1
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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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2
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Single-particle imaging of stress-promoters induction reveals the interplay between MAPK signaling, chromatin and transcription factors. Nat Commun 2020; 11:3171. [PMID: 32576833 PMCID: PMC7311541 DOI: 10.1038/s41467-020-16943-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 06/02/2020] [Indexed: 01/25/2023] Open
Abstract
Precise regulation of gene expression in response to environmental changes is crucial for cell survival, adaptation and proliferation. In eukaryotic cells, extracellular signal integration is often carried out by Mitogen-Activated Protein Kinases (MAPK). Despite a robust MAPK signaling activity, downstream gene expression can display a great variability between single cells. Using a live mRNA reporter, here we monitor the dynamics of transcription in Saccharomyces cerevisiae upon hyper-osmotic shock. We find that the transient activity of the MAPK Hog1 opens a temporal window where stress-response genes can be activated. We show that the first minutes of Hog1 activity are essential to control the activation of a promoter. Chromatin repression on a locus slows down this transition and contributes to the variability in gene expression, while binding of transcription factors increases the level of transcription. However, soon after Hog1 activity peaks, negative regulators promote chromatin closure of the locus and transcription progressively stops.
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3
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Modular and tunable biological feedback control using a de novo protein switch. Nature 2019; 572:265-269. [PMID: 31341280 DOI: 10.1038/s41586-019-1425-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/11/2019] [Indexed: 11/08/2022]
Abstract
De novo-designed proteins1-3 hold great promise as building blocks for synthetic circuits, and can complement the use of engineered variants of natural proteins4-7. One such designer protein-degronLOCKR, which is based on 'latching orthogonal cage-key proteins' (LOCKR) technology8-is a switch that degrades a protein of interest in vivo upon induction by a genetically encoded small peptide. Here we leverage the plug-and-play nature of degronLOCKR to implement feedback control of endogenous signalling pathways and synthetic gene circuits. We first generate synthetic negative and positive feedback in the yeast mating pathway by fusing degronLOCKR to endogenous signalling molecules, illustrating the ease with which this strategy can be used to rewire complex endogenous pathways. We next evaluate feedback control mediated by degronLOCKR on a synthetic gene circuit9, to quantify the feedback capabilities and operational range of the feedback control circuit. The designed nature of degronLOCKR proteins enables simple and rational modifications to tune feedback behaviour in both the synthetic circuit and the mating pathway. The ability to engineer feedback control into living cells represents an important milestone in achieving the full potential of synthetic biology10,11,12. More broadly, this work demonstrates the large and untapped potential of de novo design of proteins for generating tools that implement complex synthetic functionalities in cells for biotechnological and therapeutic applications.
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4
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Shellhammer JP, Pomeroy AE, Li Y, Dujmusic L, Elston TC, Hao N, Dohlman HG. Quantitative analysis of the yeast pheromone pathway. Yeast 2019; 36:495-518. [PMID: 31022772 DOI: 10.1002/yea.3395] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/10/2019] [Accepted: 04/16/2019] [Indexed: 01/04/2023] Open
Abstract
The pheromone response pathway of the yeast Saccharomyces cerevisiae is a well-established model for the study of G proteins and mitogen-activated protein kinase (MAPK) cascades. Our longstanding ability to combine sophisticated genetic approaches with established functional assays has provided a thorough understanding of signalling mechanisms and regulation. In this report, we compare new and established methods used to quantify pheromone-dependent MAPK phosphorylation, transcriptional induction, mating morphogenesis, and gradient tracking. These include both single-cell and population-based assays of activity. We describe several technical advances, provide example data for benchmark mutants, highlight important differences between newer and established methodologies, and compare the advantages and disadvantages of each as applied to the yeast model. Quantitative measurements of pathway activity have been used to develop mathematical models and reveal new regulatory mechanisms in yeast. It is our expectation that experimental and computational approaches developed in yeast may eventually be adapted to human systems biology and pharmacology.
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Affiliation(s)
- James P Shellhammer
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Amy E Pomeroy
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yang Li
- Division of Biological Sciences, University of California San Diego, San Diego, CA, 92093, USA
| | - Lorena Dujmusic
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Timothy C Elston
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Nan Hao
- Division of Biological Sciences, University of California San Diego, San Diego, CA, 92093, USA
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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5
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Serrano A, Illgen J, Brandt U, Thieme N, Letz A, Lichius A, Read ND, Fleißner A. Spatio-temporal MAPK dynamics mediate cell behavior coordination during fungal somatic cell fusion. J Cell Sci 2018; 131:jcs.213462. [PMID: 29592970 DOI: 10.1242/jcs.213462] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/20/2018] [Indexed: 01/17/2023] Open
Abstract
Mitogen-activated protein kinases (MAPKs) are conserved regulators of proliferation, differentiation and adaptation in eukaryotic cells. Their activity often involves changes in their subcellular localization, indicating an important role for these spatio-temporal dynamics in signal transmission. A striking model illustrating these dynamics is somatic cell fusion in Neurospora crassa Germinating spores of this fungus rapidly alternate between signal sending and receiving, thereby establishing a cell-cell dialog, which involves the alternating membrane recruitment of the MAPK MAK-2 in both fusion partners. Here, we show that the dynamic translocation of MAK-2 is essential for coordinating the behavior of the fusion partners before physical contact. The activation and function of the kinase strongly correlate with its subcellular localization, indicating a crucial contribution of the MAPK dynamics in establishing regulatory feedback loops, which establish the oscillatory signaling mode. In addition, we provide evidence that MAK-2 not only contributes to cell-cell communication, but also mediates cell-cell fusion. The MAK-2 dynamics significantly differ between these two processes, suggesting a role for the MAPK in switching of the cellular program between communication and fusion.
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Affiliation(s)
- Antonio Serrano
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Julia Illgen
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Ulrike Brandt
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Nils Thieme
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Anja Letz
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Alexander Lichius
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Nick D Read
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9NT, UK
| | - André Fleißner
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstraße 7, 38106 Braunschweig, Germany
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6
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Day AM, Herrero-de-Dios CM, MacCallum DM, Brown AJP, Quinn J. Stress-induced nuclear accumulation is dispensable for Hog1-dependent gene expression and virulence in a fungal pathogen. Sci Rep 2017; 7:14340. [PMID: 29085028 PMCID: PMC5662626 DOI: 10.1038/s41598-017-14756-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/09/2017] [Indexed: 11/11/2022] Open
Abstract
Stress-activated protein kinase (SAPK) pathways are evolutionarily conserved eukaryotic signalling modules that are essential for the virulence of human pathogenic fungi. The Hog1 SAPK in Candida albicans is robustly phosphorylated in response to a number of host-imposed stresses, and is essential for virulence. The current dogma is that stress-induced phosphorylation activates the SAPK, and promotes its nuclear accumulation that is necessary for the expression of SAPK-dependent stress-protective genes. Here we challenge this dogma. C. albicans strains were constructed in which Hog1 was either tethered to the plasma membrane or constitutively nuclear. Strikingly, tethering Hog1 to the plasma membrane did not abrogate stress resistance or stress-induced gene expression. Furthermore, preventing the nuclear accumulation of Hog1 had no impact on C. albicans virulence in two distinct models of systemic infection. However, tethering Hog1 to the plasma membrane did impact on signal fidelity, and on the magnitude and kinetics of the stress-induced phosphorylation of this SAPK. Taken together, these findings challenge the dogma that nuclear accumulation of SAPKs is a pre-requisite for SAPK-dependent gene expression, and reveal that stress-induced nuclear accumulation of Hog1 is dispensable for the virulence of a major human fungal pathogen.
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Affiliation(s)
- Alison M Day
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Carmen M Herrero-de-Dios
- MRC Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, AB25 2ZD, UK
| | - Donna M MacCallum
- MRC Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, AB25 2ZD, UK
| | - Alistair J P Brown
- MRC Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, AB25 2ZD, UK
| | - Janet Quinn
- Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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7
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Li G, Zhang X, Tian H, Choi YE, Tao WA, Xu JR. MST50 is involved in multiple MAP kinase signaling pathways in Magnaporthe oryzae. Environ Microbiol 2017; 19:1959-1974. [PMID: 28244240 DOI: 10.1111/1462-2920.13710] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 02/17/2017] [Accepted: 02/19/2017] [Indexed: 12/31/2022]
Abstract
Appressorium formation plays a critical role in Magnaporthe oryzae. Mst50 is an adapter protein of the Mst11-Mst7-Pmk1 cascade that is essential for appressorium formation. To further characterize its functions, affinity purification was used to identify Mst50-interacting proteins (MIPs) in this study. Two of the MIPs are Mst11 and Mst7 that are known to interact with Mst50 for Pmk1 activation. Surprisingly, two other MIPs are Mck1 and Mkk2 that are the upstream kinases of the Mps1 pathway. Domain deletion analysis showed that the sterile alpha-motif of Mst50 but not the Ras-association domain was important for its interaction with Mck1 and responses to cell wall and oxidative stresses. The mst50 mutant was reduced in Mps1 activation under stress conditions. MIP11 encodes a RACK1 protein that also interacted with Mck1. Deletion of MIP11 resulted in defects in cell wall integrity, Mps1 phosphorylation and plant infection. Furthermore, Mst50 interacted with histidine kinase Hik1, and the mst50 mutant was reduced in Osm1 phosphorylation. These results indicated that Mst50 is involved in all three MAPK pathways in M. oryzae although its functions differ in each pathway. Several MIPs are conserved hypothetical proteins and may be involved in responses to various signals and crosstalk among signaling pathways.
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Affiliation(s)
- Guotian Li
- Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Xue Zhang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Huan Tian
- Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yoon-E Choi
- Division of Environmental Science and Ecological Engineering, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - W Andy Tao
- Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA
| | - Jin-Rong Xu
- Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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8
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Pelet S. Nuclear relocation of Kss1 contributes to the specificity of the mating response. Sci Rep 2017; 7:43636. [PMID: 28262771 PMCID: PMC5337980 DOI: 10.1038/srep43636] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/25/2017] [Indexed: 01/14/2023] Open
Abstract
Mitogen Activated Protein Kinases (MAPK) play a central role in transducing extra-cellular signals into defined biological responses. These enzymes, conserved in all eukaryotes, exert their function via the phosphorylation of numerous substrates located throughout the cell and by inducing a complex transcriptional program. The partitioning of their activity between the cytoplasm and the nucleus is thus central to their function. Budding yeast serves as a powerful system to understand the regulation of these fundamental biological phenomena. Under vegetative growth, the MAPK Kss1 is enriched in the nucleus of the cells. Stimulation with mating pheromone results in a rapid relocation of the protein in the cytoplasm. Activity of either Fus3 or Kss1 in the mating pathway is sufficient to drive this change in location by disassembling the complex formed between Kss1, Ste12 and Dig1. Artificial enrichment of the MAPK Kss1 in the nucleus in presence of mating pheromone alters the transcriptional response of the cells and induces a cell-cycle arrest in absence of Fus3 and Far1.
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Affiliation(s)
- Serge Pelet
- Department of Fundamental Microbiology University of Lausanne Lausanne, Switzerland
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9
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Lu R, Drubin DG. Selection and stabilization of endocytic sites by Ede1, a yeast functional homologue of human Eps15. Mol Biol Cell 2017; 28:567-575. [PMID: 28057762 PMCID: PMC5328616 DOI: 10.1091/mbc.e16-06-0391] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/09/2016] [Accepted: 12/29/2016] [Indexed: 12/19/2022] Open
Abstract
During clathrin-mediated endocytosis (CME), endocytic-site maturation can be divided into two stages corresponding to the arrival of the early and late proteins at the plasma membrane. The early proteins are required to capture cargo and position the late machinery, which includes proteins involved in actin assembly and membrane scission. However, the mechanism by which early-arriving proteins select and stabilize endocytic sites is not known. Ede1, one of the earliest proteins recruited to endocytic sites, facilitates site initiation and stabilization. Deletion of EDE1 results in fewer CME initiations and defects in the timing of vesicle maturation. Here we made truncation mutants of Ede1 to better understand how different domains contribute to its recruitment to CME sites, site selection, and site maturation. We found that the minimal domains required for efficient Ede1 localization at CME sites are the third EH domain, the proline-rich region, and the coiled-coil region. We also found that many strains expressing ede1 truncations could support a normal rate of site initiation but still had defects in site-maturation timing, indicating separation of Ede1 functions. When expressed in yeast, human Eps15 localized to the plasma membrane, where it recruited late-phase CME proteins and supported productive endocytosis, identifying it as an Ede1 functional homologue.
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Affiliation(s)
- Rebecca Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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10
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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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11
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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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12
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Cell fusion in Neurospora crassa. Curr Opin Microbiol 2015; 28:53-9. [DOI: 10.1016/j.mib.2015.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 12/22/2022]
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13
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Furukawa K, Hohmann S. Synthetic biology: lessons from engineering yeast MAPK signalling pathways. Mol Microbiol 2013; 88:5-19. [PMID: 23461595 DOI: 10.1111/mmi.12174] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2013] [Indexed: 02/04/2023]
Abstract
All living cells respond to external stimuli and execute specific physiological responses through signal transduction pathways. Understanding the mechanisms controlling signalling pathways is important for diagnosing and treating diseases and for reprogramming cells with desired functions. Although many of the signalling components in the budding yeast Saccharomyces cerevisiae have been identified by genetic studies, many features concerning the dynamic control of pathway activity, cross-talk, cell-to-cell variability or robustness against perturbation are still incompletely understood. Comparing the behaviour of engineered and natural signalling pathways offers insight complementary to that achievable with standard genetic and molecular studies. Here, we review studies that aim at a deeper understanding of signalling design principles and generation of novel signalling properties by engineering the yeast mitogen-activated protein kinase (MAPK) pathways. The underlying approaches can be applied to other organisms including mammalian cells and offer opportunities for building synthetic pathways and functionalities useful in medicine and biotechnology.
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Affiliation(s)
- Kentaro Furukawa
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 40530 Gothenburg, Sweden.
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14
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Formation of subnuclear foci is a unique spatial behavior of mating MAPKs during hyperosmotic stress. Cell Rep 2013; 3:328-34. [PMID: 23416049 DOI: 10.1016/j.celrep.2013.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/09/2012] [Accepted: 01/16/2013] [Indexed: 11/22/2022] Open
Abstract
The assembly of signaling components and transcription factors in ordered subcellular structures is increasingly implicated as an important regulatory strategy for modulating the activity of cellular pathways. Here, we document the inducible formation of subnuclear foci formed by two mitogen-activated protein kinases (MAPKs) in Saccharomyces cerevisiae upon hyperosmotic stress. Specifically, we demonstrate that activation of the hyperosmotic stress response pathway induces the mating pathway MAPK Fus3 and the filamentation pathway MAPK Kss1 to form foci in the nucleus that are organized by their shared downstream transcription factor Ste12. Foci formation of colocalized Ste12, Fus3, and Kss1 requires the kinase activity of the hyperosmotic response MAPK Hog1 and correlates with attenuated signaling in the mating pathway. Conversely, activation of the mating pathway prevents foci formation upon subsequent hyperosmotic stress. These results suggest that Hog1-mediated spatial localization of Fus3 and Ste12 into subnuclear foci could contribute to uncoupling the pheromone and osmolarity pathways, which share signaling components, under high-osmolarity conditions.
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15
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Patterson JC, Klimenko ES, Thorner J. Single-cell analysis reveals that insulation maintains signaling specificity between two yeast MAPK pathways with common components. Sci Signal 2010; 3:ra75. [PMID: 20959523 DOI: 10.1126/scisignal.2001275] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Eukaryotic cells use multiple mitogen-activated protein kinase (MAPK) cascades to evoke appropriate responses to external stimuli. In Saccharomyces cerevisiae, the MAPK Fus3 is activated by pheromone-binding heterotrimeric guanosine triphosphate-binding protein (G protein)-coupled receptors to promote mating, whereas the MAPK Hog1 is activated by hyperosmotic stress to elicit the high-osmolarity glycerol (HOG) response. Although these MAPK pathways share several upstream components, exposure to either pheromone or osmolyte alone triggers only the appropriate response. We used fluorescence localization- and transcription-specific reporters to assess activation of these pathways in individual cells on the minute and hour time scale, respectively. Dual activation of these two MAPK pathways occurred over a broad range of stimulant concentrations and temporal regimes in wild-type cells subjected to costimulation. Thus, signaling specificity is achieved through an "insulation" mechanism, not a "cross-inhibition" mechanism. Furthermore, we showed that there was a critical period during which Hog1 activity had to occur for proper insulation of the HOG pathway.
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Affiliation(s)
- Jesse C Patterson
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA
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