1
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Harrell MA, Liu Z, Campbell BF, Chinsen O, Hong T, Das M. Arp2/3-dependent endocytosis ensures Cdc42 oscillations by removing Pak1-mediated negative feedback. J Cell Biol 2024; 223:e202311139. [PMID: 39012625 PMCID: PMC11259211 DOI: 10.1083/jcb.202311139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/10/2024] [Accepted: 07/01/2024] [Indexed: 07/17/2024] Open
Abstract
The GTPase Cdc42 regulates polarized growth in most eukaryotes. In the bipolar yeast Schizosaccharomyces pombe, Cdc42 activation cycles periodically at sites of polarized growth. These periodic cycles are caused by alternating positive feedback and time-delayed negative feedback loops. At each polarized end, negative feedback is established when active Cdc42 recruits the Pak1 kinase to prevent further Cdc42 activation. It is unclear how Cdc42 activation returns to each end after Pak1-dependent negative feedback. We find that disrupting branched actin-mediated endocytosis disables Cdc42 reactivation at the cell ends. Using experimental and mathematical approaches, we show that endocytosis-dependent Pak1 removal from the cell ends allows the Cdc42 activator Scd1 to return to that end to enable reactivation of Cdc42. Moreover, we show that Pak1 elicits its own removal via activation of endocytosis. These findings provide a deeper insight into the self-organization of Cdc42 regulation and reveal previously unknown feedback with endocytosis in the establishment of cell polarity.
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Affiliation(s)
| | - Ziyi Liu
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | | | - Olivia Chinsen
- Biology Department, Boston College, Chestnut Hill, MA, USA
| | - Tian Hong
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Maitreyi Das
- Biology Department, Boston College, Chestnut Hill, MA, USA
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2
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Li H, Zhu J, Li Z, Xu P, Ma L, Zou Y, Qu S, Wu X. Contrasting effects of NADPH oxidases on the fungal hyphae growth and immune responses in Pleurotus ostreatus. Front Microbiol 2024; 15:1387643. [PMID: 38962136 PMCID: PMC11220167 DOI: 10.3389/fmicb.2024.1387643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 06/03/2024] [Indexed: 07/05/2024] Open
Abstract
Pleurotus ostreatus is one of the most consumed mushroom species, as it serves as a high-quality food, favors a rich secondary metabolism, and has remarkable adaptability to the environment and predators. In this study, we investigated the function of two key reactive oxygen species producing enzyme NADPH oxidase (PoNoxA and PoNoxB) in P. ostreatus hyphae growth, metabolite production, signaling pathway activation, and immune responses to different stresses. Characterization of the Nox mutants showed that PoNoxB played an important role in the hyphal formation of the multicellular structure, while PoNoxA regulated apical dominance. The ability of P. ostreatus to tolerate a series of abiotic stress conditions (e.g., osmotic, oxidative, membrane, and cell-wall stresses) and mechanical damage repair was enhanced with PoNoxA over-expression. PoNoxB had a greater responsibility in regulating the polysaccharide composition of the cell wall and methyl jasmonate and gibberellin GA1 biosynthesis, and improved mushroom resistance against Tyrophagus putrescentiae. Moreover, mutants were involved in the jasmonate and GA signaling pathway, and toxic protein defense metabolite production. Our findings shed light on how the oyster mushroom senses stress signals and responds to adverse environments by the complex regulators of Noxs.
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Affiliation(s)
- Huiping Li
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Jiachun Zhu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Zihao Li
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ping Xu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Lin Ma
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Yajie Zou
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shaoxuan Qu
- Institute of Vegetable Crops, Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, China
| | - Xiaoqin Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu, China
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3
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Qin K, Yu M, Fan J, Wang H, Zhao P, Zhao G, Zeng W, Chen C, Wang Y, Wang A, Schwartz Z, Hong J, Song L, Wagstaff W, Haydon RC, Luu HH, Ho SH, Strelzow J, Reid RR, He TC, Shi LL. Canonical and noncanonical Wnt signaling: Multilayered mediators, signaling mechanisms and major signaling crosstalk. Genes Dis 2024; 11:103-134. [PMID: 37588235 PMCID: PMC10425814 DOI: 10.1016/j.gendis.2023.01.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/01/2022] [Accepted: 01/29/2023] [Indexed: 08/18/2023] Open
Abstract
Wnt signaling plays a major role in regulating cell proliferation and differentiation. The Wnt ligands are a family of 19 secreted glycoproteins that mediate their signaling effects via binding to Frizzled receptors and LRP5/6 coreceptors and transducing the signal either through β-catenin in the canonical pathway or through a series of other proteins in the noncanonical pathway. Many of the individual components of both canonical and noncanonical Wnt signaling have additional functions throughout the body, establishing the complex interplay between Wnt signaling and other signaling pathways. This crosstalk between Wnt signaling and other pathways gives Wnt signaling a vital role in many cellular and organ processes. Dysregulation of this system has been implicated in many diseases affecting a wide array of organ systems, including cancer and embryological defects, and can even cause embryonic lethality. The complexity of this system and its interacting proteins have made Wnt signaling a target for many therapeutic treatments. However, both stimulatory and inhibitory treatments come with potential risks that need to be addressed. This review synthesized much of the current knowledge on the Wnt signaling pathway, beginning with the history of Wnt signaling. It thoroughly described the different variants of Wnt signaling, including canonical, noncanonical Wnt/PCP, and the noncanonical Wnt/Ca2+ pathway. Further description involved each of its components and their involvement in other cellular processes. Finally, this review explained the various other pathways and processes that crosstalk with Wnt signaling.
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Affiliation(s)
- Kevin Qin
- Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Michael Yu
- Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jiaming Fan
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Ministry of Education Key Laboratory of Diagnostic Medicine, and Department of Clinical Biochemistry, The School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Hongwei Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Piao Zhao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Departments of Orthopaedic Surgery and Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Guozhi Zhao
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Departments of Orthopaedic Surgery and Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Wei Zeng
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Department of Interventional Neurology, The First Dongguan Affiliated Hospital, Guangdong Medical University, Dongguan, Guangdong 523475, China
| | - Connie Chen
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Yonghui Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Department of Clinical Laboratory Medicine, Shanghai Jiaotong University School of Medicine, Shanghai 200000, China
| | - Annie Wang
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Department of Surgery Section of Plastic Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Zander Schwartz
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- School of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Jeffrey Hong
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Lily Song
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - William Wagstaff
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Rex C. Haydon
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Hue H. Luu
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Sherwin H. Ho
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Jason Strelzow
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Russell R. Reid
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Department of Surgery Section of Plastic Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Tong-Chuan He
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
- Laboratory of Craniofacial Biology and Development, Department of Surgery Section of Plastic Surgery, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Lewis L. Shi
- Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
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4
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Harrell M, Liu Z, Campbell BF, Chinsen O, Hong T, Das M. The Arp2/3 complex promotes periodic removal of Pak1-mediated negative feedback to facilitate anticorrelated Cdc42 oscillations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566261. [PMID: 38106068 PMCID: PMC10723479 DOI: 10.1101/2023.11.08.566261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The conserved GTPase Cdc42 is a major regulator of polarized growth in most eukaryotes. Cdc42 periodically cycles between active and inactive states at sites of polarized growth. These periodic cycles are caused by positive feedback and time-delayed negative feedback loops. In the bipolar yeast S. pombe, both growing ends must regulate Cdc42 activity. At each cell end, Cdc42 activity recruits the Pak1 kinase which prevents further Cdc42 activation thus establishing negative feedback. It is unclear how Cdc42 activation returns to the end after Pak1-dependent negative feedback. Using genetic and chemical perturbations, we find that disrupting branched actin-mediated endocytosis disables Cdc42 reactivation at the cell ends. With our experimental data and mathematical models, we show that endocytosis-dependent Pak1 removal from the cell ends allows the Cdc42 activator Scd1 to return to that end to enable reactivation of Cdc42. Moreover, we show that Pak1 elicits its own removal via activation of endocytosis. In agreement with these observations, our model and experimental data show that in each oscillatory cycle, Cdc42 activation increases followed by an increase in Pak1 recruitment at that end. These findings provide a deeper insight into the self-organization of Cdc42 regulation and reveal previously unknown feedback with endocytosis in the establishment of cell polarity.
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Affiliation(s)
- Marcus Harrell
- Biology Department, Boston College, Chestnut Hill, MA, 02467
| | - Ziyi Liu
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, TN, 37916
| | | | - Olivia Chinsen
- Biology Department, Boston College, Chestnut Hill, MA, 02467
| | - Tian Hong
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, TN, 37916
| | - Maitreyi Das
- Biology Department, Boston College, Chestnut Hill, MA, 02467
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5
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Kingma E, Diepeveen ET, Iñigo de la Cruz L, Laan L. Pleiotropy drives evolutionary repair of the responsiveness of polarized cell growth to environmental cues. Front Microbiol 2023; 14:1076570. [PMID: 37520345 PMCID: PMC10382278 DOI: 10.3389/fmicb.2023.1076570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 06/19/2023] [Indexed: 08/01/2023] Open
Abstract
The ability of cells to translate different extracellular cues into different intracellular responses is vital for their survival in unpredictable environments. In Saccharomyces cerevisiae, cell polarity is modulated in response to environmental signals which allows cells to adopt varying morphologies in different external conditions. The responsiveness of cell polarity to extracellular cues depends on the integration of the molecular network that regulates polarity establishment with networks that signal environmental changes. The coupling of molecular networks often leads to pleiotropic interactions that can make it difficult to determine whether the ability to respond to external signals emerges as an evolutionary response to environmental challenges or as a result of pleiotropic interactions between traits. Here, we study how the propensity of the polarity network of S. cerevisiae to evolve toward a state that is responsive to extracellular cues depends on the complexity of the environment. We show that the deletion of two genes, BEM3 and NRP1, disrupts the ability of the polarity network to respond to cues that signal the onset of the diauxic shift. By combining experimental evolution with whole-genome sequencing, we find that the restoration of the responsiveness to these cues correlates with mutations in genes involved in the sphingolipid synthesis pathway and that these mutations frequently settle in evolving populations irrespective of the complexity of the selective environment. We conclude that pleiotropic interactions make a significant contribution to the evolution of networks that are responsive to extracellular cues.
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6
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de Cubas L, Mallor J, Herrera-Fernández V, Ayté J, Vicente R, Hidalgo E. Expression of the H2O2 Biosensor roGFP-Tpx1.C160S in Fission and Budding Yeasts and Jurkat Cells to Compare Intracellular H2O2 Levels, Transmembrane Gradients, and Response to Metals. Antioxidants (Basel) 2023; 12:antiox12030706. [PMID: 36978953 PMCID: PMC10045392 DOI: 10.3390/antiox12030706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/01/2023] [Accepted: 03/07/2023] [Indexed: 03/16/2023] Open
Abstract
Intracellular hydrogen peroxide (H2O2) levels can oscillate from low, physiological concentrations, to intermediate, signaling ones, and can participate in toxic reactions when overcoming certain thresholds. Fluorescent protein-based reporters to measure intracellular H2O2 have been developed in recent decades. In particular, the redox-sensitive green fluorescent protein (roGFP)-based proteins fused to peroxiredoxins are among the most sensitive H2O2 biosensors. Using fission yeast as a model system, we recently demonstrated that the gradient of extracellular-to-intracellular peroxides through the plasma membrane is around 300:1, and that the concentration of physiological H2O2 is in the low nanomolar range. Here, we have expressed the very sensitive probe roGFP2-Tpx1.C169S in two other model systems, budding yeast and human Jurkat cells. As in fission yeast, the biosensor is ~40–50% oxidized in these cell types, suggesting similar peroxide steady-state levels. Furthermore, probe oxidation upon the addition of extracellular peroxides is also quantitatively similar, suggesting comparable plasma membrane H2O2 gradients. Finally, as a proof of concept, we have applied different concentrations of zinc to all three model systems and have detected probe oxidation, demonstrating that an excess of this metal can cause fluctuations of peroxides, which are moderate in yeasts and severe in mammalian cells. We conclude that the principles governing H2O2 fluxes are very similar in different model organisms.
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Affiliation(s)
- Laura de Cubas
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Jorge Mallor
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Víctor Herrera-Fernández
- Laboratory of Molecular Physiology, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Rubén Vicente
- Laboratory of Molecular Physiology, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/ Doctor Aiguader 88, 08003 Barcelona, Spain
- Correspondence: ; Tel.: +34-93-316-0848; Fax: +34-93-316-0901
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7
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Salat-Canela C, Pérez P, Ayté J, Hidalgo E. Stress-induced cell depolarization through the MAP kinase-Cdc42 axis. Trends Cell Biol 2023; 33:124-137. [PMID: 35773059 DOI: 10.1016/j.tcb.2022.06.004] [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] [Received: 04/12/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 01/25/2023]
Abstract
General stress responses, which sense environmental or endogenous signals, aim at promoting cell survival and fitness during adverse conditions. In eukaryotes, mitogen-activated protein (MAP) kinase-driven cascades trigger a shift in the cell's gene expression program as a cellular adaptation to stress. Here, we review another aspect of activated MAP kinase cascades reported in fission yeast: the transient inhibition of cell polarity in response to oxidative stress. The phosphorylation by a stress-activated MAP kinase of regulators of the GTPase cell division cycle 42 (Cdc42) causes a transient inhibition of polarized cell growth. The formation of growth sites depends on limiting and essential polarity components. We summarize here some processes in which inhibition of Cdc42 may be a general mechanism to regulate polarized growth also under physiological conditions.
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Affiliation(s)
- Clàudia Salat-Canela
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Dr. Aiguader 88, 08003, Barcelona, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, Universidad de Salamanca, 37007 Salamanca, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Dr. Aiguader 88, 08003, Barcelona, Spain.
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, C/Dr. Aiguader 88, 08003, Barcelona, Spain.
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Hu Y, Luo Y, Yin D, Zhao L, Wang Y, Yao R, Zhang P, Wu X, Li M, Hidalgo E, Huang Y. Schizosaccharomyces pombe MAP kinase Sty1 promotes survival of Δppr10 cells with defective mitochondrial protein synthesis. Int J Biochem Cell Biol 2022; 152:106308. [PMID: 36174923 DOI: 10.1016/j.biocel.2022.106308] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/09/2022] [Accepted: 09/23/2022] [Indexed: 11/19/2022]
Abstract
Deletion of the Schizosaccharomyces pombe pentatricopeptide repeat gene ppr10 severely impairs mitochondrial translation, resulting in defective oxidative phosphorylation (OXPHOS). ppr10 deletion also induces iron starvation response, resulting in increased reactive oxygen species (ROS) production and reduced viability under fermentative conditions. S. pombe has two principal stress-response pathways, which are mediated by the mitogen-activated protein kinase Sty1 and the basic leucine zipper transcription factor Pap1, respectively. In this study, we examined the roles of Sty1 and Pap1 in the cellular response to the mitochondrial translation defect caused by ppr10 deletion. We found that ppr10 deletion resulted in two waves of stress protein activation. The early response occurred in exponential phase and resulted in the expression of a subset of stress proteins including Gst2 and Obr1. The upregulation of some of these stress proteins in Δppr10 cells in early response is dependent on the basal nuclear levels of Sty1 or Pap1. The late response occurred in early stationary phase and coincided with the stable localization of Sty1 and Pap1 in the nucleus, presumably resulting in persistent activation of a large set of stress proteins. Deletion of sty1 in Δppr10 cells caused severe defects in cell division and growth, and further impaired cell viability. Deletion of the mitochondrial superoxide dismutase gene sod2 whose expression is controlled by Sty1 severely inhibited the growth of Δppr10 cells. Overexpression of sod2 improves the viability of Δppr10 cells. Our results support an important role for Sty1 in counteracting stress induced by ppr10 deletion under fermentative growth conditions.
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Affiliation(s)
- Yue Hu
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Ying Luo
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Dan Yin
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Lan Zhao
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Yirong Wang
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Rui Yao
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Pan Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Xiaoyu Wu
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Minjie Li
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Elena Hidalgo
- Departament de Ciènces Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Ying Huang
- Jiangsu Key Laboratory for Microbes and Functional Genetics, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
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9
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A stress-blinded Atf1 can fully assemble heterochromatin in a RNAi-independent minimal mat locus but impairs directionality of mat2/3 switching. iScience 2022; 25:104820. [PMID: 35992058 PMCID: PMC9389250 DOI: 10.1016/j.isci.2022.104820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/03/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022] Open
Abstract
The MAP kinase Sty1 phosphorylates and activates the transcription factor Atf1 in response to several stress conditions, which then shifts from a transcriptional repressor to an activator. Atf1 also participates in heterochromatin assembly at the mat locus, in combination with the RNA interference (RNAi) machinery. Here, we study the role of signal-dependent phosphorylation of Atf1 in heterochromatin establishment at mat, using different Atf1 phospho mutants. Although a hypo-phosphorylation Atf1 mutant, Atf1.10M, mediates heterochromatin assembly, the phosphomimic Atf1.10D is unable to maintain silencing. In a minimal mat locus, lacking the RNAi-recruiting cis elements and displaying intermediate silencing, Atf1.10M restores full heterochromatin and silencing. However, evolution experiments with this stress-blinded Atf1.10M show that it is unable to facilitate switching between the donor site mat3 and mat1. We propose that the unphosphorylated, inactive Atf1 contributes to proper heterochromatin assembly by recruiting repressive complexes, but its stress-dependent phosphorylation is required for recombination/switching to occur. The phosphorylation domain of Atf1 TF is required for heterochromatin assembly at mat Hypo-phosphorylated Atf1.10M mediates silencing by recruiting repressive complexes Stress-dependent phosphorylation of Atf1 is required for recombination and switching Atf1.10M is a heterochromatin assembly factor but impairs mat2/3 switching
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