreases Clb2 ubiquitination when using either phosphorylated or nonphosphorylated Cdh1. Taken together, our results suggest an additional inactivation mechanism exists for APC(Cdh1) that is independent of Cdh1 phosphorylation.
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Affiliation(s)
- J Michael Dial
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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19
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Du Y, Masters SC, Khuri FR, Fu H. Monitoring 14-3-3 protein interactions with a homogeneous fluorescence polarization assay. ACTA ACUST UNITED AC 2006; 11:269-76. [PMID: 16699128 DOI: 10.1177/1087057105284862] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The 14-3-3 proteins mediate phosphorylation-dependent protein-protein interactions. Through binding to numerous client proteins, 14-3-3 controls a wide range of physiological processes and has been implicated in a variety of diseases, including cancer and neurodegenerative disorders. To better understand the structure and function of 14-3-3 proteins and to develop small-molecule modulators of 14-3-3 proteins for physiological studies and potential therapeutic interventions, the authors have designed and optimized a highly sensitive fluorescence polarization (FP)-based 14-3-3 assay. Using the interaction of 14-3-3 with a fluorescently labeled phosphopeptide from Raf-1 as a model system, they have achieved a simple 1-step "mix-and-measure" method for analyzing 14-3-3 proteins. This is a solution-based, versatile method that can be used to monitor the binding of 14-3-3 with a variety of client proteins. The 14-3-3 FP assay is highly stable and has achieved a robust performance in a 384-well format with a demonstrated signal-to-noise ratio greater than 10 and a Z' factor greater than 0.7. Because of its simplicity and high sensitivity, this assay is generally applicable to studying 14-3-3/client-protein interactions and especially valuable for high-throughput screening of 14-3-3 modulators.
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Affiliation(s)
- Yuhong Du
- Department of Pharmacology, Emory University School of Medicine and Emory Chemistry-Biology Discovery Center, Emory University, Atlanta, GA 30322, USA
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20
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Michelsen K, Mrowiec T, Duderstadt KE, Frey S, Minor DL, Mayer MP, Schwappach B. A Multimeric Membrane Protein Reveals 14-3-3 Isoform Specificity in Forward Transport in Yeast. Traffic 2006; 7:903-16. [PMID: 16734667 DOI: 10.1111/j.1600-0854.2006.00430.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Arginine (Arg)-based endoplasmic reticulum (ER) localization signals are sorting motifs involved in the quality control of multimeric membrane proteins. They are distinct from other ER localization signals like the C-terminal di-lysine [-K(X)KXX] signal. The Pmp2p isoproteolipid, a type I yeast membrane protein, reports faithfully on the activity of sorting signals when fused to a tail containing either an Arg-based motif or a -KKXX signal. This reporter reveals that the Arg-based ER localization signals from mammalian Kir6.2 and GB1 proteins are functional in yeast. Thus, the machinery involved in recognition of Arg-based signals is evolutionarily conserved. Multimeric presentation of the Arg-based signal from Kir6.2 on Pmp2p results in forward transport, which requires 14-3-3 proteins encoded in yeast by BMH1 and BMH2 in two isoforms. Comparison of a strain without any 14-3-3 proteins (Deltabmh2) and the individual Deltabmh1 or Deltabmh2 shows that the role of 14-3-3 in the trafficking of this multimeric Pmp2p reporter is isoform-specific. Efficient forward transport requires the presence of Bmh1p. The specific role of Bmh1p is not due to differences in abundance or affinity between the isoforms. Our results imply that 14-3-3 proteins mediate forward transport by a mechanism distinct from simple masking of the Arg-based signal.
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Affiliation(s)
- Kai Michelsen
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
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21
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Abstract
14-3-3 proteins form a family of highly conserved proteins which are present in all eukaryotic organisms investigated, often in multiple isoforms, up to 13 in some plants. They interact with more than 200 different, mostly phosphorylated proteins. The molecular consequences of 14-3-3 binding are diverse: this binding may result in stabilization of the active or inactive phosphorylated form of the protein, to a conformational alteration leading to activation or inhibition, to a different subcellular localization, to the interaction with other proteins or to shielding of binding sites. The binding partners, and hence the 14-3-3 proteins, are involved in almost every cellular process and 14-3-3 proteins have been linked to several diseases, such as cancer, Alzheimer's disease, the neurological Miller-Dieker and spinocerebellar ataxia type 1 diseases and bovine spongiform encephalopathy (BSE). The yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe both have two genes encoding 14-3-3 proteins, BMH1 and BMH2 and rad24 and rad25, respectively. In these yeasts, 14-3-3 proteins are essential in most laboratory strains. As in higher eukaryotes, yeast 14-3-3 proteins bind to numerous proteins involved in a variety of cellular processes. Recent genome-wide studies on yeast strains with impaired 14-3-3 function support the participation of 14-3-3 proteins in numerous yeast cellular processes. Given the high evolutionary conservation of the 14-3-3 proteins, the experimental accessibility and relative simplicity of yeasts make them excellent model organisms for elucidating the function of the 14-3-3 protein family.
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Affiliation(s)
- G Paul H van Heusden
- Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
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22
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Abstract
Eukaryotic cells possess an exquisitely interwoven and fine-tuned series of signal transduction mechanisms with which to sense and respond to the ubiquitous fermentable carbon source glucose. The budding yeast Saccharomyces cerevisiae has proven to be a fertile model system with which to identify glucose signaling factors, determine the relevant functional and physical interrelationships, and characterize the corresponding metabolic, transcriptomic, and proteomic readouts. The early events in glucose signaling appear to require both extracellular sensing by transmembrane proteins and intracellular sensing by G proteins. Intermediate steps involve cAMP-dependent stimulation of protein kinase A (PKA) as well as one or more redundant PKA-independent pathways. The final steps are mediated by a relatively small collection of transcriptional regulators that collaborate closely to maximize the cellular rates of energy generation and growth. Understanding the nuclear events in this process may necessitate the further elaboration of a new model for eukaryotic gene regulation, called "reverse recruitment." An essential feature of this idea is that fine-structure mapping of nuclear architecture will be required to understand the reception of regulatory signals that emanate from the plasma membrane and cytoplasm. Completion of this task should result in a much improved understanding of eukaryotic growth, differentiation, and carcinogenesis.
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Affiliation(s)
- George M Santangelo
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS 39406-5018, USA.
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23
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Giannattasio S, Liu Z, Thornton J, Butow RA. Retrograde response to mitochondrial dysfunction is separable from TOR1/2 regulation of retrograde gene expression. J Biol Chem 2005; 280:42528-35. [PMID: 16253991 DOI: 10.1074/jbc.m509187200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retrograde (RTG) signaling senses mitochondrial dysfunction and initiates readjustments of carbohydrate and nitrogen metabolism through nuclear accumulation of the heterodimeric transcription factors, Rtg1/3p. The RTG pathway is also linked to target of rapamycin (TOR) signaling, among whose activities is transcriptional control of nitrogen catabolite repression (NCR)-sensitive genes. To investigate the connections between these two signaling pathways, we have analyzed rapamycin sensitivity of the expression of the RTG target gene CIT2 and of two NCR-sensitive genes, GLN1 and DAL5, in respiratory-competent (rho+) and -incompetent (rho0) yeast cells. Here we have presented evidence that retrograde gene expression is separable from TOR regulation of RTG- and NCR-responsive genes. We showed that expression of these two classes of genes is differentially regulated by glutamate starvation whether in response to mitochondrial dysfunction or induced by rapamycin treatment, as well by glutamine or histidine starvation. We also showed that Lst8p, a component of the TOR1/2 complexes and a negative regulator of the RTG pathway, has multiple roles in the regulation of RTG- and NCR-sensitive genes. Lst8p negatively regulates CIT2 and GLN1 expression, whereas DAL5 expression is independent of Lst8p function. DAL5 expression depends on the GATA transcription factors Gln3p and Gat1p. Gat1p is translocated to the nucleus only upon TOR inhibition by rapamycin. Altogether, these data show that Rtg1/3p, Gln3p, and Gat1p can be differentially regulated through different nutrient-sensing pathways, such as TOR and retrograde signaling, and by multiple factors, such as Lst8p, which is suggested to have a role in connecting the RTG and TOR pathways.
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Affiliation(s)
- Sergio Giannattasio
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9148, USA
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24
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Tomás-Cobos L, Viana R, Sanz P. TOR kinase pathway and 14-3-3 proteins regulate glucose-induced expression of HXT1, a yeast low-affinity glucose transporter. Yeast 2005; 22:471-9. [PMID: 15849787 DOI: 10.1002/yea.1224] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Expression of HXT1, a gene encoding a Saccharomyces cerevisiae low-affinity glucose transporter, is regulated by glucose availability, being activated in the presence of glucose and inhibited when the levels of the sugar are scarce. In this study we show that 14-3-3 proteins are involved in the regulation of the expression of HXT1 by glucose. We also demonstrate that 14-3-3 proteins, in complex with Reg1, a regulatory subunit of Glc7 protein phosphatase, interact physically with Grr1 (a component of the SCF-Grr1 ubiquitination complex), a key player in the process of HXT1 induction by glucose. In addition, we show that the TOR kinase pathway participates actively in the induction of HXT1 expression by glucose. Inhibition of the TOR kinase pathway by rapamycin treatment abolishes HXT1 glucose induction. A possible involvement of PP2A protein phosphatase complex, through the Cdc55 B-subunit, in the glucose induction of HXT1 is also discussed.
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Affiliation(s)
- Lidia Tomás-Cobos
- Instituto de Biomedicina de Valencia (CSIC), Jaime Roig 11, 46010-Valencia, Spain
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25
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Bruckmann A, Steensma H, Teixeira de Mattos M, van Heusden G. Regulation of transcription by Saccharomyces cerevisiae 14-3-3 proteins. Biochem J 2005; 382:867-75. [PMID: 15142031 PMCID: PMC1133962 DOI: 10.1042/bj20031885] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Revised: 04/28/2004] [Accepted: 05/14/2004] [Indexed: 12/22/2022]
Abstract
14-3-3 proteins form a family of highly conserved eukaryotic proteins involved in a wide variety of cellular processes, including signalling, apoptosis, cell-cycle control and transcriptional regulation. More than 150 binding partners have been found for these proteins. The yeast Saccharomyces cerevisiae has two genes encoding 14-3-3 proteins, BMH1 and BMH2. A bmh1 bmh2 double mutant is unviable in most laboratory strains. Previously, we constructed a temperature-sensitive bmh2 mutant and showed that mutations in RTG3 and SIN4, both encoding transcriptional regulators, can suppress the temperature-sensitive phenotype of this mutant, suggesting an inhibitory role of the 14-3-3 proteins in Rtg3-dependent transcription [van Heusden and Steensma (2001) Yeast 18, 1479-1491]. In the present paper, we report a genome-wide transcription analysis of a temperature-sensitive bmh2 mutant. Steady-state mRNA levels of 60 open reading frames were increased more than 2.0-fold in the bmh2 mutant, whereas those of 78 open reading frames were decreased more than 2.0-fold. In agreement with our genetic experiments, six genes known to be regulated by Rtg3 showed elevated mRNA levels in the mutant. In addition, several genes with other cellular functions, including those involved in gluconeogenesis, ergosterol biosynthesis and stress response, had altered mRNA levels in the mutant. Our data show that the yeast 14-3-3 proteins negatively regulate Rtg3-dependent transcription, stimulate the transcription of genes involved in ergosterol metabolism and in stress response and are involved in transcription regulation of multiple other genes.
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Affiliation(s)
- Astrid Bruckmann
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
| | - H. Yde Steensma
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
- †Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - M. Joost Teixeira de Mattos
- ‡Department of Microbiology, Swammerdam Institute of Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - G. Paul H. van Heusden
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
- To whom correspondence should be addressed (email )
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26
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Inoue M, Nakamura Y, Yasuda K, Yasaka N, Hara T, Schnaufer A, Stuart K, Fukuma T. The 14-3-3 proteins of Trypanosoma brucei function in motility, cytokinesis, and cell cycle. J Biol Chem 2005; 280:14085-96. [PMID: 15653691 DOI: 10.1074/jbc.m412336200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The cDNAs for two isoforms (I and II) of the 14-3-3 proteins have been cloned and functionally characterized in Trypanosoma brucei. The amino acid sequences of isoforms I and II have 47 and 50% identity to the human tau isoform, respectively, with important conserved features including a potential amphipathic groove for the binding of phosphoserine/phosphothreonine-containing motifs and a nuclear export signal-like domain. Both isoforms are abundantly expressed at approximately equal levels (1-2 x 10(6) molecules/cell) and localized mainly in the cytoplasm. Knockdown by induction of double-stranded RNA of isoform I and/or II in both bloodstream and procyclic forms resulted first in a reduction of cell motility and then significant reduction in cell growth rates and morphological changes; the changes include aberrant numbers of organelles and abnormal shapes and sizes that mimic phenotypes produced by various cytokinesis inhibitors. Morphological and fluorescence-activated cell sorting analysis of the cell cycle suggested that isoforms I and II might play important roles in nuclear (G2-M transition) and cell (M-G1 transition) division. These findings indicate that the 14-3-3 proteins play important roles in cell motility, cytokinesis, and the cell cycle.
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Affiliation(s)
- Masahiro Inoue
- Department of Parasitology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan.
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27
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Palmer GE, Johnson KJ, Ghosh S, Sturtevant J. Mutant alleles of the essential 14-3-3 gene in Candida albicans distinguish between growth and filamentation. MICROBIOLOGY-SGM 2004; 150:1911-1924. [PMID: 15184577 DOI: 10.1099/mic.0.26910-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The opportunistic fungal pathogen Candida albicans has the ability to exploit diverse host environments and can either reside commensally or cause disease. In order to adapt to its new environment it must respond to new physical conditions, nutrient sources, and the host immune response. This requires the co-regulation of multiple signalling networks. The 14-3-3 family of proteins is highly conserved in all eukaryotic species. These proteins regulate signalling pathways involved in cell survival, the cell cycle, and differentiation, and effect their functions via interactions with phosphorylated serines/threonines. In C. albicans there is only one 14-3-3 protein, Bmh1p, and it is required for vegetative growth and optimal filamentation. In order to dissect separate functions of Bmh1p in C. albicans, site-directed nucleotide substitutions were made in the C. albicans BMH1 gene based on studies in other species. Putative temperature-sensitive, ligand-binding and dimerization mutants were constructed. In addition two mutant strains identified through random mutagenesis were analysed. All five mutant strains demonstrated varying defects in growth and filamentation. This paper begins to segregate functions of Bmh1p that are required for optimal growth and the different filamentation pathways. These mutant strains will allow the identification of 14-3-3 target interactions and correlate the individual functions of Bmh1p to cellular processes involved in pathogenesis.
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Affiliation(s)
- Glen E Palmer
- Georgetown University School of Medicine, Department of Microbiology and Immunology, 3900 Reservoir Road, Washington DC 20036, USA
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Kevin J Johnson
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Sumana Ghosh
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
| | - Joy Sturtevant
- Georgetown University School of Medicine, Department of Microbiology and Immunology, 3900 Reservoir Road, Washington DC 20036, USA
- Louisiana State University School of Medicine, Department of Microbiology, Immunology, and Parasitology, Center of Excellence in Oral and Craniofacial Biology, 1100 Florida Ave, Box F8-130 New Orleans, LA 70119, USA
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28
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Oksvold MP, Huitfeldt HS, Langdon WY. Identification of 14-3-3zeta as an EGF receptor interacting protein. FEBS Lett 2004; 569:207-10. [PMID: 15225635 DOI: 10.1016/j.febslet.2004.05.068] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 05/06/2004] [Accepted: 05/10/2004] [Indexed: 11/29/2022]
Abstract
The 14-3-3 proteins are known to interact with a number of proteins involved in the regulation of cell signaling. Here, we describe an association of 14-3-3zeta with the epidermal growth factor receptor (EGFR) that is rapidly induced by EGF. The 1028-EGFR truncated mutant which lacks the cytoplasmic tail from amino acids 1029-1186 identified the binding site for 14-3-3 to be between amino acid 1028 and the receptor carboxyl terminus. Mutational deletion of serine residues 1046, 1047, 1057 and 1142 did not inhibit EGF-induced 14-3-3 association with the receptor. Immunofluorescence microscopy indicated an EGF-induced co-localization of EGFR and HA-14-3-3zeta along the plasma membrane. Our finding adds to the growing complexity of EGF receptor signaling and indicates a role for 14-3-3 proteins in EGF receptor signaling or regulation.
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Affiliation(s)
- Morten P Oksvold
- Institute of Pathology, Rikshospitalet University Hospital, University of Oslo, N-0027 Oslo, Norway.
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29
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Dombek KM, Kacherovsky N, Young ET. The Reg1-interacting proteins, Bmh1, Bmh2, Ssb1, and Ssb2, have roles in maintaining glucose repression in Saccharomyces cerevisiae. J Biol Chem 2004; 279:39165-74. [PMID: 15220335 DOI: 10.1074/jbc.m400433200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In Saccharomyces cerevisiae, a type 1 protein phosphatase complex composed of the Glc7 catalytic subunit and the Reg1 regulatory subunit represses expression of many glucose-regulated genes. Here we show that the Reg1-interacting proteins Bmh1, Bmh2, Ssb1, and Ssb2 have roles in glucose repression. Deleting both BMH genes causes partially constitutive ADH2 expression without significantly increasing the level of Adr1 protein, the major activator of ADH2 expression. Adr1 and Bcy1, the regulatory subunit of cAMP-dependent protein kinase, are both required for this effect indicating that constitutive expression in Deltabmh1Deltabmh2 cells uses the same activation pathway that operates in Deltareg1 cells. Deletion of both BMH genes and REG1 causes a synergistic relief from repression, suggesting that Bmh proteins also act independently of Reg1 during glucose repression. A two-hybrid interaction with the Bmh proteins was mapped to amino acids 187-232, a region of Reg1 that is conserved in different classes of fungi. Deleting this region partially releases SUC2 from glucose repression. This indicates a role for the Reg1-Bmh interaction in glucose repression and also suggests a broad role for Bmh proteins in this process. An in vivo Reg1-Bmh interaction was confirmed by copurification of Bmh proteins with HA(3)-TAP-tagged Reg1. The nonconventional heat shock proteins Ssb1 and Ssb2 are also copurified with HA(3)-TAP-tagged Reg1. Deletion of both SSB genes modestly decreases repression of ADH2 expression in the presence of glucose, suggesting that Ssb proteins, perhaps through their interaction with Reg1, play a minor role in glucose repression.
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Affiliation(s)
- Kenneth M Dombek
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA.
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30
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Ichimura T, Kubota H, Goma T, Mizushima N, Ohsumi Y, Iwago M, Kakiuchi K, Shekhar HU, Shinkawa T, Taoka M, Ito T, Isobe T. Transcriptomic and Proteomic Analysis of a 14-3-3 Gene-Deficient Yeast. Biochemistry 2004; 43:6149-58. [PMID: 15147199 DOI: 10.1021/bi035421i] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BMH1 and BMH2 encode Saccharomyces cerevisiae 14-3-3 homologues whose exact functions have remained unclear. The present work compares the transcriptomic and proteomic profiles of the wild type and a BMH1/2-deficient S. cerevisiae mutant (bmhDelta) using DNA microarrays and two-dimensional polyacrylamide gel electrophoresis. It is reported here that, although the global patterns of gene and protein expression are very similar between the two types of yeast cells, a subset of genes and proteins (a total of 220 genes) is significantly induced or reduced in the absence of Bmh1/2p. These genes include approximately 60 elements that could be linked to the reported phenotypes of the bmhDelta mutant (e.g., accumulation of glycogen and hypersensitivity to environmental stress) and/or could be the potential downstream targets of interacting partners of Bmh1/2p such as Msn2p and Rtg3p. Importantly, >30% of the identified genes (71 genes) were found to be associated with carbon (C) and nitrogen (N) metabolism and transport, thereby suggesting that Bmh1/2p may play a major role in the regulation of C/N-responsive cellular processes. This study presents the first comprehensive overview of the genes and proteins that are affected by the depletion of Bmh1/2p and extends the scope of knowledge of the regulatory roles of Bmh1/2p in S. cerevisiae.
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Affiliation(s)
- Tohru Ichimura
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan.
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31
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Woyke T, Berens ME, Hoelzinger DB, Pettit GR, Winkelmann G, Pettit RK. Differential gene expression in auristatin PHE-treated Cryptococcus neoformans. Antimicrob Agents Chemother 2004; 48:561-7. [PMID: 14742210 PMCID: PMC321525 DOI: 10.1128/aac.48.2.561-567.2004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifungal pentapeptide auristatin PHE was recently shown to interfere with microtubule dynamics and nuclear and cellular division in the opportunistic pathogen Cryptococcus neoformans. To gain a broader understanding of the cellular response of C. neoformans to auristatin PHE, mRNA differential display (DD) and reverse transcriptase PCR (RT-PCR) were applied. Examination of approximately 60% of the cell transcriptome from cells treated with 1.5 times the MIC (7.89 micro M) of auristatin PHE for 90 min revealed 29 transcript expression differences between control and drug-treated populations. Differential expression of seven of the transcripts was confirmed by RT-PCR, as was drug-dependent modulation of an additional seven transcripts by RT-PCR only. Among genes found to be differentially expressed were those encoding proteins involved in transport, cell cycle regulation, signal transduction, cell stress, DNA repair, nucleotide metabolism, and capsule production. For example, RHO1 and an open reading frame (ORF) encoding a protein with 91% similarity to the Schizophyllum commune 14-3-3 protein, both involved in cell cycle regulation, were down-regulated, as was the gene encoding the multidrug efflux pump Afr1p. An ORF encoding a protein with 57% identity to the heat shock protein HSP104 in Pleurotus sajor-caju was up-regulated. Also, three transcripts of unknown function were responsive to auristatin PHE, which may eventually contribute to the elucidation of the function of their gene products. Further study of these differentially expressed genes and expression of their corresponding proteins are warranted to evaluate how they may be involved in the mechanism of action of auristatin PHE. This information may also contribute to an explanation of the selectivity of auristatin PHE for C. neoformans. This is the first report of drug action using DD in C. neoformans.
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MESH Headings
- Antifungal Agents/pharmacology
- Biological Transport, Active/drug effects
- Biological Transport, Active/genetics
- Cell Cycle/drug effects
- Cell Cycle/genetics
- Cloning, Molecular
- Cryptococcus neoformans/drug effects
- Cryptococcus neoformans/genetics
- Cryptococcus neoformans/metabolism
- Culture Media
- DNA Repair/drug effects
- DNA Repair/genetics
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- Fungal Proteins/biosynthesis
- Fungal Proteins/genetics
- Gene Expression Regulation, Fungal/drug effects
- Microbial Sensitivity Tests
- Oligopeptides/pharmacology
- Purines/biosynthesis
- RNA, Fungal/biosynthesis
- RNA, Fungal/isolation & purification
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Transcription, Genetic/drug effects
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Affiliation(s)
- Tanja Woyke
- Cancer Research Institute, Arizona State University, Tempe, Arizona 85287, USA
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32
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Shen YH, Godlewski J, Bronisz A, Zhu J, Comb MJ, Avruch J, Tzivion G. Significance of 14-3-3 self-dimerization for phosphorylation-dependent target binding. Mol Biol Cell 2003; 14:4721-33. [PMID: 14551260 PMCID: PMC266786 DOI: 10.1091/mbc.e02-12-0821] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
14-3-3 proteins via binding serine/threonine-phosphorylated proteins regulate diverse intracellular processes in all eukaryotic organisms. Here, we examine the role of 14-3-3 self-dimerization in target binding, and in the susceptibility of 14-3-3 to undergo phosphorylation. Using a phospho-specific antibody developed against a degenerated mode-1 14-3-3 binding motif (RSxpSxP), we demonstrate that most of the 14-3-3-associated proteins in COS-7 cells are phosphorylated on sites that react with this antibody. The binding of these phosphoproteins depends on 14-3-3 dimerization, inasmuch as proteins associated in vivo with a monomeric 14-3-3 form are not recognized by the phospho-specific antibody. The role of 14-3-3 dimerization in the phosphorylation-dependent target binding is further exemplified with two well-defined 14-3-3 targets, Raf and DAF-16. Raf and DAF-16 can bind both monomeric and dimeric 14-3-3; however, whereas phosphorylation of specific Raf and DAF-16 sites is required for binding to dimeric 14-3-3, binding to monomeric 14-3-3 forms is entirely independent of Raf and DAF-16 phosphorylation. We also find that dimerization diminishes 14-3-3 susceptibility to phosphorylation. These findings establish a significant role of 14-3-3 dimerization in its ability to bind targets in a phosphorylation-dependent manner and point to a mechanism in which 14-3-3 phosphorylation and dimerization counterregulate each other.
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Affiliation(s)
- Ying H Shen
- Cardiovascular Research Institute, Division of Molecular Cardiology, The Texas A&M University System Health Science Center, College of Medicine, Temple, Texas 76504, USA
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33
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Mayordomo I, Regelmann J, Horak J, Sanz P. Saccharomyces cerevisiae 14-3-3 proteins Bmh1 and Bmh2 participate in the process of catabolite inactivation of maltose permease. FEBS Lett 2003; 544:160-4. [PMID: 12782308 DOI: 10.1016/s0014-5793(03)00498-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In this study we show that Reg1, the regulatory subunit of the Reg1/Glc7 protein phosphatase (PP1) complex, interacts physically with the two yeast members of the 14-3-3 protein family, Bmh1 and Bmh2. By using different fragments of the Reg1 protein we mapped the interaction domain at the N-terminal part of the protein. We also show that Reg1 and yeast 14-3-3 proteins participate actively in the regulation of the glucose-induced degradation of maltose permease (Mal61).
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Affiliation(s)
- Isabel Mayordomo
- Instituto de Biomedicina de Valencia (CSIC), Jaime Roig 11, Spain
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34
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van Hemert MJ, Deelder AM, Molenaar C, Steensma HY, van Heusden GPH. Self-association of the spindle pole body-related intermediate filament protein Fin1p and its phosphorylation-dependent interaction with 14-3-3 proteins in yeast. J Biol Chem 2003; 278:15049-55. [PMID: 12551942 DOI: 10.1074/jbc.m212495200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Fin1 protein of the yeast Saccharomyces cerevisiae forms filaments between the spindle pole bodies of dividing cells. In the two-hybrid system it binds to 14-3-3 proteins, which are highly conserved proteins involved in many cellular processes and which are capable of binding to more than 120 different proteins. Here, we describe the interaction of the Fin1 protein with the 14-3-3 proteins Bmh1p and Bmh2p in more detail. Purified Fin1p interacts with recombinant yeast 14-3-3 proteins. This interaction is strongly reduced after dephosphorylation of Fin1p. Surface plasmon resonance analysis showed that Fin1p has a higher affinity for Bmh2p than for Bmh1p (K(D) 289 versus 585 nm). Sequences in both the central and C-terminal part of Fin1p are required for the interaction with Bmh2p in the two-hybrid system. In yeast strains lacking 14-3-3 proteins Fin1 filament formation was observed, indicating that the 14-3-3 proteins are not required for this process. Fin1 also interacts with itself in the two-hybrid system. For this interaction sequences at the C terminus, containing one of two putative coiled-coil regions, are sufficient. Fin1p-Fin1p interactions were demonstrated in vivo by fluorescent resonance energy transfer between cyan fluorescent protein-labeled Fin1p and yellow fluorescent protein-labeled Fin1p.
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Affiliation(s)
- Martijn J van Hemert
- Section Yeast Genetics, Institute of Molecular Plant Sciences, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
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35
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Hurtado CAR, Rachubinski RA. YlBMH1 encodes a 14-3-3 protein that promotes filamentous growth in the dimorphic yeast Yarrowia lipolytica. MICROBIOLOGY (READING, ENGLAND) 2002; 148:3725-3735. [PMID: 12427962 DOI: 10.1099/00221287-148-11-3725] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Most pathogenic fungi have the ability to alternate between a unicellular yeast form and different filamentous forms (hyphae and pseudohyphae). This attribute is generally regarded as an important virulence factor and has also attracted attention because of its implications in the study of eukaryotic cell differentiation. To identify genes that are involved in the regulation of these events, chemical mutagenesis of the dimorphic yeast Yarrowia lipolytica was performed and morphological mutants that were unable to form hyphal cells were isolated. Screening of a Y. lipolytica genomic DNA library for genes able to complement this defect led to the isolation of YlBMH1, a gene encoding a 14-3-3 protein and whose transcription levels are increased during the yeast-to-hypha transition. Remarkably, overexpression of YlBMH1 was able to enhance pseudohyphae formation in a strain lacking functional YlRAC1 but caused no visible effects in deltamhy1 and deltabem1 cells, thus suggesting that YlBMH1 is involved in the regulation of both hyphal and pseudohyphal growth in Y. lipolytica. The identification of YlBMH2, a gene encoding a second 14-3-3 protein (YlBmh2p) that contains a 19 aa insertion absent in all other members of the 14-3-3 family, is also reported. Differently from YlBMH1, the transcription levels of YlBMH2 do not show any apparent variation during the induction of hyphal growth, and its overexpression has no effects on cells lacking functional MHY1, YlRAC1 or YlBEM1. Taken together, these observations suggest that, in spite of their high conservation, YlBmh1p and YlBmh2p have different cellular functions.
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Affiliation(s)
- Cleofe A R Hurtado
- Department of Cell Biology, University of Alberta, Medical Sciences Building 5-14, Edmonton, Alberta T6G 2H7, Canada1
| | - Richard A Rachubinski
- Department of Cell Biology, University of Alberta, Medical Sciences Building 5-14, Edmonton, Alberta T6G 2H7, Canada1
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36
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Callejo M, Alvarez D, Price GB, Zannis-Hadjopoulos M. The 14-3-3 protein homologues from Saccharomyces cerevisiae, Bmh1p and Bmh2p, have cruciform DNA-binding activity and associate in vivo with ARS307. J Biol Chem 2002; 277:38416-23. [PMID: 12167636 DOI: 10.1074/jbc.m202050200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously shown that, in human cells, cruciform DNA-binding activity is due to 14-3-3 proteins (Todd, A., Cossons, N., Aitken, A., Price, G. B., and Zannis-Hadjopoulos, M. (1998) Biochemistry 37, 14317-14325). Here, wild-type and single- and double-knockout nuclear extracts from the 14-3-3 Saccharomyces cerevisiae homologues Bmh1p and Bmh2p were analyzed for similar cruciform-binding activities in relation to these proteins. The Bmh1p-Bmh2p heterodimer, present in the wild-type strain, bound efficiently to cruciform-containing DNA in a structure-specific manner because cruciform DNA efficiently competed with the formation of the complex, whereas linear DNA did not. In contrast, the band-shift ability of the Bmh1p-Bmh1p and Bmh2p-Bmh2p homodimers present in the bmh2(-) and bmh1(-) single-knockout cells, respectively, was reduced by approximately 93 and 82%, respectively. The 14-3-3 plant homologue GF14 was also able to bind to cruciform DNA, suggesting that cruciform-binding activity is a common feature of the family of 14-3-3 proteins across species. Bmh1p and Bmh2p were found to associate in vivo with the yeast autonomous replication sequence ARS307, as assayed by formaldehyde cross-linking, followed by immunoprecipitation with anti-Bmh1p/Bmh2p antibody and conventional PCR. In agreement with the finding of an association of Bmh1p and Bmh2p with ARS307, another immunoprecipitation experiment using 2D3, an anti-cruciform DNA monoclonal antibody, revealed the presence of cruciform-containing DNA in ARS307.
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Affiliation(s)
- Mario Callejo
- Department of Biochemistry and the McGill Cancer Center, McGill University, Montreal, Quebec H3G 1Y6, Canada
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37
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Gelperin D, Horton L, DeChant A, Hensold J, Lemmon SK. Loss of ypk1 function causes rapamycin sensitivity, inhibition of translation initiation and synthetic lethality in 14-3-3-deficient yeast. Genetics 2002; 161:1453-64. [PMID: 12196392 PMCID: PMC1462197 DOI: 10.1093/genetics/161.4.1453] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
14-3-3 proteins bind to phosphorylated proteins and regulate a variety of cellular activities as effectors of serine/threonine phosphorylation. To define processes requiring 14-3-3 function in yeast, mutants with increased sensitivity to reduced 14-3-3 protein levels were identified by synthetic lethal screening. One mutation was found to be allelic to YPK1, which encodes a Ser/Thr protein kinase. Loss of Ypk function causes hypersensitivity to rapamycin, similar to 14-3-3 mutations and other mutations affecting the TOR signaling pathway in yeast. Similar to treatment with rapamycin, loss of Ypk function disrupted translation, at least in part by causing depletion of eIF4G, a central adaptor protein required for cap-dependent mRNA translation initiation. In addition, Ypk1 as well as eIF4G protein levels were rapidly depleted upon nitrogen starvation, but not during glucose starvation, even though both conditions inhibit translation initiation. These results suggest that Ypk regulates translation initiation in response to nutrient signals, either through the TOR pathway or in a functionally related pathway parallel to TOR.
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Affiliation(s)
- Daniel Gelperin
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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38
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Mayordomo I, Sanz P. The Saccharomyces cerevisiae 14-3-3 protein Bmh2 is required for regulation of the phosphorylation status of Fin1, a novel intermediate filament protein. Biochem J 2002; 365:51-6. [PMID: 11931638 PMCID: PMC1222645 DOI: 10.1042/bj20020053] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2002] [Revised: 03/20/2002] [Accepted: 04/02/2002] [Indexed: 01/25/2023]
Abstract
In order to identify proteins that interact with Bmh2, a yeast member of the 14-3-3 protein family, we performed a two-hybrid screening using LexA-Bmh2 as bait. We identified Fin1, a novel intermediate filament protein, as the protein that showed the highest degree of interaction. We also identified components of the vesicular transport machinery such as Gic2 and Msb3, proteins involved in transcriptional regulation such as Mbf1, Gcr2 and Reg2, and a variety of other different proteins (Ppt1, Lre1, Rps0A and Ylr177w). We studied the interaction between Bmh2 and Fin1 in more detail and found that Bmh2 only interacted with phosphorylated forms of Fin1. In addition, we showed that Glc7, the catalytic subunit of the protein phosphatase 1 complex, was also able to interact with Fin1.
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Affiliation(s)
- Isabel Mayordomo
- Instituto de Biomedicina de Valencia (CSIC), Jaime Roig 11, 46010-Valencia, Spain
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39
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Vasara T, Keränen S, Penttilä M, Saloheimo M. Characterisation of two 14-3-3 genes from Trichoderma reesei: interactions with yeast secretory pathway components. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1590:27-40. [PMID: 12063166 DOI: 10.1016/s0167-4889(02)00197-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The 14-3-3 proteins are highly conserved, ubiquitously expressed proteins taking part in numerous cellular processes. Two genes encoding 14-3-3 proteins, ftt1 and ftt2, were isolated and characterised from the filamentous fungus Trichoderma reesei. FTTI showed the highest sequence identity (98% at the amino acid level) to the Trichoderma harzianum protein Th1433. FTTII is relatively distinct from FTTI, showing approximately 75% identity to other fungal 14-3-3 proteins. Despite their sequence divergence, both of the T. reesei ftt genes were equally able to complement the yeast bmh1 bmh2 double disruption. The T. reesei ftt genes were also found to be quite closely linked in the genomic DNA. A C-terminally truncated version of ftt1 (ftt1DeltaC) was first isolated as a multicopy suppressor of the growth defect of the temperature-sensitive yeast secretory mutant sec15-1. Overexpression of ftt1DeltaC also suppressed the growth defect of sec2-41, sec3-101, and sec7-1 strains. Overexpression of ftt1DeltaC in sec2-41 and sec15-1 strains could also rescue the secretion of invertase at the restrictive temperatures, and overexpression of full-length ftt1 enhanced invertase secretion by wild-type yeast cells. These findings strongly suggest that the T. reesei ftt1 has a role in protein secretion.
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Affiliation(s)
- Tuija Vasara
- VTT Biotechnology, P.O. Box 1500, Tietotie 2, FIN-02044 VTT, Espoo, Finland
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40
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van Hemert MJ, Lamers GEM, Klein DCG, Oosterkamp TH, Steensma HY, van Heusden GPH. The Saccharomyces cerevisiae Fin1 protein forms cell cycle-specific filaments between spindle pole bodies. Proc Natl Acad Sci U S A 2002; 99:5390-3. [PMID: 11929974 PMCID: PMC122779 DOI: 10.1073/pnas.072556099] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The FIN1 gene from the yeast Saccharomyces cerevisiae encodes a basic protein with putative coiled-coil regions. Here we show that in large-budded cells a green fluorescent protein-Fin1 fusion protein is visible as a filament between the two spindle pole bodies. In resting cells the protein is undetectable, and in small-budded cells it is localized in the nucleus. During late mitosis it localizes on the spindle pole bodies. Filaments of cyano fluorescent protein-tagged Fin1 colocalize with filaments of green fluorescent protein-tagged Tub1 only in large-budded cells. By electron and atomic force microscopy we showed that purified recombinant Fin1p self-assembles into filaments with a diameter of approximately 10 nm. Our results indicate that the Fin1 protein forms a cell cycle-specific filament, additional to the microtubules, between the spindle pole bodies of dividing yeast cells.
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Affiliation(s)
- Martijn J van Hemert
- Section Yeast Genetics, Institute of Molecular Plant Sciences, Leiden University, Wassenaarseweg 64, 2333AL, Leiden, The Netherlands
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41
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Tzivion G, Avruch J. 14-3-3 proteins: active cofactors in cellular regulation by serine/threonine phosphorylation. J Biol Chem 2002; 277:3061-4. [PMID: 11709560 DOI: 10.1074/jbc.r100059200] [Citation(s) in RCA: 383] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Guri Tzivion
- Cardiovascular Research Institute, Division of Molecular Cardiology, Texas A&M University System Health Science Center, College of Medicine, Temple, Texas 76504, USA
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42
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Cognetti D, Davis D, Sturtevant J. The Candida albicans 14-3-3 gene, BMH1, is essential for growth. Yeast 2002; 19:55-67. [PMID: 11754483 DOI: 10.1002/yea.804] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 14-3-3 proteins are a family of conserved small acidic proteins that have been implicated in playing major roles in a wide variety of signalling cascades. In Saccharomyces cerevisiae, the 14-3-3 genes (BMH1 and BMH2) are essential for normal pseudohyphal induction and normal bud cell development. The Bmh proteins function in the cAMP-dependent RAS/MAPK and rapamycin-sensitive signalling cascades. Deletion of only one BMH gene demonstrates no phenotypic differences under normal growth conditions. Strains deleted of both BMH1 and BMH2 are either non-viable or demonstrate sensitivity to environmental stresses. In Schizosaccharomyces pombe, the BMH homologues (RAD24 and RAD25) are essential for cell cycle control after DNA damage and deletion of both genes renders the cell inviable. The 14-3-3 gene in Candida albicans (BMH1) was identified using a novel adherence assay and differential display RT-PCR. Unlike other yeasts, C. albicans has only one 14-3-3 gene (BMH1). It was not possible to construct double knockouts by routine methods. These results suggested that the C. albicans BMH1 gene is essential. The essentiality of C. albicans BMH1 was confirmed by a PCR disruption technique. The C. albicans bmh1 Delta/BMH1 heterozygotes exhibit growth and morphogenetic defects. Therefore, the BMH1 gene in C. albicans (Accession No. AF038154) is an excellent candidate to improve our understanding of the coordinate regulation of cell cycle and morphogenesis.
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Affiliation(s)
- David Cognetti
- Department of Microbiology and Immunology, Georgetown University Medical School, Washington, DC 20007, USA
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43
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Current awareness on yeast. Yeast 2001. [PMID: 11746606 DOI: 10.1002/yea.691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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44
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van Hemert MJ, Steensma HY, van Heusden GP. 14-3-3 proteins: key regulators of cell division, signalling and apoptosis. Bioessays 2001; 23:936-46. [PMID: 11598960 DOI: 10.1002/bies.1134] [Citation(s) in RCA: 418] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The 14-3-3 proteins constitute a family of conserved proteins present in all eukaryotic organisms so far investigated. These proteins have attracted interest because they are involved in important cellular processes such as signal transduction, cell-cycle control, apoptosis, stress response and malignant transformation and because at least 100 different binding partners for the 14-3-3 proteins have been reported. Although the exact function of 14-3-3 proteins is still unknown, they are known to (1) act as adaptor molecules stimulating protein-protein interactions, (2) regulate the subcellular localisation of proteins and (3) activate or inhibit enzymes. In this review, we discuss the role of the 14-3-3 proteins in three cellular processes: cell cycle control, signal transduction and apoptosis. These processes are regulated by the 14-3-3 proteins at multiple steps. The 14-3-3 proteins have an overall inhibitory effect on cell cycle progression and apoptosis, whereas in signal transduction they may act as stimulatory or inhibitory factors. This article contains supplementary material which may be viewed at the BioEssays website at http://www.interscience.wiley.com/jpages/0265-9247/Suppmat/23/v23_10.936.
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Affiliation(s)
- M J van Hemert
- Section Yeast Genetics, Institute of Molecular Plant Sciences, Leiden University, The Netherlands
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