1
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Pan L, Fonseca de Lima CF, Vu LD, van de Cotte B, De Winne N, Gevaert K, De Jaeger G, De Smet I. Heterodimerization domains in MAP4 KINASEs determine subcellular localization and activity in Arabidopsis. PLANT PHYSIOLOGY 2024; 195:1807-1817. [PMID: 38513700 DOI: 10.1093/plphys/kiae176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/31/2024] [Accepted: 02/12/2024] [Indexed: 03/23/2024]
Abstract
Signal transduction relies largely on the activity of kinases and phosphatases that control protein phosphorylation. However, we still know very little about phosphorylation-mediated signaling networks. Plant MITOGEN-ACTIVATED PROTEIN KINASE KINASE KINASE KINASEs (MAP4Ks) have recently gained more attention, given their role in a wide range of processes, including developmental processes and stress signaling. We analyzed MAP4K expression patterns and mapped protein-MAP4K interactions in Arabidopsis (Arabidopsis thaliana), revealing extensive coexpression and heterodimerization. This heterodimerization is regulated by the C-terminal, intrinsically disordered half of the MAP4K, and specifically by the coiled coil motif. The ability to heterodimerize is required for proper activity and localization of the MAP4Ks. Taken together, our results identify MAP4K-interacting proteins and emphasize the functional importance of MAP4K heterodimerization. Furthermore, we identified MAP4K4/TARGET OF TEMPERATURE3 (TOT3) and MAP4K5/TOT3-INTERACTING PROTEIN 5 (TOI5) as key regulators of the transition from cell division to elongation zones in the primary root tip.
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Affiliation(s)
- Lixia Pan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Cassio Flavio Fonseca de Lima
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Lam Dai Vu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, B-9052 Ghent, Belgium
| | - Brigitte van de Cotte
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Nancy De Winne
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, VIB, B-9052 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, B-9052 Ghent, Belgium
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium
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2
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Sang T, Chen CW, Lin Z, Ma Y, Du Y, Lin PY, Hadisurya M, Zhu JK, Lang Z, Tao WA, Hsu CC, Wang P. DIA-Based Phosphoproteomics Identifies Early Phosphorylation Events in Response to EGTA and Mannitol in Arabidopsis. Mol Cell Proteomics 2024; 23:100804. [PMID: 38901673 DOI: 10.1016/j.mcpro.2024.100804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/19/2024] [Accepted: 06/12/2024] [Indexed: 06/22/2024] Open
Abstract
Osmotic stress significantly hampers plant growth and crop yields, emphasizing the need for a thorough comprehension of the underlying molecular responses. Previous research has demonstrated that osmotic stress rapidly induces calcium influx and signaling, along with the activation of a specific subset of protein kinases, notably the Raf-like protein (RAF)-sucrose nonfermenting-1-related protein kinase 2 (SnRK2) kinase cascades within minutes. However, the intricate interplay between calcium signaling and the activation of RAF-SnRK2 kinase cascades remains elusive. Here, in this study, we discovered that Raf-like protein (RAF) kinases undergo hyperphosphorylation in response to osmotic shocks. Intriguingly, treatment with the calcium chelator EGTA robustly activates RAF-SnRK2 cascades, mirroring the effects of osmotic treatment. Utilizing high-throughput data-independent acquisition-based phosphoproteomics, we unveiled the global impact of EGTA on protein phosphorylation. Beyond the activation of RAFs and SnRK2s, EGTA treatment also activates mitogen-activated protein kinase cascades, Calcium-dependent protein kinases, and receptor-like protein kinases, etc. Through overlapping assays, we identified potential roles of mitogen-activated protein kinase kinase kinase kinases and receptor-like protein kinases in the osmotic stress-induced activation of RAF-SnRK2 cascades. Our findings illuminate the regulation of phosphorylation and cellular events by Ca2+ signaling, offering insights into the (exocellular) Ca2+ deprivation during early hyperosmolality sensing and signaling.
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Affiliation(s)
- Tian Sang
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Chin-Wen Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Zhen Lin
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yu Ma
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Yanyan Du
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Pei-Yi Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Marco Hadisurya
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Jian-Kang Zhu
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Zhaobo Lang
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - W Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA; Department of Chemistry, Purdue University, West Lafayette, Indiana, USA; Purdue Institute for Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Chuan-Chih Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
| | - Pengcheng Wang
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China.
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3
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Joshua IM, Lin M, Mardjuki A, Mazzola A, Höfken T. A Protein-Protein Interaction Analysis Suggests a Wide Range of New Functions for the p21-Activated Kinase (PAK) Ste20. Int J Mol Sci 2023; 24:15916. [PMID: 37958899 PMCID: PMC10647699 DOI: 10.3390/ijms242115916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
The p21-activated kinases (PAKs) are important signaling proteins. They contribute to a surprisingly wide range of cellular processes and play critical roles in a number of human diseases including cancer, neurological disorders and cardiac diseases. To get a better understanding of PAK functions, mechanisms and integration of various cellular activities, we screened for proteins that bind to the budding yeast PAK Ste20 as an example, using the split-ubiquitin technique. We identified 56 proteins, most of them not described previously as Ste20 interactors. The proteins fall into a small number of functional categories such as vesicle transport and translation. We analyzed the roles of Ste20 in glucose metabolism and gene expression further. Ste20 has a well-established role in the adaptation to changing environmental conditions through the stimulation of mitogen-activated protein kinase (MAPK) pathways which eventually leads to transcription factor activation. This includes filamentous growth, an adaptation to nutrient depletion. Here we show that Ste20 also induces filamentous growth through interaction with nuclear proteins such as Sac3, Ctk1 and Hmt1, key regulators of gene expression. Combining our observations and the data published by others, we suggest that Ste20 has several new and unexpected functions.
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Affiliation(s)
| | - Meng Lin
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
| | - Ariestia Mardjuki
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
| | - Alessandra Mazzola
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Department of Biopathology and Medical and Forensic Biotechnologies, University of Palermo, 90133 Palermo, Italy
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, Uxbridge UB8 3PH, UK; (I.M.J.)
- Institute of Biochemistry, Kiel University, 24118 Kiel, Germany
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4
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Vandermeulen MD, Cullen PJ. Ecological inducers of the yeast filamentous growth pathway reveal environment-dependent roles for pathway components. mSphere 2023; 8:e0028423. [PMID: 37732804 PMCID: PMC10597418 DOI: 10.1128/msphere.00284-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/31/2023] [Indexed: 09/22/2023] Open
Abstract
Signaling modules, such as mitogen-activated protein kinase (MAPK) pathways, are evolutionarily conserved drivers of cell differentiation and stress responses. In many fungal species including pathogens, MAPK pathways control filamentous growth, where cells differentiate into an elongated cell type. The convenient model budding yeast Saccharomyces cerevisiae undergoes filamentous growth by the filamentous growth (fMAPK) pathway; however, the inducers of the pathway remain unclear, perhaps because pathway activity has been mainly studied in laboratory conditions. To address this knowledge gap, an ecological framework was used, which uncovered new fMAPK pathway inducers, including pectin, a material found in plants, and the metabolic byproduct ethanol. We also show that induction by a known inducer of the pathway, the non-preferred carbon source galactose, required galactose metabolism and induced the pathway differently than glucose limitation or other non-preferred carbon sources. By exploring fMAPK pathway function in fruit, we found that induction of the pathway led to visible digestion of fruit rind through a known target, PGU1, which encodes a pectolytic enzyme. Combinations of inducers (galactose and ethanol) stimulated the pathway to near-maximal levels, which showed dispensability of several fMAPK pathway components (e.g., mucin sensor, p21-activated kinase), but not others (e.g., adaptor, MAPKKK) and required the Ras2-protein kinase A pathway. This included a difference between the transcription factor binding partners for the pathway, as Tec1p, but not Ste12p, was partly dispensable for fMAPK pathway activity. Thus, by exploring ecologically relevant stimuli, new modes of MAPK pathway signaling were uncovered, perhaps revealing how a pathway can respond differently to specific environments. IMPORTANCE Filamentous growth is a cell differentiation response and important aspect of fungal biology. In plant and animal fungal pathogens, filamentous growth contributes to virulence. One signaling pathway that regulates filamentous growth is an evolutionarily conserved MAPK pathway. The yeast Saccharomyces cerevisiae is a convenient model to study MAPK-dependent regulation of filamentous growth, although the inducers of the pathway are not clear. Here, we exposed yeast cells to ecologically relevant compounds (e.g., plant compounds), which identified new inducers of the MAPK pathway. In combination, the inducers activated the pathway to near-maximal levels but did not cause detrimental phenotypes associated with previously identified hyperactive alleles. This context allowed us to identify conditional bypass for multiple pathway components. Thus, near-maximal induction of a MAPK pathway by ecologically relevant inducers provides a powerful tool to assess cellular signaling during a fungal differentiation response.
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Affiliation(s)
| | - Paul J. Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, New York, USA
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5
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Zhu M, Liu Y, Yang X, Zhu L, Shen Y, Duan S, Yang J. p21-activated kinase is involved in the sporulation, pathogenicity, and stress response of Arthrobotrys oligospora under the indirect regulation of Rho GTPase-activating protein. Front Microbiol 2023; 14:1235283. [PMID: 37779704 PMCID: PMC10537225 DOI: 10.3389/fmicb.2023.1235283] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023] Open
Abstract
The p21-GTPase-activated protein kinases (PAKs) participate in signal transduction downstream of Rho GTPases, which are regulated by Rho GTPase-activating proteins (Rho-GAP). Herein, we characterized two orthologous Rho-GAPs (AoRga1 and AoRga2) and two PAKs (AoPak1 and AoPak2) through bioinformatics analysis and reverse genetics in Arthrobotrys oligospora, a typical nematode-trapping (NT) fungus. The transcription analyses performed at different development stages suggested that Aopaks and Aorga1 play a crucial role during sporulation and trap formation, respectively. In addition, we successfully deleted Aopak1 and Aorga1 via the homologous recombination method. The disruption of Aopak1 and Aorga1 caused a remarkable reduction in spore yield and the number of nuclei per cell, but did not affect mycelial growth. In ∆Aopak1 mutants, the trap number was decreased at 48 h after the introduction of nematodes, but nematode predatory efficiency was not affected because the extracellular proteolytic activity was increased. On the contrary, the number of traps in ∆Aorga1 mutants was significantly increased at 36 h and 48 h. In addition, Aopak1 and Aorga1 had different effects on the sensitivity to cell-wall-disturbing reagent and oxidant. A yeast two-hybrid assay revealed that AoPak1 and AoRga1 both interacted with AoRac, and AoPak1 also interacted with AoCdc42. Furthermore, the Aopaks were up-regulated in ∆Aorga1 mutants, and Aorga1 was down-regulated in ∆Aopak1 mutants. These results reveal that AoRga1 indirectly regulated AoPAKs by regulating small GTPases.
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Affiliation(s)
- Meichen Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Yankun Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Xuewei Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Lirong Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Yanmei Shen
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Shipeng Duan
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources and Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
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6
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Bardwell L, Thorner J. Mitogen-activated protein kinase (MAPK) cascades-A yeast perspective. Enzymes 2023; 54:137-170. [PMID: 37945169 DOI: 10.1016/bs.enz.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Discovery of the class of protein kinase now dubbed a mitogen (or messenger)-activated protein kinase (MAPK) is an illustrative example of how disparate lines of investigation can converge and reveal an enzyme family universally conserved among eukaryotes, from single-celled microbes to humans. Moreover, elucidation of the circuitry controlling MAPK function defined a now overarching principle in enzyme regulation-the concept of an activation cascade mediated by sequential phosphorylation events. Particularly ground-breaking for this field of exploration were the contributions of genetic approaches conducted using several model organisms, but especially the budding yeast Saccharomyces cerevisiae. Notably, examination of how haploid yeast cells respond to their secreted peptide mating pheromones was crucial in pinpointing genes encoding MAPKs and their upstream activators. Fully contemporaneous biochemical analysis of the activities elicited upon stimulation of mammalian cells by insulin and other growth- and differentiation-inducing factors lead eventually to the demonstration that components homologous to those in yeast were involved. Continued studies of these pathways in yeast were integral to other foundational discoveries in MAPK signaling, including the roles of tethering, scaffolding and docking interactions.
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Affiliation(s)
- Lee Bardwell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA, United States
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, College of Letters and Science, University of California, Berkeley, Berkeley, CA, United States.
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7
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Scott TD, Xu P, McClean MN. Strain-dependent differences in coordination of yeast signalling networks. FEBS J 2023; 290:2097-2114. [PMID: 36416575 PMCID: PMC10121740 DOI: 10.1111/febs.16689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/30/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
Abstract
The yeast mitogen-activated protein kinase pathways serve as a model system for understanding how network interactions affect the way in which cells coordinate the response to multiple signals. We have quantitatively compared two yeast strain backgrounds YPH499 and ∑1278b (both of which have previously been used to study these pathways) and found several important differences in how they coordinate the interaction between the high osmolarity glycerol (HOG) and mating pathways. In the ∑1278b background, in response to simultaneous stimulus, mating pathway activation is dampened and delayed in a dose-dependent manner. In the YPH499 background, only dampening is dose-dependent. Furthermore, leakage from the HOG pathway into the mating pathway (crosstalk) occurs during osmostress alone in the ∑1278b background only. The mitogen-activated protein kinase Hog1p suppresses crosstalk late in an induction time course in both strains but does not affect the early crosstalk seen in the ∑1278b background. Finally, the kinase Rck2p plays a greater role suppressing late crosstalk in the ∑1278b background than in the YPH499 background. Our results demonstrate that comparisons between laboratory yeast strains provide an important resource for understanding how signalling network interactions are tuned by genetic variation without significant alteration to network structure.
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Affiliation(s)
- Taylor D. Scott
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Ping Xu
- Lewis-Sigler Institute for Integrative Biology, Princeton University, Princeton, NJ, USA
| | - Megan N. McClean
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Lewis-Sigler Institute for Integrative Biology, Princeton University, Princeton, NJ, USA
- University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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8
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A focus on yeast mating: From pheromone signaling to cell-cell fusion. Semin Cell Dev Biol 2023; 133:83-95. [PMID: 35148940 DOI: 10.1016/j.semcdb.2022.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 12/14/2022]
Abstract
Cells live in a chemical environment and are able to orient towards chemical cues. Unicellular haploid fungal cells communicate by secreting pheromones to reproduce sexually. In the yeast models Saccharomyces cerevisiae and Schizosaccharomyces pombe, pheromonal communication activates similar pathways composed of cognate G-protein-coupled receptors and downstream small GTPase Cdc42 and MAP kinase cascades. Local pheromone release and sensing, at a mobile surface polarity patch, underlie spatial gradient interpretation to form pairs between two cells of distinct mating types. Concentration of secretion at the point of cell-cell contact then leads to local cell wall digestion for cell fusion, forming a diploid zygote that prevents further fusion attempts. A number of asymmetries between mating types may promote efficiency of the system. In this review, we present our current knowledge of pheromone signaling in the two model yeasts, with an emphasis on how cells decode the pheromone signal spatially and ultimately fuse together. Though overall pathway architectures are similar in the two species, their large evolutionary distance allows to explore how conceptually similar solutions to a general biological problem can arise from divergent molecular components.
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Nitika, Zheng B, Ruan L, Kline JT, Omkar S, Sikora J, Texeira Torres M, Wang Y, Takakuwa JE, Huguet R, Klemm C, Segarra VA, Winters MJ, Pryciak PM, Thorpe PH, Tatebayashi K, Li R, Fornelli L, Truman AW. Comprehensive characterization of the Hsp70 interactome reveals novel client proteins and interactions mediated by posttranslational modifications. PLoS Biol 2022; 20:e3001839. [PMID: 36269765 PMCID: PMC9629621 DOI: 10.1371/journal.pbio.3001839] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 11/02/2022] [Accepted: 09/21/2022] [Indexed: 01/06/2023] Open
Abstract
Hsp70 interactions are critical for cellular viability and the response to stress. Previous attempts to characterize Hsp70 interactions have been limited by their transient nature and the inability of current technologies to distinguish direct versus bridged interactions. We report the novel use of cross-linking mass spectrometry (XL-MS) to comprehensively characterize the Saccharomyces cerevisiae (budding yeast) Hsp70 protein interactome. Using this approach, we have gained fundamental new insights into Hsp70 function, including definitive evidence of Hsp70 self-association as well as multipoint interaction with its client proteins. In addition to identifying a novel set of direct Hsp70 interactors that can be used to probe chaperone function in cells, we have also identified a suite of posttranslational modification (PTM)-associated Hsp70 interactions. The majority of these PTMs have not been previously reported and appear to be critical in the regulation of client protein function. These data indicate that one of the mechanisms by which PTMs contribute to protein function is by facilitating interaction with chaperones. Taken together, we propose that XL-MS analysis of chaperone complexes may be used as a unique way to identify biologically important PTMs on client proteins.
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Affiliation(s)
- Nitika
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States America
| | - Bo Zheng
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States America
| | - Linhao Ruan
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
| | - Jake T. Kline
- Department of Biology, University of Oklahoma, Norman, Oklahoma, United States America
| | - Siddhi Omkar
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States America
| | - Jacek Sikora
- Department of Molecular Biosciences, Department of Chemistry, and the Feinberg School of Medicine, Northwestern University, Evanston, Illinois, United States America
| | - Mara Texeira Torres
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Yuhao Wang
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
| | - Jade E. Takakuwa
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States America
| | - Romain Huguet
- Thermo Scientific, San Jose, California, United States America
| | - Cinzia Klemm
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Verónica A. Segarra
- Departments of Biological Sciences and Chemistry, Goucher College, Baltimore, Maryland, United States America
| | - Matthew J. Winters
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States America
| | - Peter M. Pryciak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States America
| | - Peter H. Thorpe
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Kazuo Tatebayashi
- Laboratory of Molecular Genetics, Frontier Research Unit, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Rong Li
- Center for Cell Dynamics and Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States America
- Mechanobiology Institute and Department of Biological Sciences, National University of Singapore, Singapore
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, United States America
| | - Luca Fornelli
- Department of Biology, University of Oklahoma, Norman, Oklahoma, United States America
| | - Andrew W. Truman
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, North Carolina, United States America
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10
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de Nadal E, Posas F. OUP accepted manuscript. FEMS Yeast Res 2022; 22:6543702. [PMID: 35254447 PMCID: PMC8953452 DOI: 10.1093/femsyr/foac013] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/03/2022] [Indexed: 11/15/2022] Open
Affiliation(s)
- Eulàlia de Nadal
- Corresponding author: Institute for Research in Biomedicine (IRB Barcelona) Parc Científic de Barcelona c/ Baldiri Reixac, 10. 08028 Barcelona - Spain. E-mail:
| | - Francesc Posas
- Corresponding author: Institute for Research in Biomedicine (IRB Barcelona) Parc Científic de Barcelona c/ Baldiri Reixac, 10. 08028 Barcelona - Spain. E-mail:
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11
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Cdc42-Specific GTPase-Activating Protein Rga1 Squelches Crosstalk between the High-Osmolarity Glycerol (HOG) and Mating Pheromone Response MAPK Pathways. Biomolecules 2021; 11:biom11101530. [PMID: 34680163 PMCID: PMC8533825 DOI: 10.3390/biom11101530] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 11/25/2022] Open
Abstract
Eukaryotes utilize distinct mitogen/messenger-activated protein kinase (MAPK) pathways to evoke appropriate responses when confronted with different stimuli. In yeast, hyperosmotic stress activates MAPK Hog1, whereas mating pheromones activate MAPK Fus3 (and MAPK Kss1). Because these pathways share several upstream components, including the small guanosine-5'-triphosphate phosphohydrolase (GTPase) cell-division-cycle-42 (Cdc42), mechanisms must exist to prevent inadvertent cross-pathway activation. Hog1 activity is required to prevent crosstalk to Fus3 and Kss1. To identify other factors required to maintain signaling fidelity during hypertonic stress, we devised an unbiased genetic selection for mutants unable to prevent such crosstalk even when active Hog1 is present. We repeatedly isolated truncated alleles of RGA1, a Cdc42-specific GTPase-activating protein (GAP), each lacking its C-terminal catalytic domain, that permit activation of the mating MAPKs under hyperosmotic conditions despite Hog1 being present. We show that Rga1 down-regulates Cdc42 within the high-osmolarity glycerol (HOG) pathway, but not the mating pathway. Because induction of mating pathway output via crosstalk from the HOG pathway takes significantly longer than induction of HOG pathway output, our findings suggest that, under normal conditions, Rga1 contributes to signal insulation by limiting availability of the GTP-bound Cdc42 pool generated by hypertonic stress. Thus, Rga1 action contributes to squelching crosstalk by imposing a type of “kinetic proofreading”. Although Rga1 is a Hog1 substrate in vitro, we eliminated the possibility that its direct Hog1-mediated phosphorylation is necessary for its function in vivo. Instead, we found first that, like its paralog Rga2, Rga1 is subject to inhibitory phosphorylation by the S. cerevisiae cyclin-dependent protein kinase 1 (Cdk1) ortholog Cdc28 and that hyperosmotic shock stimulates its dephosphorylation and thus Rga1 activation. Second, we found that Hog1 promotes Rga1 activation by blocking its Cdk1-mediated phosphorylation, thereby allowing its phosphoprotein phosphatase 2A (PP2A)-mediated dephosphorylation. These findings shed light on why Hog1 activity is required to prevent crosstalk from the HOG pathway to the mating pheromone response pathway.
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12
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Grinhagens S, Dünkler A, Wu Y, Rieger L, Brenner P, Gronemeyer T, Mulaw MA, Johnsson N. A time-resolved interaction analysis of Bem1 reconstructs the flow of Cdc42 during polar growth. Life Sci Alliance 2020; 3:e202000813. [PMID: 32737079 PMCID: PMC7409549 DOI: 10.26508/lsa.202000813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/16/2022] Open
Abstract
Cdc42 organizes cellular polarity and directs the formation of cellular structures in many organisms. By locating Cdc24, the source of active Cdc42, to the growing front of the yeast cell, the scaffold protein Bem1, is instrumental in shaping the cellular gradient of Cdc42. This gradient instructs bud formation, bud growth, or cytokinesis through the actions of a diverse set of effector proteins. To address how Bem1 participates in these transformations, we systematically tracked its protein interactions during one cell cycle to define the ensemble of Bem1 interaction states for each cell cycle stage. Mutants of Bem1 that interact with only a discrete subset of the interaction partners allowed to assign specific functions to different interaction states and identified the determinants for their cellular distributions. The analysis characterizes Bem1 as a cell cycle-specific shuttle that distributes active Cdc42 from its source to its effectors. It further suggests that Bem1 might convert the PAKs Cla4 and Ste20 into their active conformations.
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Affiliation(s)
- Sören Grinhagens
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Alexander Dünkler
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Yehui Wu
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Lucia Rieger
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Philipp Brenner
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Thomas Gronemeyer
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
| | - Medhanie A Mulaw
- Comprehensive Cancer Center Ulm, Institute of Experimental Cancer Research, Ulm University, Ulm, Germany
| | - Nils Johnsson
- Department of Biology, Institute of Molecular Genetics and Cell Biology, Ulm University, Ulm, Germany
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13
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Vázquez-Ibarra A, Rodríguez-Martínez G, Guerrero-Serrano G, Kawasaki L, Ongay-Larios L, Coria R. Negative feedback-loop mechanisms regulating HOG- and pheromone-MAPK signaling in yeast. Curr Genet 2020; 66:867-880. [PMID: 32564133 DOI: 10.1007/s00294-020-01089-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 11/28/2022]
Abstract
The pheromone response and the high osmolarity glycerol (HOG) pathways are considered the prototypical MAPK signaling systems. They are the best-understood pathways in eukaryotic cells, yet they continue to provide insights in how cells relate with the environment. These systems are subjected to tight regulatory circuits to prevent hyperactivation in length and intensity. Failure to do this may be a matter of life or death specially for unicellular organisms such as Saccharomyces cerevisiae. The signaling pathways are fine-tuned by positive and negative feedback loops exerted by pivotal control elements that allow precise responses to specific stimuli, despite the fact that some elements of the systems are common to different signaling pathways. Here we describe the experimentally proven negative feedback loops that modulate the pheromone response and the HOG pathways. As described in this review, MAP kinases are central mechanistic components of these feedback loops. They have the capacity to modulate basal signaling activity, a fast extranuclear response, and a longer-lasting transcriptional process.
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Affiliation(s)
- Araceli Vázquez-Ibarra
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México City, México
| | - Griselda Rodríguez-Martínez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México City, México
| | | | - Laura Kawasaki
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México City, México
| | - Laura Ongay-Larios
- Unidad de Biología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México City, México
| | - Roberto Coria
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, México City, México.
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14
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Van Drogen F, Dard N, Pelet S, Lee SS, Mishra R, Srejić N, Peter M. Crosstalk and spatiotemporal regulation between stress-induced MAP kinase pathways and pheromone signaling in budding yeast. Cell Cycle 2020; 19:1707-1715. [PMID: 32552303 DOI: 10.1080/15384101.2020.1779469] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Budding yeast, Saccharomyces cerevisiae, has been widely used as a model system to study cellular signaling in response to internal and external cues. Yeast was among the first organisms in which the architecture, feedback mechanisms and physiological responses of various MAP kinase signaling cascades were studied in detail. Although these MAP kinase pathways are activated by different signals and elicit diverse cellular responses, such as adaptation to stress and mating, they function as an interconnected signaling network, as they influence each other and, in some cases, even share components. Indeed, various stress signaling pathways interfere with pheromone signaling that triggers a distinct cellular differentiation program. However, the molecular mechanisms responsible for this crosstalk are still poorly understood. Here, we review the general topology of the yeast MAP kinase signaling network and highlight recent and new data revealing how conflicting intrinsic and extrinsic signals are interpreted to orchestrate appropriate cellular responses.
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Affiliation(s)
| | - Nicolas Dard
- Ufr Smbh, University Sorbonne Paris Nord , Bobigny, France
| | - Serge Pelet
- Department of Fundamental Microbiology, University of Lausanne , Lausanne, Switzerland
| | - Sung Sik Lee
- ETH Zürich, Institute for Biochemistry , Zürich, Switzerland.,ETH Zürich, Scientific Center for Optical and Electron Microscopy (ScopeM) , Zürich, Switzerland
| | - Ranjan Mishra
- ETH Zürich, Institute for Biochemistry , Zürich, Switzerland
| | - Nevena Srejić
- ETH Zürich, Institute for Biochemistry , Zürich, Switzerland
| | - Matthias Peter
- ETH Zürich, Institute for Biochemistry , Zürich, Switzerland
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15
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Tatebayashi K, Yamamoto K, Tomida T, Nishimura A, Takayama T, Oyama M, Kozuka-Hata H, Adachi-Akahane S, Tokunaga Y, Saito H. Osmostress enhances activating phosphorylation of Hog1 MAP kinase by mono-phosphorylated Pbs2 MAP2K. EMBO J 2020; 39:e103444. [PMID: 32011004 PMCID: PMC7049814 DOI: 10.15252/embj.2019103444] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/22/2019] [Accepted: 01/08/2020] [Indexed: 12/21/2022] Open
Abstract
The MAP kinase (MAPK) Hog1 is the central regulator of osmoadaptation in yeast. When cells are exposed to high osmolarity, the functionally redundant Sho1 and Sln1 osmosensors, respectively, activate the Ste11‐Pbs2‐Hog1 MAPK cascade and the Ssk2/Ssk22‐Pbs2‐Hog1 MAPK cascade. In a canonical MAPK cascade, a MAPK kinase kinase (MAP3K) activates a MAPK kinase (MAP2K) by phosphorylating two conserved Ser/Thr residues in the activation loop. Here, we report that the MAP3K Ste11 phosphorylates only one activating phosphorylation site (Thr‐518) in Pbs2, whereas the MAP3Ks Ssk2/Ssk22 can phosphorylate both Ser‐514 and Thr‐518 under optimal osmostress conditions. Mono‐phosphorylated Pbs2 cannot phosphorylate Hog1 unless the reaction between Pbs2 and Hog1 is enhanced by osmostress. The lack of the osmotic enhancement of the Pbs2‐Hog1 reaction suppresses Hog1 activation by basal MAP3K activities and prevents pheromone‐to‐Hog1 crosstalk in the absence of osmostress. We also report that the rapid‐and‐transient Hog1 activation kinetics at mildly high osmolarities and the slow and prolonged activation kinetics at severely high osmolarities are both caused by a common feedback mechanism.
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Affiliation(s)
- Kazuo Tatebayashi
- Laboratory of Molecular Genetics, Frontier Research Unit, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Katsuyoshi Yamamoto
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Taichiro Tomida
- Department of Physiology, School of Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Akiko Nishimura
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Tomomi Takayama
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masaaki Oyama
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Hiroko Kozuka-Hata
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Satomi Adachi-Akahane
- Department of Physiology, School of Medicine, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Yuji Tokunaga
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Haruo Saito
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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16
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Joshua IM, Höfken T. Ste20 and Cla4 modulate the expression of the glycerol biosynthesis enzyme Gpd1 by a novel MAPK-independent pathway. Biochem Biophys Res Commun 2019; 517:611-616. [PMID: 31395335 DOI: 10.1016/j.bbrc.2019.07.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/19/2019] [Indexed: 11/29/2022]
Abstract
p21-activated kinases (PAKs) are important signalling molecules with a wide range of functions. In budding yeast, the main PAKs Ste20 and Cla4 regulate the response to hyperosmotic stress, which is an excellent model for the adaptation to changing environmental conditions. In this pathway, the only known function of Ste20 and Cla4 is the activation of a mitogen-activated protein kinase (MAPK) cascade through Ste11. This eventually leads to increased transcription of glycerol biosynthesis genes, the most important response to hyperosmotic shock. Here, we show that Ste20 and Cla4 not only stimulate transcription, they also bind to the glycerol biosynthesis enzymes Gpd1, Gpp1 and Gpp2. Protein levels of Gpd1, the enzyme that catalyzes the rate limiting step in glycerol synthesis, positively correlate with glucose availability. Using a chemical genetics approach, we find that simultaneous inactivation of STE20 and CLA4 reduces the glucose-induced increase of Gpd1 levels, whereas the deletion of either STE20 or CLA4 alone has no effect. This is also observed for the hyperosmotic stress-induced increase of Gpd1 levels. Importantly, under both conditions the deletion of STE11 has no effect on Gpd1 induction. These observations suggest that Ste20 and Cla4 not only have a role in the transcriptional regulation of GPD1 through Ste11. They also seem to modulate GPD1 expression at another level such as translation or protein degradation.
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Affiliation(s)
| | - Thomas Höfken
- Division of Biosciences, Brunel University London, UK.
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17
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Mutlu N, Sheidy DT, Hsu A, Jeong HS, Wozniak KJ, Kumar A. A Stress-Responsive Signaling Network Regulating Pseudohyphal Growth and Ribonucleoprotein Granule Abundance in Saccharomyces cerevisiae. Genetics 2019; 213:705-720. [PMID: 31455721 PMCID: PMC6781900 DOI: 10.1534/genetics.119.302538] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/21/2019] [Indexed: 11/18/2022] Open
Abstract
The budding yeast Saccharomyces cerevisiae undergoes a stress-responsive transition to a pseudohyphal growth form in which cells elongate and remain connected in multicellular filaments. Pseudohyphal growth is regulated through conserved signaling networks that control cell growth and the response to glucose or nitrogen limitation in metazoans. These networks are incompletely understood, and our studies identify the TORC1- and PKA-regulated kinase Ksp1p as a key stress-responsive signaling effector in the yeast pseudohyphal growth response. The kinase-defective ksp1-K47D allele results in decreased pseudohyphal morphology at the cellular and colony level, indicating that Ksp1p kinase signaling is required for pseudohyphal filamentation. To determine the functional consequences of Ksp1p signaling, we implemented transcriptional profiling and quantitative phosphoproteomic analysis of ksp1-K47D on a global scale. Ksp1p kinase signaling maintains wild-type transcript levels of many pathways for amino acid synthesis and metabolism, relevant for the regulation of translation under conditions of nutrient stress. Proteins in stress-responsive ribonucleoprotein granules are regulated post-translationally by Ksp1p, and the Ksp1p-dependent phosphorylation sites S176 in eIF4G/Tif4631p and S436 in Pbp1p are required for wild-type levels of pseudohyphal growth and Protein Kinase A pathway activity. Pbp1p and Tif4631p localize in stress granules, and the ksp1 null mutant shows elevated abundance of Pbp1p puncta relative to wild-type. Collectively, the Ksp1p kinase signaling network integrates polarized pseudohyphal morphogenesis and translational regulation through the stress-responsive transcriptional control of pathways for amino acid metabolism and post-translational modification of translation factors affecting stress granule abundance.
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Affiliation(s)
- Nebibe Mutlu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Daniel T Sheidy
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | | | - Han Seol Jeong
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Katherine J Wozniak
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
- Program in Molecular and Cellular Biology, University of Michigan, Ann Arbor, Michigan 48109
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18
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Chen T, Wagner AS, Tams RN, Eyer JE, Kauffman SJ, Gann ER, Fernandez EJ, Reynolds TB. Lrg1 Regulates β (1,3)-Glucan Masking in Candida albicans through the Cek1 MAP Kinase Pathway. mBio 2019; 10:e01767-19. [PMID: 31530671 PMCID: PMC6751057 DOI: 10.1128/mbio.01767-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/15/2019] [Indexed: 12/28/2022] Open
Abstract
Candida albicans is among the most prevalent opportunistic human fungal pathogens. The ability to mask the immunogenic polysaccharide β (1,3)-glucan from immune detection via a layer of mannosylated proteins is a key virulence factor of C. albicans We previously reported that hyperactivation of the Cek1 mitogen-activated protein (MAP) kinase pathway promotes β (1,3)-glucan exposure. In this communication, we report a novel upstream regulator of Cek1 activation and characterize the impact of Cek1 activity on fungal virulence. Lrg1 encodes a GTPase-activating protein (GAP) that has been suggested to inhibit the GTPase Rho1. We found that disruption of LRG1 causes Cek1 hyperactivation and β (1,3)-glucan unmasking. However, when GTPase activation was measured for a panel of GTPases, the lrg1ΔΔ mutant exhibited increased activation of Cdc42 and Ras1 but not Rho1 or Rac1. Unmasking and Cek1 activation in the lrg1ΔΔ mutant can be blocked by inhibition of the Ste11 MAP kinase kinase kinase (MAPKKK), indicating that the lrg1ΔΔ mutant acts through the canonical Cek1 MAP kinase cascade. In order to determine how Cek1 hyperactivation specifically impacts virulence, a doxycycline-repressible hyperactive STE11ΔN467 allele was expressed in C. albicans In the absence of doxycycline, this allele overexpressed STE11ΔN467 , which induced production of proinflammatory tumor necrosis factor alpha (TNF-α) from murine macrophages. This in vitro phenotype correlates with decreased colonization and virulence in a mouse model of systemic infection. The mechanism by which Ste11ΔN467 causes unmasking was explored with RNA sequencing (RNA-Seq) analysis. Overexpression of Ste11ΔN467 caused upregulation of the Cph1 transcription factor and of a group of cell wall-modifying proteins which are predicted to impact cell wall architecture.IMPORTANCECandida albicans is an important source of systemic infections in humans. The ability to mask the immunogenic cell wall polymer β (1,3)-glucan from host immune surveillance contributes to fungal virulence. We previously reported that the hyperactivation of the Cek1 MAP kinase cascade promotes cell wall unmasking, thus increasing strain immunogenicity. In this study, we identified a novel regulator of the Cek1 pathway called Lrg1. Lrg1 is a predicted GTPase-activating protein (GAP) that represses Cek1 activity by downregulating the GTPase Cdc42 and its downstream MAPKKK, Ste11. Upregulation of Cek1 activity diminished fungal virulence in the mouse model of infection, and this correlates with increased cytokine responses from macrophages. We also analyzed the transcriptional profile determined during β (1,3)-glucan exposure driven by Cek1 hyperactivation. Our report provides a model where Cek1 hyperactivation causes β (1,3)-glucan exposure by upregulation of cell wall proteins and leads to more robust immune detection in vivo, promoting more effective clearance.
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Affiliation(s)
- Tian Chen
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Andrew S Wagner
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Robert N Tams
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
| | - James E Eyer
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Sarah J Kauffman
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Eric R Gann
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Elias J Fernandez
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Todd B Reynolds
- Department of Microbiology, The University of Tennessee, Knoxville, Tennessee, USA
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19
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van Drogen F, Mishra R, Rudolf F, Walczak MJ, Lee SS, Reiter W, Hegemann B, Pelet S, Dohnal I, Binolfi A, Yudina Z, Selenko P, Wider G, Ammerer G, Peter M. Mechanical stress impairs pheromone signaling via Pkc1-mediated regulation of the MAPK scaffold Ste5. J Cell Biol 2019; 218:3117-3133. [PMID: 31315942 PMCID: PMC6719448 DOI: 10.1083/jcb.201808161] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 04/23/2019] [Accepted: 06/19/2019] [Indexed: 01/10/2023] Open
Abstract
This study shows that Pkc1 inhibits yeast pheromone signaling upon intrinsic and extrinsic mechanical stress. Pkc1 phosphorylates the RING-H2 domains of the scaffolds Ste5 and Far1, thereby preventing their interaction with Gβγ at the plasma membrane. This crosstalk mechanism regulates polarized growth and cell–cell fusion during mating. Cells continuously adapt cellular processes by integrating external and internal signals. In yeast, multiple stress signals regulate pheromone signaling to prevent mating under unfavorable conditions. However, the underlying crosstalk mechanisms remain poorly understood. Here, we show that mechanical stress activates Pkc1, which prevents lysis of pheromone-treated cells by inhibiting polarized growth. In vitro Pkc1 phosphorylates conserved residues within the RING-H2 domains of the scaffold proteins Far1 and Ste5, which are also phosphorylated in vivo. Interestingly, Pkc1 triggers dispersal of Ste5 from mating projections upon mechanically induced stress and during cell–cell fusion, leading to inhibition of the MAPK Fus3. Indeed, RING phosphorylation interferes with Ste5 membrane association by preventing binding to the receptor-linked Gβγ protein. Cells expressing nonphosphorylatable Ste5 undergo increased lysis upon mechanical stress and exhibit defects in cell–cell fusion during mating, which is exacerbated by simultaneous expression of nonphosphorylatable Far1. These results uncover a mechanical stress–triggered crosstalk mechanism modulating pheromone signaling, polarized growth, and cell–cell fusion during mating.
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Affiliation(s)
| | - Ranjan Mishra
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Fabian Rudolf
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Michal J Walczak
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland
| | - Sung Sik Lee
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland.,Scientific Center for Optical and Electron Microscopy, ETH Zürich, Zürich, Switzerland
| | - Wolfgang Reiter
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Björn Hegemann
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Serge Pelet
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Ilse Dohnal
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Andres Binolfi
- Department of Nuclear Magnetic Resonance-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology, Berlin, Germany
| | - Zinaida Yudina
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Philipp Selenko
- Department of Nuclear Magnetic Resonance-Supported Structural Biology, Leibniz Institute of Molecular Pharmacology, Berlin, Germany
| | - Gerhard Wider
- Institute of Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland
| | - Gustav Ammerer
- Department of Biochemistry, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Matthias Peter
- Institute for Biochemistry, ETH Zürich, Zürich, Switzerland
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20
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Takayama T, Yamamoto K, Saito H, Tatebayashi K. Interaction between the transmembrane domains of Sho1 and Opy2 enhances the signaling efficiency of the Hog1 MAP kinase cascade in Saccharomyces cerevisiae. PLoS One 2019; 14:e0211380. [PMID: 30682143 PMCID: PMC6347418 DOI: 10.1371/journal.pone.0211380] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/12/2019] [Indexed: 12/23/2022] Open
Abstract
To cope with increased extracellular osmolarity, the budding yeast Saccharomyces cerevisiae activates the Hog1 mitogen-activated protein kinase (MAPK), which controls a variety of adaptive responses. Hog1 is activated through the high-osmolarity glycerol (HOG) pathway, which consists of a core MAPK cascade and two independent upstream branches (SHO1 and SLN1 branches) containing distinct osmosensing machineries. In the SHO1 branch, a homo-oligomer of Sho1, the four-transmembrane (TM) osmosensor, interacts with the transmembrane co-osmosensors, Hkr1 and Msb2, and the membrane anchor protein Opy2, through their TM domains, and activates the Ste20-Ste11-Pbs2-Hog1 kinase cascade. In this study, we isolated and analyzed hyperactive mutants of Sho1 and Opy2 that harbor mutations within their TM domains. Several hyperactive mutations enhanced the interaction between Sho1 and Opy2, indicating the importance of the TM-mediated interaction between Sho1 and Opy2 for facilitating effective signaling. The interaction between the TM domains of Sho1 and Opy2 will place their respective cytoplasmic binding partners Pbs2 and Ste11 in close proximity. Indeed, genetic analyses of the mutants showed that the Sho1-Opy2 interaction enhances the activation of Pbs2 by Ste11, but not Hog1 by Pbs2. Some of the hyperactive mutants had mutations at the extracellular ends of either Sho1 TM4 or Opy2 TM, and defined the Sho1-Opy2 binding site 1 (BS1). Chemical crosslinking and mutational analyses revealed that the cytoplasmic ends of Sho1 TM1 and Opy2 TM also interact with each other, defining the Sho1-Opy2 binding site 2 (BS2). A geometric consideration constrains that one Opy2 molecule must interact with two adjacent Sho1 molecules in Sho1 oligomer. These results raise a possibility that an alteration of the conformation of the Sho1-Opy2 complex might contributes to the osmotic activation of the Hog1 MAPK cascade.
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Affiliation(s)
- Tomomi Takayama
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Katsuyoshi Yamamoto
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Haruo Saito
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Kazuo Tatebayashi
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Laboratory of Molecular Genetics, Frontier Research Unit, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- * E-mail:
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21
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Gomes EV, Bortolossi JC, Sanches PR, Mendes NS, Martinez-Rossi NM, Rossi A. STE20/PAKA Protein Kinase Gene Releases an Autoinhibitory Domain through Pre-mRNA Alternative Splicing in the Dermatophyte Trichophyton rubrum. Int J Mol Sci 2018; 19:ijms19113654. [PMID: 30463281 PMCID: PMC6274995 DOI: 10.3390/ijms19113654] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/30/2018] [Accepted: 11/16/2018] [Indexed: 12/31/2022] Open
Abstract
Signaling pathways are highly diverse in filamentous fungi, allowing the cells to receive and process ambient information. Interaction of components from different pathways results in signaling networks. The mitogen-activated protein kinase (MAPK) pathway is dependent on phosphorylation that is accomplished by kinase proteins. Thus, the STE/PAK protein kinase family plays essential roles in MAPK signal transduction, regulating several cellular functions. The STE/PAK protein displays an autoinhibitory (Cdc42/Rac interactive binding-CRIB) domain on its N-terminal portion, which interacts with the C-terminal catalytic kinase domain. Based on current knowledge, for the STE/PAK kinase to be activated, molecular signals (e.g., interaction with the activated form of Rac1 and Cdc42 proteins) or proteolytic cleavage by caspase 3 is necessary. Both mechanisms release the kinase domain from the CRIB interaction. Here, we hypothesize a novel molecular mechanism for the activation of STE20/PAKA kinase in Trichophyton rubrum based on an alternative pre-mRNA splicing process. Our data suggest that, because of the retention of intron 1 of this gene, it is theoretically possible that the translation of STE20/PAKA kinase will be free of its autoinhibitory CRIB domain. These findings indicate a rapid response system to environmental changes. Furthermore, STE20/PAKA may be a potential T. rubrum virulence factor and an interesting target for new drugs against dermatophytes.
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Affiliation(s)
- Eriston V Gomes
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
- Department of Biofunctional, Center of Higher Education Morgana Potrich Eireli, Morgana Potrich College, Mineiros, Goiás 75830-000, Brazil.
| | - Julio C Bortolossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
| | - Niege S Mendes
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
| | - Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, São Paulo University, Ribeirão Preto, São Paulo 14049-900, Brazil.
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22
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Winters MJ, Pryciak PM. Analysis of the thresholds for transcriptional activation by the yeast MAP kinases Fus3 and Kss1. Mol Biol Cell 2018; 29:669-682. [PMID: 29321252 PMCID: PMC6004581 DOI: 10.1091/mbc.e17-10-0578] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/19/2017] [Accepted: 01/03/2018] [Indexed: 12/31/2022] Open
Abstract
Signaling in the pheromone response pathway of budding yeast activates two distinct MAP kinases (MAPKs), Fus3 and Kss1. Either MAPK alone can mediate pheromone-induced transcription, but it has been unclear to what degree each one contributes to transcriptional output in wild-type cells. Here, we report that transcription reflects the ratio of active to inactive MAPK, and not simply the level of active MAPK. For Kss1 the majority of MAPK molecules must be converted to the active form, whereas for Fus3 only a small minority must be activated. These different activation thresholds reflect two opposing effects of each MAPK, in which the inactive forms inhibit transcription, whereas the active forms promote transcription. Moreover, negative feedback from Fus3 limits activation of Kss1 so that it does not meet its required threshold in wild-type cells but does so only when hyperactivated in cells lacking Fus3. The results suggest that the normal transcriptional response involves asymmetric contributions from the two MAPKs, in which pheromone signaling reduces the negative effect of Kss1 while increasing the positive effect of Fus3. These findings reveal new functional distinctions between these MAPKs, and help illuminate how inhibitory functions shape positive pathway outputs in both pheromone and filamentation pathways.
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Affiliation(s)
- Matthew J Winters
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Peter M Pryciak
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
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23
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Auesukaree C. Molecular mechanisms of the yeast adaptive response and tolerance to stresses encountered during ethanol fermentation. J Biosci Bioeng 2017; 124:133-142. [PMID: 28427825 DOI: 10.1016/j.jbiosc.2017.03.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/16/2017] [Indexed: 12/28/2022]
Abstract
During ethanol fermentation, yeast cells encounter various stresses including sugar substrates-induced high osmolarity, increased ethanol concentration, oxygen metabolism-derived reactive oxygen species (ROS), and elevated temperature. To cope with these fermentation-associated stresses, appropriate adaptive responses are required to prevent stress-induced cellular dysfunctions and to acquire stress tolerances. This review will focus on the cellular effects of these stresses, molecular basis of the adaptive response to each stress, and the cellular mechanisms contributing to stress tolerance. Since a single stress can cause diverse effects, including specific and non-specific effects, both specific and general stress responses are needed for achieving comprehensive protection. For instance, the high-osmolarity glycerol (HOG) pathway and the Yap1/Skn7-mediated pathways are specifically involved in responses to osmotic and oxidative stresses, respectively. On the other hand, due to the common effect of these stresses on disturbing protein structures, the upregulation of heat shock proteins (HSPs) and trehalose is induced upon exposures to all of these stresses. A better understanding of molecular mechanisms underlying yeast tolerance to these fermentation-associated stresses is essential for improvement of yeast stress tolerance by genetic engineering approaches.
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Affiliation(s)
- Choowong Auesukaree
- Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education, Bangkok 10400, Thailand.
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24
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Atay O, Skotheim JM. Spatial and temporal signal processing and decision making by MAPK pathways. J Cell Biol 2017; 216:317-330. [PMID: 28043970 PMCID: PMC5294789 DOI: 10.1083/jcb.201609124] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/25/2016] [Accepted: 12/12/2016] [Indexed: 01/14/2023] Open
Abstract
Recent studies show that MAPK pathways perform exquisite spatial and temporal signal processing. This review discusses the mechanisms that process dynamic inputs into graded output responses, the role of positive and negative feedbacks, and feedforward regulation. Mitogen-activated protein kinase (MAPK) pathways are conserved from yeast to man and regulate a variety of cellular processes, including proliferation and differentiation. Recent developments show how MAPK pathways perform exquisite spatial and temporal signal processing and underscores the importance of studying the dynamics of signaling pathways to understand their physiological response. The importance of dynamic mechanisms that process input signals into graded downstream responses has been demonstrated in the pheromone-induced and osmotic stress–induced MAPK pathways in yeast and in the mammalian extracellular signal-regulated kinase MAPK pathway. Particularly, recent studies in the yeast pheromone response have shown how positive feedback generates switches, negative feedback enables gradient detection, and coherent feedforward regulation underlies cellular memory. More generally, a new wave of quantitative single-cell studies has begun to elucidate how signaling dynamics determine cell physiology and represents a paradigm shift from descriptive to predictive biology.
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Affiliation(s)
- Oguzhan Atay
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305
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25
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Single-cell dynamics and variability of MAPK activity in a yeast differentiation pathway. Proc Natl Acad Sci U S A 2016; 113:E5896-E5905. [PMID: 27651485 DOI: 10.1073/pnas.1610081113] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In response to pheromones, yeast cells activate a MAPK pathway to direct processes important for mating, including gene induction, cell-cycle arrest, and polarized cell growth. Although a variety of assays have been able to elucidate signaling activities at multiple steps in the pathway, measurements of MAPK activity during the pheromone response have remained elusive, and our understanding of single-cell signaling behavior is incomplete. Using a yeast-optimized FRET-based mammalian Erk-activity reporter to monitor Fus3 and Kss1 activity in live yeast cells, we demonstrate that overall mating MAPK activity exhibits distinct temporal dynamics, rapid reversibility, and a graded dose dependence around the KD of the receptor, where phenotypic transitions occur. The complex dose response was found to be largely a consequence of two feedbacks involving cyclin-mediated scaffold phosphorylation and Fus3 autoregulation. Distinct cell cycle-dependent response patterns comprised a large portion of the cell-to-cell variability at each dose, constituting the major source of extrinsic noise in coupling activity to downstream gene-expression responses. Additionally, we found diverse spatial MAPK activity patterns to emerge over time in cells undergoing default, gradient, and true mating responses. Furthermore, ramping up and rapid loss of activity were closely associated with zygote formation in mating-cell pairs, supporting a role for elevated MAPK activity in successful cell fusion and morphogenic reorganization. Altogether, these findings present a detailed view of spatiotemporal MAPK activity during the pheromone response, elucidating its role in mediating complex long-term developmental fates in a unicellular differentiation system.
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26
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Konte T, Terpitz U, Plemenitaš A. Reconstruction of the High-Osmolarity Glycerol (HOG) Signaling Pathway from the Halophilic Fungus Wallemia ichthyophaga in Saccharomyces cerevisiae. Front Microbiol 2016; 7:901. [PMID: 27379041 PMCID: PMC4904012 DOI: 10.3389/fmicb.2016.00901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/26/2016] [Indexed: 11/13/2022] Open
Abstract
The basidiomycetous fungus Wallemia ichthyophaga grows between 1.7 and 5.1 M NaCl and is the most halophilic eukaryote described to date. Like other fungi, W. ichthyophaga detects changes in environmental salinity mainly by the evolutionarily conserved high-osmolarity glycerol (HOG) signaling pathway. In Saccharomyces cerevisiae, the HOG pathway has been extensively studied in connection to osmotic regulation, with a valuable knock-out strain collection established. In the present study, we reconstructed the architecture of the HOG pathway of W. ichthyophaga in suitable S. cerevisiae knock-out strains, through heterologous expression of the W. ichthyophaga HOG pathway proteins. Compared to S. cerevisiae, where the Pbs2 (ScPbs2) kinase of the HOG pathway is activated via the SHO1 and SLN1 branches, the interactions between the W. ichthyophaga Pbs2 (WiPbs2) kinase and the W. ichthyophaga SHO1 branch orthologs are not conserved: as well as evidence of poor interactions between the WiSho1 Src-homology 3 (SH3) domain and the WiPbs2 proline-rich motif, the absence of a considerable part of the osmosensing apparatus in the genome of W. ichthyophaga suggests that the SHO1 branch components are not involved in HOG signaling in this halophilic fungus. In contrast, the conserved activation of WiPbs2 by the S. cerevisiae ScSsk2/ScSsk22 kinase and the sensitivity of W. ichthyophaga cells to fludioxonil, emphasize the significance of two-component (SLN1-like) signaling via Group III histidine kinase. Combined with protein modeling data, our study reveals conserved and non-conserved protein interactions in the HOG signaling pathway of W. ichthyophaga and therefore significantly improves the knowledge of hyperosmotic signal processing in this halophilic fungus.
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Affiliation(s)
- Tilen Konte
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana Ljubljana, Slovenia
| | - Ulrich Terpitz
- Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University of Würzburg Würzburg, Germany
| | - Ana Plemenitaš
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana Ljubljana, Slovenia
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27
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Ge Y, Wang Y, Liu Y, Tan Y, Ren X, Zhang X, Hyde KD, Liu Y, Liu Z. Comparative genomic and transcriptomic analyses of the Fuzhuan brick tea-fermentation fungus Aspergillus cristatus. BMC Genomics 2016; 17:428. [PMID: 27267057 PMCID: PMC4895823 DOI: 10.1186/s12864-016-2637-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/22/2016] [Indexed: 02/07/2023] Open
Abstract
Background Aspergillus cristatus is the dominant fungus involved in the fermentation of Chinese Fuzhuan brick tea. Aspergillus cristatus is a homothallic fungus that undergoes a sexual stage without asexual conidiation when cultured in hypotonic medium. The asexual stage is induced by a high salt concentration, which completely inhibits sexual development. The taxon is therefore appropriate for investigating the mechanisms of asexual and sexual reproduction in fungi. In this study, de novo genome sequencing and analysis of transcriptomes during culture under high- and low-osmolarity conditions were performed. These analyses facilitated investigation of the evolution of mating-type genes, which determine the mode of sexual reproduction, in A. cristatus, the response of the high-osmolarity glycerol (HOG) pathway to osmotic stimulation, and the detection of mycotoxins and evaluation of the relationship with the location of the encoding genes. Results The A. cristatus genome comprised 27.9 Mb and included 68 scaffolds, from which 10,136 protein-coding gene models were predicted. A phylogenetic analysis suggested a considerable phylogenetic distance between A. cristatus and A. nidulans. Comparison of the mating-type gene loci among Aspergillus species indicated that the mode in A. cristatus differs from those in other Aspergillus species. The components of the HOG pathway were conserved in the genome of A. cristatus. Differential gene expression analysis in A. cristatus using RNA-Seq demonstrated that the expression of most genes in the HOG pathway was unaffected by osmotic pressure. No gene clusters associated with the production of carcinogens were detected. Conclusions A model of the mating-type locus in A. cristatus is reported for the first time. Aspergillus cristatus has evolved various mechanisms to cope with high osmotic stress. As a fungus associated with Fuzhuan tea, it is considered to be safe under low- and high-osmolarity conditions. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2637-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yongyi Ge
- College of Agriculture, Guizhou University, Guiyang, Guizhou, 550025, China.,Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China.,College of Life and Science, Guizhou University, Guiyang, Guizhou, 550025, China
| | - Yuchen Wang
- Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China.,Guizhou Institute of Biotechnology, Guiyang, Guizhou, 550006, China
| | - YongXiang Liu
- Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China.,Guizhou Institute of Biotechnology, Guiyang, Guizhou, 550006, China
| | - Yumei Tan
- Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China.,Guizhou Institute of Biotechnology, Guiyang, Guizhou, 550006, China
| | - Xiuxiu Ren
- College of Agriculture, Guizhou University, Guiyang, Guizhou, 550025, China.,Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China.,Ecological Engineering College, Guizhou University of Engineering Science, Bijie, Guizhou, 551700, China
| | - Xinyu Zhang
- Institute of Microbiology, State Key Laboratory of Mycology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Kevin D Hyde
- Institute of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand
| | | | - Zuoyi Liu
- Guizhou Key Laboratory of Agricultural Biotechnology, Guiyang, Guizhou, 550006, China. .,Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, 550006, China.
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28
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Popov-Čeleketić D, Bianchi F, Ruiz SJ, Meutiawati F, Poolman B. A Plasma Membrane Association Module in Yeast Amino Acid Transporters. J Biol Chem 2016; 291:16024-37. [PMID: 27226538 DOI: 10.1074/jbc.m115.706770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Indexed: 12/22/2022] Open
Abstract
Amino acid permeases (AAPs) in the plasma membrane (PM) of Saccharomyces cerevisiae are responsible for the uptake of amino acids and involved in regulation of their cellular levels. Here, we report on a strong and complex module for PM association found in the C-terminal tail of AAPs. Using in silico analyses and mutational studies we found that the C-terminal sequences of Gap1, Bap2, Hip1, Tat1, Tat2, Mmp1, Sam3, Agp1, and Gnp1 are about 50 residues long, associate with the PM, and have features that discriminate them from the termini of organellar amino acid transporters. We show that this sequence (named PMasseq) contains an amphipathic α-helix and the FWC signature, which is palmitoylated by palmitoyltransferase Pfa4. Variations of PMasseq, found in different AAPs, lead to different mobilities and localization patterns, whereas the disruption of the sequence has an adverse effect on cell viability. We propose that PMasseq modulates the function and localization of AAPs along the PM. PMasseq is one of the most complex protein signals for plasma membrane association across species and can be used as a delivery vehicle for the PM.
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Affiliation(s)
- Dušan Popov-Čeleketić
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Frans Bianchi
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Stephanie J Ruiz
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Febrina Meutiawati
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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29
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Xiong J, Cui X, Yuan X, Yu X, Sun J, Gong Q. The Hippo/STE20 homolog SIK1 interacts with MOB1 to regulate cell proliferation and cell expansion in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1461-75. [PMID: 26685188 DOI: 10.1093/jxb/erv538] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Multicellular organisms co-ordinate cell proliferation and cell expansion to maintain organ growth. In animals, the Hippo tumor suppressor pathway is a master regulator of organ size. Central to this pathway is a kinase cascade composed of Hippo and Warts, and their activating partners Salvador and Mob1/Mats. In plants, the Mob1/Mats homolog MOB1A has been characterized as a regulator of cell proliferation and sporogenesis. Nonetheless, no Hippo homologs have been identified. Here we show that the Arabidopsis serine/threonine kinase 1 (SIK1) is a Hippo homolog, and that it interacts with MOB1A to control organ size. SIK1 complements the function of yeast Ste20 in bud site selection and mitotic exit. The sik1 null mutant is dwarf with reduced cell numbers, endoreduplication, and cell expansion. A yeast two-hybrid screen identified Mob1/Mats homologs MOB1A and MOB1B as SIK1-interacting partners. The interaction between SIK1 and MOB1 was found to be mediated by an N-terminal domain of SIK1 and was further confirmed by bimolecular fluorescence complementation. Interestingly, sik1 mob1a is arrested at the seedling stage, and overexpression of neither SIK1 in mob1a nor MOB1A in sik1 can rescue the dwarf phenotypes, suggesting that SIK1 and MOB1 may be components of a larger protein complex. Our results pave the way for constructing a complete Hippo pathway that controls organ growth in higher plants.
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Affiliation(s)
- Jie Xiong
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xuefei Cui
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiangrong Yuan
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiulian Yu
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jialei Sun
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Qingqiu Gong
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
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30
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Alvaro CG, Thorner J. Heterotrimeric G Protein-coupled Receptor Signaling in Yeast Mating Pheromone Response. J Biol Chem 2016; 291:7788-95. [PMID: 26907689 PMCID: PMC4824985 DOI: 10.1074/jbc.r116.714980] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The DNAs encoding the receptors that respond to the peptide mating pheromones of the budding yeast Saccharomyces cerevisiae were isolated in 1985, and were the very first genes for agonist-binding heterotrimeric G protein-coupled receptors (GPCRs) to be cloned in any organism. Now, over 30 years later, this yeast and its receptors continue to provide a pathfinding experimental paradigm for investigating GPCR-initiated signaling and its regulation, as described in this retrospective overview.
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Affiliation(s)
- Christopher G Alvaro
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Jeremy Thorner
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
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31
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Hu Z, Wang Y, Yu L, Mahanty SK, Mendoza N, Elion EA. Mapping regions in Ste5 that support Msn5-dependent and -independent nuclear export. Biochem Cell Biol 2016; 94:109-28. [PMID: 26824509 DOI: 10.1139/bcb-2015-0101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Careful control of the available pool of the MAPK scaffold Ste5 is important for mating-pathway activation and the prevention of inappropriate mating differentiation in haploid Saccharomyces cerevisiae. Ste5 shuttles constitutively through the nucleus, where it is degraded by a ubiquitin-dependent mechanism triggered by G1 CDK phosphorylation. Here we narrow-down regions of Ste5 that mediate nuclear export. Four regions in Ste5 relocalize SV40-TAgNLS-GFP-GFP from nucleus to cytoplasm. One region is N-terminal, dependent on exportin Msn5/Ste21/Kap142, and interacts with Msn5 in 2 hybrid assays independently of mating pheromone, Fus3, Kss1, Ptc1, the NLS/PM, and RING-H2. A second region overlaps the PH domain and Ste11 binding site and 2 others are on the vWA domain and include residues essential for MAPK activation. We find no evidence for dependence on Crm1/Xpo1, despite numerous potential nuclear export sequences (NESs) detected by LocNES and NetNES1.1 predictors. Thus, Msn5 (homolog of human Exportin-5) and one or more exportins or adaptor molecules besides Crm1/Xpo1 may regulate Ste5 through multiple recognition sites.
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Affiliation(s)
- Zhenhua Hu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Yunmei Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Lu Yu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sanjoy K Mahanty
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Natalia Mendoza
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Elaine A Elion
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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32
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Scaffold Protein Ahk1, Which Associates with Hkr1, Sho1, Ste11, and Pbs2, Inhibits Cross Talk Signaling from the Hkr1 Osmosensor to the Kss1 Mitogen-Activated Protein Kinase. Mol Cell Biol 2016; 36:1109-23. [PMID: 26787842 DOI: 10.1128/mcb.01017-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/14/2016] [Indexed: 12/22/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, osmostress activates the Hog1 mitogen-activated protein kinase (MAPK), which regulates diverse osmoadaptive responses. Hkr1 is a large, highly glycosylated, single-path transmembrane protein that is a putative osmosensor in one of the Hog1 upstream pathways termed the HKR1 subbranch. The extracellular region of Hkr1 contains both a positive and a negative regulatory domain. However, the function of the cytoplasmic domain of Hkr1 (Hkr1-cyto) is unknown. Here, using a mass spectrometric method, we identified a protein, termed Ahk1 (Associated with Hkr1), that binds to Hkr1-cyto. Deletion of the AHK1 gene (in the absence of other Hog1 upstream branches) only partially inhibited osmostress-induced Hog1 activation. In contrast, Hog1 could not be activated by constitutively active mutants of the Hog1 pathway signaling molecules Opy2 or Ste50 in ahk1Δ cells, whereas robust Hog1 activation occurred in AHK1(+) cells. In addition to Hkr1-cyto binding, Ahk1 also bound to other signaling molecules in the HKR1 subbranch, including Sho1, Ste11, and Pbs2. Although osmotic stimulation of Hkr1 does not activate the Kss1 MAPK, deletion of AHK1 allowed Hkr1 to activate Kss1 by cross talk. Thus, Ahk1 is a scaffold protein in the HKR1 subbranch and prevents incorrect signal flow from Hkr1 to Kss1.
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33
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Plant Raf-like kinase integrates abscisic acid and hyperosmotic stress signaling upstream of SNF1-related protein kinase2. Proc Natl Acad Sci U S A 2015; 112:E6388-96. [PMID: 26540727 DOI: 10.1073/pnas.1511238112] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Plant response to drought and hyperosmosis is mediated by the phytohormone abscisic acid (ABA), a sesquiterpene compound widely distributed in various embryophyte groups. Exogenous ABA as well as hyperosmosis activates the sucrose nonfermenting 1 (SNF1)-related protein kinase2 (SnRK2), which plays a central role in cellular responses against drought and dehydration, although the details of the activation mechanism are not understood. Analysis of a mutant of the moss Physcomitrella patens with reduced ABA sensitivity and reduced hyperosmosis tolerance revealed that a protein kinase designated "ARK" (for "ABA and abiotic stress-responsive Raf-like kinase") plays an essential role in the activation of SnRK2. ARK encoded by a single gene in P. patens belongs to the family of group B3 Raf-like MAP kinase kinase kinases (B3-MAPKKKs) mediating ethylene, disease resistance, and salt and sugar responses in angiosperms. Our findings indicate that ARK, as a novel regulatory component integrating ABA and hyperosmosis signals, represents the ancestral B3-MAPKKKs, which multiplied, diversified, and came to have specific functions in angiosperms.
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Qi L, Kim Y, Jiang C, Li Y, Peng Y, Xu JR. Activation of Mst11 and Feedback Inhibition of Germ Tube Growth in Magnaporthe oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:881-91. [PMID: 26057388 DOI: 10.1094/mpmi-12-14-0391-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Appressorium formation and invasive growth are two important steps in the infection cycle of Magnaporthe oryzae that are regulated by the Mst11-Mst7-Pmk1 mitogen-activated protein kinase (MAPK) pathway. However, the molecular mechanism involved in the activation of Mst11 MAPK kinase kinase is not clear in the rice blast fungus. In this study, we functionally characterized the regulatory region of Mst11 and its self-inhibitory binding. Deletion of the middle region of Mst11, which contains the Ras-association (RA) domain and two conserved phosphorylation sites (S453 and S458), blocked Pmk1 activation and appressorium formation. However, the MST11(ΔRA) transformant MRD-2 still formed appressoria, although it was reduced in virulence. Interestingly, over 50% of its germ tubes branched and formed two appressoria by 48 h, which was suppressed by treatments with exogenous cAMP. The G18V dominant active mutation enhanced the interaction of Ras2 with Mst11, suggesting that Mst11 has stronger interactions with the activated Ras2. Furthermore, deletion and site-directed mutagenesis analyses indicated that phosphorylation at S453 and S458 of Mst11 is important for appressorium formation and required for the activation of Pmk1. We also showed that the N-terminal region of Mst11 directly interacted with its kinase domain, and the S789G mutation reduced their interactions. Expression of the MST11(S789G) allele rescued the defect of the mst11 mutant in plant infection and resulted in the formation of appressoria on hydrophilic surfaces, suggesting the gain-of-function effect of the S789G mutation. Overall, our results indicate that the interaction of Mst11 with activated Ras2 and phosphorylation of S453 and S458 play regulatory roles in Mst11 activation and infection-related morphogenesis, possibly by relieving its self-inhibitory interaction between its N-terminal region and the C-terminal kinase domain. In addition, binding of Mst11 to Ras2 may be involved in the feedback inhibition of cAMP signaling and further differentiation of germ tubes after appressorium formation.
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Affiliation(s)
- Linlu Qi
- 1 MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing 100193, China
- 2 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, U.S.A
| | - Yangseon Kim
- 2 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, U.S.A
| | - Cong Jiang
- 2 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, U.S.A
- 3 NWAFU-PU Joint Research Center, Northwestern A&F University, Yangling, Shaanxi 712100, China
| | - Yang Li
- 2 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, U.S.A
| | - Youliang Peng
- 1 MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Jin-Rong Xu
- 2 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, U.S.A
- 3 NWAFU-PU Joint Research Center, Northwestern A&F University, Yangling, Shaanxi 712100, China
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Errede B, Vered L, Ford E, Pena MI, Elston TC. Pheromone-induced morphogenesis and gradient tracking are dependent on the MAPK Fus3 binding to Gα. Mol Biol Cell 2015; 26:3343-58. [PMID: 26179918 PMCID: PMC4569322 DOI: 10.1091/mbc.e15-03-0176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/08/2015] [Indexed: 12/20/2022] Open
Abstract
Unique roles are found for the MAPK Fus3 during the mating response of yeast. In particular, the interaction of Fus3 with the G-protein α-subunit is required for morphogenesis and gradient tracking and suppresses cell-to-cell variability between mating and chemotropic fates in a population of pheromone-responding cells. Mitogen-activated protein kinase (MAPK) pathways control many cellular processes, including differentiation and proliferation. These pathways commonly activate MAPK isoforms that have redundant or overlapping function. However, recent studies have revealed circumstances in which MAPK isoforms have specialized, nonoverlapping roles in differentiation. The mechanisms that underlie this specialization are not well understood. To address this question, we sought to establish regulatory mechanisms that are unique to the MAPK Fus3 in pheromone-induced mating and chemotropic fate transitions of the budding yeast Saccharomyces cerevisiae. Our investigations reveal a previously unappreciated role for inactive Fus3 as a potent negative regulator of pheromone-induced chemotropism. We show that this inhibitory role is dependent on inactive Fus3 binding to the α-subunit of the heterotrimeric G-protein. Further analysis revealed that the binding of catalytically active Fus3 to the G-protein is required for gradient tracking and serves to suppress cell-to-cell variability between mating and chemotropic fates in a population of pheromone-responding cells.
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Affiliation(s)
- Beverly Errede
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Lior Vered
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Eintou Ford
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Matthew I Pena
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599
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Ryu J, Park SH. Simple synthetic protein scaffolds can create adjustable artificial MAPK circuits in yeast and mammalian cells. Sci Signal 2015; 8:ra66. [PMID: 26126717 DOI: 10.1126/scisignal.aab3397] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
As hubs for eukaryotic cell signaling, scaffold proteins are attractive targets for engineering and manipulating signaling circuits. We designed synthetic scaffolds with a repeated PDZ domain that interacted with engineered kinases of the mitogen-activated protein kinase (MAPK) cascade involved in yeast mating to investigate how modular interactions mediate kinase cascades. The synthetic scaffolds functioned as logic gates of signaling circuits. We replaced the endogenous yeast scaffold Ste5 with designer scaffolds with a variable numbers of a PDZ domain that bound kinases or phosphatases engineered with a PDZ-binding motif. Although association with the membrane was necessary for pathway activity, surprisingly, mating responses occurred when the circuit contained a scaffold with only two PDZ domains, which could only bind two of the three kinases simultaneously. Additionally, the three tiers of the MAPK pathway exhibited decreasing positional plasticity from the top [MAPK kinase kinase (MAPKKK)] to the bottom (MAPK) tier such that binding of a MAPKKK, but not a MAPK, from the osmoregulatory pathway or protein kinase C pathway to the synthetic scaffold activated a reporter of the mating response. We also showed that the output duration and intensity could be altered by recruiting phosphatases or varying the affinity of the recruited proteins for the scaffold and that a designer MAPK scaffold functioned in mammalian cells. Thus, this synthetic approach with designer scaffolds should enable the rational manipulation or engineering of signaling pathways and provide insight into the functional roles of scaffold proteins.
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Affiliation(s)
- Jihoon Ryu
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea
| | - Sang-Hyun Park
- Department of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
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Vaga S, Bernardo-Faura M, Cokelaer T, Maiolica A, Barnes CA, Gillet LC, Hegemann B, van Drogen F, Sharifian H, Klipp E, Peter M, Saez-Rodriguez J, Aebersold R. Phosphoproteomic analyses reveal novel cross-modulation mechanisms between two signaling pathways in yeast. Mol Syst Biol 2014; 10:767. [PMID: 25492886 PMCID: PMC4300490 DOI: 10.15252/msb.20145112] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cells respond to environmental stimuli via specialized signaling pathways. Concurrent stimuli trigger multiple pathways that integrate information, predominantly via protein phosphorylation. Budding yeast responds to NaCl and pheromone via two mitogen-activated protein kinase cascades, the high osmolarity, and the mating pathways, respectively. To investigate signal integration between these pathways, we quantified the time-resolved phosphorylation site dynamics after pathway co-stimulation. Using shotgun mass spectrometry, we quantified 2,536 phosphopeptides across 36 conditions. Our data indicate that NaCl and pheromone affect phosphorylation events within both pathways, which thus affect each other at more levels than anticipated, allowing for information exchange and signal integration. We observed a pheromone-induced down-regulation of Hog1 phosphorylation due to Gpd1, Ste20, Ptp2, Pbs2, and Ptc1. Distinct Ste20 and Pbs2 phosphosites responded differently to the two stimuli, suggesting these proteins as key mediators of the information exchange. A set of logic models was then used to assess the role of measured phosphopeptides in the crosstalk. Our results show that the integration of the response to different stimuli requires complex interconnections between signaling pathways.
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Affiliation(s)
- Stefania Vaga
- Department of Biology, Institute of Molecular Systems Biology ETH Zürich, Zürich, Switzerland
| | - Marti Bernardo-Faura
- European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute (EBI), Cambridge, UK
| | - Thomas Cokelaer
- European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute (EBI), Cambridge, UK
| | - Alessio Maiolica
- Department of Biology, Institute of Molecular Systems Biology ETH Zürich, Zürich, Switzerland
| | - Christopher A Barnes
- Department of Biology, Institute of Molecular Systems Biology ETH Zürich, Zürich, Switzerland Department of Biology, Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Ludovic C Gillet
- Department of Biology, Institute of Molecular Systems Biology ETH Zürich, Zürich, Switzerland
| | - Björn Hegemann
- Department of Biology, Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Frank van Drogen
- Department of Biology, Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Hoda Sharifian
- Department of Biology, Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Edda Klipp
- Department of Biology, Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Matthias Peter
- Department of Biology, Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | - Julio Saez-Rodriguez
- European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute (EBI), Cambridge, UK
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology ETH Zürich, Zürich, Switzerland Faculty of Science, University of Zurich, Zurich, Switzerland
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Cdc42p-interacting protein Bem4p regulates the filamentous-growth mitogen-activated protein kinase pathway. Mol Cell Biol 2014; 35:417-36. [PMID: 25384973 DOI: 10.1128/mcb.00850-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ubiquitous Rho (Ras homology) GTPase Cdc42p can function in different settings to regulate cell polarity and cellular signaling. How Cdc42p and other proteins are directed to function in a particular context remains unclear. We show that the Cdc42p-interacting protein Bem4p regulates the mitogen-activated protein kinase (MAPK) pathway that controls filamentous growth in Saccharomyces cerevisiae. Bem4p controlled the filamentous-growth pathway but not other MAPK pathways (mating or high-osmolarity glycerol response [HOG]) that also require Cdc42p and other shared components. Bem4p associated with the plasma membrane (PM) protein, Sho1p, to regulate MAPK activity and cell polarization under nutrient-limiting conditions that favor filamentous growth. Bem4p also interacted with the major activator of Cdc42p, the guanine nucleotide exchange factor (GEF) Cdc24p, which we show also regulates the filamentous-growth pathway. Bem4p interacted with the pleckstrin homology (PH) domain of Cdc24p, which functions in an autoinhibitory capacity, and was required, along with other pathway regulators, to maintain Cdc24p at polarized sites during filamentous growth. Bem4p also interacted with the MAPK kinase kinase (MAPKKK) Ste11p. Thus, Bem4p is a new regulator of the filamentous-growth MAPK pathway and binds to general proteins, like Cdc42p and Ste11p, to promote a pathway-specific response.
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Identification and characterization of a Ste20-like kinase in Artemia and its role in the developmental regulation and resistance to environmental stress. PLoS One 2014; 9:e92234. [PMID: 24637947 PMCID: PMC3956927 DOI: 10.1371/journal.pone.0092234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/19/2014] [Indexed: 12/01/2022] Open
Abstract
Background To adapt to extreme environments, the crustacean Artemia has evolved two alternative reproductive pathways. During ovoviviparous (direct) development, nauplius larvae are produced. In contrast, Artemia females release encysted diapause embryos (cysts) via the oviparous pathway. To date, the cellular mechanisms that regulate stress resistance of Artemia remain largely unknown. Ste20-like kinase (SLK) participates in multiple biological processes, including stress responses, apoptosis, and cell cycle progression. Principal Finding We isolated and characterized a member of the SLK superfamily termed ArSLK from Artemia parthenogenetica. The ArSLK gene is transcribed throughout both ovoviviparous and oviparous development; however, the protein is located mainly in the nuclei of stress-resistant diapause cysts, unlike the nauplii and nauplius-destined embryos where it is cytoplasmic. Interestingly, exposure of nauplii to heat shock, acidic pH, and UV irradiation induced the translocation of ArSLK from cytoplasm to nucleus. This translocation was reversed following stress removal. Moreover, under physiologically-stressful conditions, the nauplius larvae produced by adults after gene knockdown of endogenous ArSLK by RNAi, lost the ability of free-swimming much earlier than those of control larvae from females injected with GFP dsRNA. Conclusions/Significance Taken together, this study demonstrated that trafficking of ArSLK between the cytoplasm and the nucleus participates in regulating the stress resistance of Artemia. Our findings may provide significant insight into the functions of members of the SLK superfamily.
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Tanaka K, Tatebayashi K, Nishimura A, Yamamoto K, Yang HY, Saito H. Yeast osmosensors Hkr1 and Msb2 activate the Hog1 MAPK cascade by different mechanisms. Sci Signal 2014; 7:ra21. [PMID: 24570489 DOI: 10.1126/scisignal.2004780] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To cope with environmental high osmolarity, the budding yeast Saccharomyces cerevisiae activates the mitogen-activated protein kinase (MAPK) Hog1, which controls an array of osmoadaptive responses. Two independent, but functionally redundant, osmosensing systems involving the transmembrane sensor histidine kinase Sln1 or the tetraspanning membrane protein Sho1 stimulate the Hog1 MAPK cascade. Furthermore, the Sho1 signaling branch itself also involves the two functionally redundant osmosensors Hkr1 and Msb2. However, any single osmosensor (Sln1, Hkr1, or Msb2) is sufficient for osmoadaptation. We found that the signaling mechanism by which Hkr1 or Msb2 stimulated the Hog1 cascade was specific to each osmosensor. Specifically, activation of Hog1 by Msb2 required the scaffold protein Bem1 and the actin cytoskeleton. Bem1 bound to the cytoplasmic domain of Msb2 and thus recruited the kinases Ste20 and Cla4 to the membrane, where either of them can activate the kinase Ste11. The cytoplasmic domain of Hkr1 also contributed to the activation of Ste11 by Ste20, but through a mechanism that involved neither Bem1 nor the actin cytoskeleton. Furthermore, we found a PXXP motif in Ste20 that specifically bound to the Sho1 SH3 (Src homology 3) domain. This interaction between Ste20 and Sho1 contributed to the activation of Hog1 by Hkr1, but not by Msb2. These differences between Hkr1 and Msb2 may enable differential regulation of these two proteins and provide a mechanism through Msb2 to connect regulation of the cytoskeleton with the response to osmotic stress.
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Affiliation(s)
- Keiichiro Tanaka
- 1Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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Li Y, Yi M, Zou X. Identification of the molecular mechanisms for cell-fate selection in budding yeast through mathematical modeling. Biophys J 2013; 104:2282-94. [PMID: 23708368 DOI: 10.1016/j.bpj.2013.03.057] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 01/30/2013] [Accepted: 03/05/2013] [Indexed: 11/19/2022] Open
Abstract
The specification and maintenance of cell fates is essential to the development of multicellular organisms. However, the precise molecular mechanisms in cell fate selection are, to our knowledge, poorly understood due to the complexity of multiple interconnected pathways. In this study, model-based quantitative analysis is used to explore how to maintain distinguished cell fates between cell-cycle commitment and mating arrest in budding yeast. We develop a full mathematical model of an interlinked regulatory network based on the available experimental data. By theoretically defining the Start transition point, the model is able to reproduce many experimental observations of the dynamical behaviors in wild-type cells as well as in Ste5-8A and Far1-S87A mutants. Furthermore, we demonstrate that a moderate ratio between Cln1/2→Far1 inhibition and Cln1/2→Ste5 inhibition is required to ensure a successful switch between different cell fates. We also show that the different ratios of the mutual Cln1/2 and Far1 inhibition determine the different cell fates. In addition, based on a new, definition of network entropy, we find that the Start point in wild-type cells coincides with the system's point of maximum entropy. This result indicates that Start is a transition point in the network entropy. Therefore, we theoretically explain the Start point from a network dynamics standpoint. Moreover, we analyze the biological bistablity of our model through bifurcation analysis. We find that the Cln1/2 and Cln3 production rates and the nonlinearity of SBF regulation on Cln1/2 production are potential determinants for irreversible entry into a new cell fate. Finally, the quantitative computations further reveal that high specificity and fidelity of the cell-cycle and mating pathways can guarantee specific cell-fate selection. These findings show that quantitative analysis and simulations with a mathematical model are useful tools for understanding the molecular mechanisms in cell-fate decisions.
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Affiliation(s)
- Yongkai Li
- School of Mathematics and Statistics, Wuhan University, Wuhan, P. R. China
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Randez-Gil F, Córcoles-Sáez I, Prieto JA. Genetic and Phenotypic Characteristics of Baker's Yeast: Relevance to Baking. Annu Rev Food Sci Technol 2013; 4:191-214. [DOI: 10.1146/annurev-food-030212-182609] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Francisca Randez-Gil
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
| | - Isaac Córcoles-Sáez
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
| | - José A. Prieto
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, 46980 Paterna, Valencia, Spain;
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Zhi H, Tang L, Xia Y, Zhang J. Ssk1p-independent activation of Ssk2p plays an important role in the osmotic stress response in Saccharomyces cerevisiae: alternative activation of Ssk2p in osmotic stress. PLoS One 2013; 8:e54867. [PMID: 23457455 PMCID: PMC3573049 DOI: 10.1371/journal.pone.0054867] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 12/19/2012] [Indexed: 12/05/2022] Open
Abstract
In Saccharomyces cerevisiae, external high osmolarity activates the HOG MAPK pathway, which controls various aspects of osmoregulation. MAPKKK Ssk2 is activated by Ssk1 in the SLN1 branch of the osmoregulatory HOG MAPK pathway under hyperosmotic stress. We observed that Ssk2 can be activated independent of Ssk1 upon osmotic shock by an unidentified mechanism. The domain for the Ssk1p-independent activation was identified to be located between the amino acids 177∼240. This region might be involved in the binding of an unknown regulator to Ssk2 which in turn activates Ssk2p without Ssk1p under hyperosmotic stress. The osmotic stress response through the Ssk1p-independent Ssk2p activation is strong, although its duration is short compared with the Ssk1p-dependent activation. The alternative Ssk2p activation is also important for the salt resistance.
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Affiliation(s)
- Hui Zhi
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Leihan Tang
- Department of Physics, and Center for Quantitative Systems Biology, Hong Kong Baptist University, Hong Kong, China
- * E-mail: (LT); (YX); (JZ)
| | - Yiji Xia
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
- * E-mail: (LT); (YX); (JZ)
| | - Jianhua Zhang
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail: (LT); (YX); (JZ)
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Abstract
An appropriate response and adaptation to hyperosmolarity, i.e., an external osmolarity that is higher than the physiological range, can be a matter of life or death for all cells. It is especially important for free-living organisms such as the yeast Saccharomyces cerevisiae. When exposed to hyperosmotic stress, the yeast initiates a complex adaptive program that includes temporary arrest of cell-cycle progression, adjustment of transcription and translation patterns, and the synthesis and retention of the compatible osmolyte glycerol. These adaptive responses are mostly governed by the high osmolarity glycerol (HOG) pathway, which is composed of membrane-associated osmosensors, an intracellular signaling pathway whose core is the Hog1 MAP kinase (MAPK) cascade, and cytoplasmic and nuclear effector functions. The entire pathway is conserved in diverse fungal species, while the Hog1 MAPK cascade is conserved even in higher eukaryotes including humans. This conservation is illustrated by the fact that the mammalian stress-responsive p38 MAPK can rescue the osmosensitivity of hog1Δ mutations in response to hyperosmotic challenge. As the HOG pathway is one of the best-understood eukaryotic signal transduction pathways, it is useful not only as a model for analysis of osmostress responses, but also as a model for mathematical analysis of signal transduction pathways. In this review, we have summarized the current understanding of both the upstream signaling mechanism and the downstream adaptive responses to hyperosmotic stress in yeast.
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Affiliation(s)
- Haruo Saito
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8638, Japan, and
| | - Francesc Posas
- Cell Signaling Unit, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, E-08003 Barcelona, Spain
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Fernandez-Piñar P, Alemán A, Sondek J, Dohlman HG, Molina M, Martín H. The Salmonella Typhimurium effector SteC inhibits Cdc42-mediated signaling through binding to the exchange factor Cdc24 in Saccharomyces cerevisiae. Mol Biol Cell 2012; 23:4430-43. [PMID: 23015760 PMCID: PMC3496616 DOI: 10.1091/mbc.e12-03-0243] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Expression of the Salmonella effector SteC in yeast leads to down-regulation of the mating and HOG pathways by Cdc42 inhibition. This is mediated by the SteC N-terminal domain through binding to the GEF Cdc24. SteC alters Cdc24 localization and also interacts with human GEF Vav1, suggesting that SteC could target Cdc42 function in host cells. Intracellular survival of Salmonella relies on the activity of proteins translocated into the host cell by type III secretion systems (T3SS). The protein kinase activity of the T3SS effector SteC is required for F-actin remodeling in host cells, although no SteC target has been identified so far. Here we show that expression of the N-terminal non-kinase domain of SteC down-regulates the mating and HOG pathways in Saccharomyces cerevisiae. Epistasis analyses using constitutively active components of these pathways indicate that SteC inhibits signaling at the level of the GTPase Cdc42. We demonstrate that SteC interacts through its N-terminal domain with the catalytic domain of Cdc24, the sole S. cerevisiae Cdc42 guanine nucleotide exchange factor (GEF). SteC also binds to the human Cdc24-like GEF protein Vav1. Moreover, expression of human Cdc42 suppresses growth inhibition caused by SteC. Of interest, the N-terminal SteC domain alters Cdc24 cellular localization, preventing its nuclear accumulation. These data reveal a novel functional domain within SteC, raising the possibility that this effector could also target GTPase function in mammalian cells. Our results also highlight the key role of the Cdc42 switch in yeast mating and HOG pathways and provide a new tool to study the functional consequences of Cdc24 localization.
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Affiliation(s)
- Pablo Fernandez-Piñar
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, and Instituto Ramón y Cajal de Investigaciones Sanitarias, 28040 Madrid, Spain
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A framework for mapping, visualisation and automatic model creation of signal-transduction networks. Mol Syst Biol 2012; 8:578. [PMID: 22531118 PMCID: PMC3361003 DOI: 10.1038/msb.2012.12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
An intuitive formalism for reconstructing cellular networks from empirical data is presented, and used to build a comprehensive yeast MAP kinase network. The accompanying rxncon software tool can convert networks to a range of standard graphical formats and mathematical models. ![]()
Network mapping at the granularity of empirical data that largely avoids combinatorial complexity Automatic visualisation and model generation with the rxncon open source software tool Visualisation in a range of formats, including all three SBGN formats, as well as contingency matrix or regulatory graph Comprehensive and completely references map of the yeast MAP kinase network in the rxncon format
Intracellular signalling systems are highly complex. This complexity makes handling, analysis and visualisation of available knowledge a major challenge in current signalling research. Here, we present a novel framework for mapping signal-transduction networks that avoids the combinatorial explosion by breaking down the network in reaction and contingency information. It provides two new visualisation methods and automatic export to mathematical models. We use this framework to compile the presently most comprehensive map of the yeast MAP kinase network. Our method improves previous strategies by combining (I) more concise mapping adapted to empirical data, (II) individual referencing for each piece of information, (III) visualisation without simplifications or added uncertainty, (IV) automatic visualisation in multiple formats, (V) automatic export to mathematical models and (VI) compatibility with established formats. The framework is supported by an open source software tool that facilitates integration of the three levels of network analysis: definition, visualisation and mathematical modelling. The framework is species independent and we expect that it will have wider impact in signalling research on any system.
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Regulation of vacuolar H+-ATPase activity by the Cdc42 effector Ste20 in Saccharomyces cerevisiae. EUKARYOTIC CELL 2012; 11:442-51. [PMID: 22327006 DOI: 10.1128/ec.05286-11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the budding yeast Saccharomyces cerevisiae, the Cdc42 effector Ste20 plays a crucial role in the regulation of filamentous growth, a response to nutrient limitation. Using the split-ubiquitin technique, we found that Ste20 forms a complex with Vma13, an important regulatory subunit of vacuolar H(+)-ATPase (V-ATPase). This protein-protein interaction was confirmed by a pulldown assay and coimmunoprecipitation. We also demonstrate that Ste20 associates with vacuolar membranes and that Ste20 stimulates V-ATPase activity in isolated vacuolar membranes. This activation requires Ste20 kinase activity and does not depend on increased assembly of the V1 and V0 sectors of the V-ATPase, which is a major regulatory mechanism. Furthermore, loss of V-ATPase activity leads to a strong increase in invasive growth, possibly because these cells fail to store and mobilize nutrients efficiently in the vacuole in the absence of the vacuolar proton gradient. In contrast to the wild type, which grows in rather small, isolated colonies on solid medium during filamentation, hyperinvasive vma mutants form much bigger aggregates in which a large number of cells are tightly clustered together. Genetic data suggest that Ste20 and the protein kinase A catalytic subunit Tpk2 are both activated in the vma13Δ strain. We propose that during filamentous growth, Ste20 stimulates V-ATPase activity. This would sustain nutrient mobilization from vacuolar stores, which is beneficial for filamentous growth.
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Boyce KJ, Andrianopoulos A. Ste20-related kinases: effectors of signaling and morphogenesis in fungi. Trends Microbiol 2011; 19:400-10. [PMID: 21640592 DOI: 10.1016/j.tim.2011.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/11/2011] [Accepted: 04/28/2011] [Indexed: 11/17/2022]
Abstract
The family of Ste20-related kinases is conserved from yeast to mammals and includes the p21 activated kinases (PAKs) and germinal centre kinases (GCKs). These kinases have been shown to be involved in signaling through mitogen activated protein kinase (MAPK) pathways and in morphogenesis through the regulation of cytokinesis and actin-dependent polarized growth. This review concentrates on the role of Ste20-related kinases in fungi where recent research has revealed roles for both PAKs and GCKs in the regulation of cytokinesis and in previously unidentified roles in promoting hyphal growth and differentiation of asexual development structures. In particular, the importance of PAKs during pathogenesis will be examined.
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Affiliation(s)
- Kylie J Boyce
- Department of Genetics, University of Melbourne, Victoria, Australia
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Doncic A, Falleur-Fettig M, Skotheim JM. Distinct interactions select and maintain a specific cell fate. Mol Cell 2011; 43:528-39. [PMID: 21855793 DOI: 10.1016/j.molcel.2011.06.025] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 04/23/2011] [Accepted: 06/07/2011] [Indexed: 11/16/2022]
Abstract
The ability to specify and maintain discrete cell fates is essential for development. However, the dynamics underlying selection and stability of distinct cell types remain poorly understood. Here, we provide a quantitative single-cell analysis of commitment dynamics during the mating-mitosis switch in budding yeast. Commitment to division corresponds precisely to activating the G1 cyclin positive feedback loop in competition with the cyclin inhibitor Far1. Cyclin-dependent phosphorylation and inhibition of the mating pathway scaffold Ste5 are required to ensure exclusive expression of the mitotic transcriptional program after cell cycle commitment. Failure to commit exclusively results in coexpression of both cell cycle and pheromone-induced genes, and a morphologically mixed inviable cell fate. Thus, specification and maintenance of a cellular state are performed by distinct interactions, which are likely a consequence of disparate reaction rates and may be a general feature of the interlinked regulatory networks responsible for selecting cell fates.
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Affiliation(s)
- Andreas Doncic
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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50
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Jones SK, Bennett RJ. Fungal mating pheromones: choreographing the dating game. Fungal Genet Biol 2011; 48:668-76. [PMID: 21496492 PMCID: PMC3100450 DOI: 10.1016/j.fgb.2011.04.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 02/23/2011] [Accepted: 04/05/2011] [Indexed: 01/11/2023]
Abstract
Pheromones are ubiquitous from bacteria to mammals - a testament to their importance in regulating inter-cellular communication. In fungal species, they play a critical role in choreographing interactions between mating partners during the program of sexual reproduction. Here, we describe how fungal pheromones are synthesized, their interactions with G protein-coupled receptors, and the signals propagated by this interaction, using Saccharomyces cerevisiae as a reference point. Divergence from this model system is compared amongst the ascomycetes and basidiomycetes, which reveals the wealth of information that has been gleaned from studying pheromone-driven processes across a wide spectrum of the fungal kingdom.
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Affiliation(s)
- Stephen K. Jones
- Graduate Program in Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - Richard J. Bennett
- Graduate Program in Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
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