1
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Neiman AM. Membrane and organelle rearrangement during ascospore formation in budding yeast. Microbiol Mol Biol Rev 2024; 88:e0001324. [PMID: 38899894 PMCID: PMC11426023 DOI: 10.1128/mmbr.00013-24] [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] [Indexed: 06/21/2024] Open
Abstract
SUMMARYIn ascomycete fungi, sexual spores, termed ascospores, are formed after meiosis. Ascospore formation is an unusual cell division in which daughter cells are created within the cytoplasm of the mother cell by de novo generation of membranes that encapsulate each of the haploid chromosome sets created by meiosis. This review describes the molecular events underlying the creation, expansion, and closure of these membranes in the budding yeast, Saccharomyces cerevisiae. Recent advances in our understanding of the regulation of gene expression and the dynamic behavior of different membrane-bound organelles during this process are detailed. While less is known about ascospore formation in other systems, comparison to the distantly related fission yeast suggests that the molecular events will be broadly similar throughout the ascomycetes.
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Affiliation(s)
- Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
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2
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Ottoz DSM, Tang LC, Dyatel AE, Jovanovic M, Berchowitz LE. Assembly and function of the amyloid-like translational repressor Rim4 is coupled with nutrient conditions. EMBO J 2023; 42:e113332. [PMID: 37921330 PMCID: PMC10690475 DOI: 10.15252/embj.2022113332] [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: 12/19/2022] [Revised: 09/20/2023] [Accepted: 09/25/2023] [Indexed: 11/04/2023] Open
Abstract
Amyloid-like protein assemblies have been associated with toxic phenotypes because of their repetitive and stable structure. However, evidence that cells exploit these structures to control function and activity of some proteins in response to stimuli has questioned this paradigm. How amyloid-like assembly can confer emergent functions and how cells couple assembly with environmental conditions remains unclear. Here, we study Rim4, an RNA-binding protein that forms translation-repressing assemblies during yeast meiosis. We demonstrate that in its assembled and repressive state, Rim4 binds RNA more efficiently than in its monomeric and idle state, revealing a causal connection between assembly and function. The Rim4-binding site location within the transcript dictates whether the assemblies can repress translation, underscoring the importance of the architecture of this RNA-protein structure for function. Rim4 assembly depends exclusively on its intrinsically disordered region and is prevented by the Ras/protein kinase A signaling pathway, which promotes growth and suppresses meiotic entry in yeast. Our results suggest a mechanism whereby cells couple a functional protein assembly with a stimulus to enforce a cell fate decision.
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Affiliation(s)
- Diana SM Ottoz
- Department of Genetics and Development, Hammer Health Sciences CenterColumbia University Irving Medical CenterNew YorkNYUSA
| | - Lauren C Tang
- Department of Biological SciencesColumbia UniversityNew YorkNYUSA
| | - Annie E Dyatel
- Department of Genetics and Development, Hammer Health Sciences CenterColumbia University Irving Medical CenterNew YorkNYUSA
| | - Marko Jovanovic
- Department of Biological SciencesColumbia UniversityNew YorkNYUSA
| | - Luke E Berchowitz
- Department of Genetics and Development, Hammer Health Sciences CenterColumbia University Irving Medical CenterNew YorkNYUSA
- Taub Institute for Research on Alzheimer's and the Aging BrainNew YorkNYUSA
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3
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Rojas J, Oz T, Jonak K, Lyzak O, Massaad V, Biriuk O, Zachariae W. Spo13/MEIKIN ensures a Two-Division meiosis by preventing the activation of APC/C Ama1 at meiosis I. EMBO J 2023; 42:e114288. [PMID: 37728253 PMCID: PMC10577557 DOI: 10.15252/embj.2023114288] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 09/03/2023] [Accepted: 09/04/2023] [Indexed: 09/21/2023] Open
Abstract
Genome haploidization at meiosis depends on two consecutive nuclear divisions, which are controlled by an oscillatory system consisting of Cdk1-cyclin B and the APC/C bound to the Cdc20 activator. How the oscillator generates exactly two divisions has been unclear. We have studied this question in yeast where exit from meiosis involves accumulation of the APC/C activator Ama1 at meiosis II. We show that inactivation of the meiosis I-specific protein Spo13/MEIKIN results in a single-division meiosis due to premature activation of APC/CAma1 . In the wild type, Spo13 bound to the polo-like kinase Cdc5 prevents Ama1 synthesis at meiosis I by stabilizing the translational repressor Rim4. In addition, Cdc5-Spo13 inhibits the activity of Ama1 by converting the B-type cyclin Clb1 from a substrate to an inhibitor of Ama1. Cdc20-dependent degradation of Spo13 at anaphase I unleashes a feedback loop that increases Ama1's synthesis and activity, leading to irreversible exit from meiosis at the second division. Thus, by repressing the exit machinery at meiosis I, Cdc5-Spo13 ensures that cells undergo two divisions to produce haploid gametes.
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Affiliation(s)
- Julie Rojas
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
Laboratory of GeneticsUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Tugce Oz
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Katarzyna Jonak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
- Present address:
Institute of Biochemistry and BiophysicsPolish Academy of SciencesWarsawPoland
| | - Oleksii Lyzak
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Vinal Massaad
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Olha Biriuk
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
| | - Wolfgang Zachariae
- Laboratory of Chromosome BiologyMax Planck Institute of BiochemistryMartinsriedGermany
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4
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Cao C, Wang K, Wang Y, Liu TB, Rivera A, Xue C. Ubiquitin proteolysis of a CDK-related kinase regulates titan cell formation and virulence in the fungal pathogen Cryptococcus neoformans. Nat Commun 2022; 13:6397. [PMID: 36302775 PMCID: PMC9613880 DOI: 10.1038/s41467-022-34151-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 10/17/2022] [Indexed: 12/25/2022] Open
Abstract
Fungal pathogens often undergo morphological switches, including cell size changes, to adapt to the host environment and cause disease. The pathogenic yeast Cryptococcus neoformans forms so-called 'titan cells' during infection. Titan cells are large, polyploid, display alterations in cell wall and capsule, and are more resistant to phagocytosis and various types of stress. Titan cell formation is regulated by the cAMP/PKA signal pathway, which is stimulated by the protein Gpa1. Here, we show that Gpa1 is activated through phosphorylation by a CDK-related kinase (Crk1), which is targeted for degradation by an E3 ubiquitin ligase (Fbp1). Strains overexpressing CRK1 or an allele lacking a PEST domain exhibit increased production of titan cells similarly to the fbp1∆ mutant. Conversely, CRK1 deletion results in reduced titan cell production, indicating that Crk1 stimulates titan cell formation. Crk1 phosphorylates Gpa1, which then localizes to the plasma membrane and activates the cAMP/PKA signal pathway to induce cell enlargement. Furthermore, titan cell-overproducing strains trigger increased Th1 and Th17 cytokine production in CD4+ T cells and show attenuated virulence in a mouse model of systemic cryptococcosis. Overall, our study provides insights into the regulation of titan cell formation and fungal virulence.
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Affiliation(s)
- Chengjun Cao
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Keyi Wang
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Yina Wang
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Tong-Bao Liu
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
- Medical Research Institute, Southwest University, Chongqing, 400715, China
| | - Amariliz Rivera
- Center for Immunity and Inflammation, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Chaoyang Xue
- Public Health Research Institute, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
- Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ, 08901, USA.
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5
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Xiao J, Zhang Y, Yang K, Tang Y, Wei L, Liu E, Liang Z. Protein kinase Ime2 is associated with mycelial growth, conidiation, osmoregulation, and pathogenicity in Fusarium oxysporum. Arch Microbiol 2022; 204:455. [PMID: 35788908 PMCID: PMC9252944 DOI: 10.1007/s00203-022-02964-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/10/2022] [Indexed: 11/30/2022]
Abstract
Fusarium oxysporum f.sp. niveum is one of the most serious diseases impairing watermelon yield and quality. Inducer of meiosis 2 (Ime2) is the founding member of a family of serine/threonine protein kinases and plays important roles in yeasts and other filamentous fungi. In this study, we analyzed the functions of FoIme2, the ortholog of Saccharomyces cerevisiae Ime2 in F. oxysporum f.sp. niveum. The FoIme2-deleted mutants exhibited obvious morphological abnormalities, including slower vegetative growth, more branches in the edge hyphae and a reduction in conidia production. Compared to the wild type, the mutants were hypersensitive to the osmotic stressor NaCl but were more insensitive to the membrane stressor SDS. The deletion of FoIme2 also caused a reduction in pathogenicity. Transcriptional analysis revealed that FoIme2 acts downstream of FoOpy2 which is an upstream sensor of the MAPK kinase cascade. These results indicate that FoIme2 is important in the development and pathogenicity of F. oxysporum, and provide new insight for the analysis of the pathogenic mechanism of F. oxysporum.
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Affiliation(s)
- Jiling Xiao
- College of Plant Protection, Hunan Agricultural University, Changsha, 410125, China.,Hunan Agricultural Biotechnology Research Institute, Changsha, 410125, China
| | - Yi Zhang
- Hunan Rice Research Institute, Changsha, 410125, China
| | - Ke Yang
- Hunan Agricultural Biotechnology Research Institute, Changsha, 410125, China
| | - Yanying Tang
- Hunan Plant Protection Institute, Changsha, 410125, China
| | - Lin Wei
- Hunan Plant Protection Institute, Changsha, 410125, China
| | - Erming Liu
- College of Plant Protection, Hunan Agricultural University, Changsha, 410125, China.
| | - Zhihuai Liang
- Hunan Agricultural Biotechnology Research Institute, Changsha, 410125, China.
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6
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Oz T, Mengoli V, Rojas J, Jonak K, Braun M, Zagoriy I, Zachariae W. The Spo13/Meikin pathway confines the onset of gamete differentiation to meiosis II in yeast. EMBO J 2022; 41:e109446. [PMID: 35023198 PMCID: PMC8844990 DOI: 10.15252/embj.2021109446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/06/2021] [Accepted: 12/20/2021] [Indexed: 11/09/2022] Open
Abstract
Sexual reproduction requires genome haploidization by the two divisions of meiosis and a differentiation program to generate gametes. Here, we have investigated how sporulation, the yeast equivalent of gamete differentiation, is coordinated with progression through meiosis. Spore differentiation is initiated at metaphase II when a membrane-nucleating structure, called the meiotic plaque, is assembled at the centrosome. While all components of this structure accumulate already at entry into meiosis I, they cannot assemble because centrosomes are occupied by Spc72, the receptor of the γ-tubulin complex. Spc72 is removed from centrosomes by a pathway that depends on the polo-like kinase Cdc5 and the meiosis-specific kinase Ime2, which is unleashed by the degradation of Spo13/Meikin upon activation of the anaphase-promoting complex at anaphase I. Meiotic plaques are finally assembled upon reactivation of Cdk1 at entry into metaphase II. This unblocking-activation mechanism ensures that only single-copy genomes are packaged into spores and might serve as a paradigm for the regulation of other meiosis II-specific processes.
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Affiliation(s)
- Tugce Oz
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Valentina Mengoli
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Julie Rojas
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Katarzyna Jonak
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Marianne Braun
- Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Ievgeniia Zagoriy
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Wolfgang Zachariae
- Laboratory of Chromosome Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
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7
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Isc10, an Inhibitor That Links the Anaphase-Promoting Complex to a Meiosis-Specific Mitogen-Activated Protein Kinase. Mol Cell Biol 2020; 40:MCB.00097-20. [PMID: 32423992 DOI: 10.1128/mcb.00097-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/13/2020] [Indexed: 11/20/2022] Open
Abstract
Smk1 is a meiosis-specific mitogen-activated protein kinase (MAPK) in yeast that controls spore differentiation. It is activated by a MAPK binding protein, Ssp2, upon completion of the meiotic divisions. The activation of Smk1 by Ssp2 is positively regulated by a meiosis-specific coactivator of the anaphase promoting complex (APC/C) E3 ubiquitin ligase, Ama1. Here, we identify Isc10 as an inhibitor that links APC/CAma1 to Smk1 activation. Isc10 and Smk1 form an inhibited complex during meiosis I (MI). Ssp2 is produced later in the program, and it forms a ternary complex with Isc10 and Smk1 during MII that is poised for activation. Upon completion of MII, Isc10 is ubiquitylated and degraded in an AMA1-dependent manner, thereby triggering the activation of Smk1 by Ssp2. Mutations that caused Ssp2 to be produced before MII, or isc10Δ mutations, modestly reduced the efficiency of spore differentiation whereas spores were nearly absent in the double mutant. These findings define a pathway that couples spore differentiation to the G0-like phase of the cell cycle.
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8
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Xie M, Bai N, Yang J, Jiang K, Zhou D, Zhao Y, Li D, Niu X, Zhang KQ, Yang J. Protein Kinase Ime2 Is Required for Mycelial Growth, Conidiation, Osmoregulation, and Pathogenicity in Nematode-Trapping Fungus Arthrobotrys oligospora. Front Microbiol 2020; 10:3065. [PMID: 31993040 PMCID: PMC6971104 DOI: 10.3389/fmicb.2019.03065] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 12/18/2019] [Indexed: 11/26/2022] Open
Abstract
Inducer of meiosis 2 (Ime2), a protein kinase that has been identified in diverse fungal species, functions in the regulation of various cellular processes, such as ascospore formation, pseudohyphal growth, and sexual reproduction. In this study, AoIme2, an ortholog of Saccharomyces cerevisiae Ime2, was characterized in the nematode-trapping fungus Arthrobotrys oligospora. Disruption of the gene Aoime2 caused defective growth, with slower mycelial growth in ΔAoime2 mutants than the wild type (WT) strain, and in the mutants, the number of hyphal septa in mycelia was higher and the number of cell nuclei in mycelia and conidia was considerably lower than in the WT strain. The conidial yields of the ΔAoime2 mutants were decreased by ∼33% relative to the WT strain, and the transcription of several sporulation-related genes, including abaA, fluG, rodA, aspB, velB, and vosA, was markedly downregulated during the conidiation stage. The ΔAoime2 mutants were highly sensitive to the osmotic stressors NaCl and sorbitol, and the cell wall of partial hyphae in the mutants was deformed. Further examination revealed that the cell wall of the traps produced by ΔAoime2 mutants became loose, and that the electron-dense bodies in trap cells were also few than in the WT strain. Moreover, Aoime2 disruption caused a reduction in trap formation and serine-protease production, and most hyphal traps produced by ΔAoime2 mutants did not form an intact hyphal loop; consequently, substantially fewer nematodes were captured by the mutants than by the WT strain. In summary, an Ime2-MAPK is identified here for the first time from a nematode-trapping fungus, and the kinase is shown to be involved in the regulation of mycelial growth and development, conidiation, osmolarity, and pathogenicity in A. oligospora.
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Affiliation(s)
- Meihua Xie
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China.,Department of Chemistry and Life Science, Chuxiong Normal University, Chuxiong, China
| | - Na Bai
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Jiangliu Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Kexin Jiang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Duanxu Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Yining Zhao
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Dongni Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Xuemei Niu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China.,School of Life Sciences, Yunnan University, Kunming, China.,Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
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9
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Hollingsworth NM, Gaglione R. The meiotic-specific Mek1 kinase in budding yeast regulates interhomolog recombination and coordinates meiotic progression with double-strand break repair. Curr Genet 2019; 65:631-641. [PMID: 30671596 DOI: 10.1007/s00294-019-00937-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 11/29/2022]
Abstract
Recombination, along with sister chromatid cohesion, is used during meiosis to physically connect homologous chromosomes so that they can be segregated properly at the first meiotic division. Recombination is initiated by the introduction of programmed double strand breaks (DSBs) into the genome, a subset of which is processed into crossovers. In budding yeast, the regulation of meiotic DSB repair is controlled by a meiosis-specific kinase called Mek1. Mek1 kinase activity promotes recombination between homologs, rather than sister chromatids, as well as the processing of recombination intermediates along a pathway that results in synapsis of homologous chromosomes and the distribution of crossovers throughout the genome. In addition, Mek1 kinase activity provides a readout for the number of DSBs in the cell as part of the meiotic recombination checkpoint. This checkpoint delays entry into the first meiotic division until DSBs have been repaired by inhibiting the activity of the meiosis-specific transcription factor Ndt80, a site-specific DNA binding protein that activates transcription of over 300 target genes. Recent work has shown that Mek1 binds to Ndt80 and phosphorylates it on multiple sites, including the DNA binding domain, thereby preventing Ndt80 from activating transcription. As DSBs are repaired, Mek1 is removed from chromosomes and its activity decreases. Loss of the inhibitory Mek1 phosphates and phosphorylation of Ndt80 by the meiosis-specific kinase, Ime2, promote Ndt80 activity such that Ndt80 transcribes its own gene in a positive feedback loop, as well as genes required for the completion of recombination and entry into the meiotic divisions. Mek1 is therefore the key regulator of meiotic recombination in yeast.
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Affiliation(s)
- Nancy M Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA.
| | - Robert Gaglione
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA
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10
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Chen X, Gaglione R, Leong T, Bednor L, de los Santos T, Luk E, Airola M, Hollingsworth NM. Mek1 coordinates meiotic progression with DNA break repair by directly phosphorylating and inhibiting the yeast pachytene exit regulator Ndt80. PLoS Genet 2018; 14:e1007832. [PMID: 30496175 PMCID: PMC6289461 DOI: 10.1371/journal.pgen.1007832] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/11/2018] [Accepted: 11/13/2018] [Indexed: 02/02/2023] Open
Abstract
Meiotic recombination plays a critical role in sexual reproduction by creating crossovers between homologous chromosomes. These crossovers, along with sister chromatid cohesion, connect homologs to enable proper segregation at Meiosis I. Recombination is initiated by programmed double strand breaks (DSBs) at particular regions of the genome. The meiotic recombination checkpoint uses meiosis-specific modifications to the DSB-induced DNA damage response to provide time to convert these breaks into interhomolog crossovers by delaying entry into Meiosis I until the DSBs have been repaired. The meiosis-specific kinase, Mek1, is a key regulator of meiotic recombination pathway choice, as well as being required for the meiotic recombination checkpoint. The major target of this checkpoint is the meiosis-specific transcription factor, Ndt80, which is essential to express genes necessary for completion of recombination and meiotic progression. The molecular mechanism by which cells monitor meiotic DSB repair to allow entry into Meiosis I with unbroken chromosomes was unknown. Using genetic and biochemical approaches, this work demonstrates that in the presence of DSBs, activated Mek1 binds to Ndt80 and phosphorylates the transcription factor, thus inhibiting DNA binding and preventing Ndt80's function as a transcriptional activator. Repair of DSBs by recombination reduces Mek1 activity, resulting in removal of the inhibitory Mek1 phosphates. Phosphorylation of Ndt80 by the meiosis-specific kinase, Ime2, then results in fully activated Ndt80. Ndt80 upregulates transcription of its own gene, as well as target genes, resulting in prophase exit and progression through meiosis.
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Affiliation(s)
- Xiangyu Chen
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Robert Gaglione
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Trevor Leong
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Lauren Bednor
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Teresa de los Santos
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Ed Luk
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Michael Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Nancy M. Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
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11
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Sequestration of mRNAs Modulates the Timing of Translation during Meiosis in Budding Yeast. Mol Cell Biol 2015. [PMID: 26217015 DOI: 10.1128/mcb.00189-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Starvation of diploid cells of the budding yeast Saccharomyces cerevisiae induces them to enter meiosis and differentiate into haploid spores. During meiosis, the precise timing of gene expression is controlled at the level of transcription, and also translation. If cells are returned to rich medium after they have committed to meiosis, the transcript levels of most meiotically upregulated genes decrease rapidly. However, for a subset of transcripts whose translation is delayed until the end of meiosis II, termed protected transcripts, the transcript levels remain stable even after nutrients are reintroduced. The Ime2-Rim4 regulatory circuit controls both the delayed translation and the stability of protected transcripts. These protected mRNAs localize in discrete foci, which are not seen for transcripts of genes with different translational timing and are regulated by Ime2. These results suggest that Ime2 and Rim4 broadly regulate translational delay but that additional factors, such as mRNA localization, modulate this delay to tune the timing of gene expression to developmental transitions during sporulation.
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12
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Berchowitz LE, Gajadhar AS, van Werven FJ, De Rosa AA, Samoylova ML, Brar GA, Xu Y, Xiao C, Futcher B, Weissman JS, White FM, Amon A. A developmentally regulated translational control pathway establishes the meiotic chromosome segregation pattern. Genes Dev 2013; 27:2147-63. [PMID: 24115771 PMCID: PMC3850098 DOI: 10.1101/gad.224253.113] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/03/2013] [Indexed: 11/25/2022]
Abstract
Production of haploid gametes from diploid progenitor cells is mediated by a specialized cell division, meiosis, where two divisions, meiosis I and II, follow a single S phase. Errors in progression from meiosis I to meiosis II lead to aneuploid and polyploid gametes, but the regulatory mechanisms controlling this transition are poorly understood. Here, we demonstrate that the conserved kinase Ime2 regulates the timing and order of the meiotic divisions by controlling translation. Ime2 coordinates translational activation of a cluster of genes at the meiosis I-meiosis II transition, including the critical determinant of the meiotic chromosome segregation pattern CLB3. We further show that Ime2 mediates translational control through the meiosis-specific RNA-binding protein Rim4. Rim4 inhibits translation of CLB3 during meiosis I by interacting with the 5' untranslated region (UTR) of CLB3. At the onset of meiosis II, Ime2 kinase activity rises and triggers a decrease in Rim4 protein levels, thereby alleviating translational repression. Our results elucidate a novel developmentally regulated translational control pathway that establishes the meiotic chromosome segregation pattern.
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Affiliation(s)
- Luke E. Berchowitz
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute
| | - Aaron S. Gajadhar
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Folkert J. van Werven
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute
| | - Alexandra A. De Rosa
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute
| | - Mariya L. Samoylova
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute
| | - Gloria A. Brar
- Howard Hughes Medical Institute
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA
- California Institute for Quantitative Biosciences, San Francisco, California 94158, USA
| | - Yifeng Xu
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Che Xiao
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Bruce Futcher
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Jonathan S. Weissman
- Howard Hughes Medical Institute
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94158, USA
- California Institute for Quantitative Biosciences, San Francisco, California 94158, USA
| | - Forest M. White
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Angelika Amon
- Koch Institute for Integrative Cancer Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Howard Hughes Medical Institute
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13
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Carreras-Villaseñor N, Esquivel-Naranjo EU, Villalobos-Escobedo JM, Abreu-Goodger C, Herrera-Estrella A. The RNAi machinery regulates growth and development in the filamentous fungusTrichoderma atroviride. Mol Microbiol 2013; 89:96-112. [DOI: 10.1111/mmi.12261] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Nohemi Carreras-Villaseñor
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Edgardo U. Esquivel-Naranjo
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - J. Manuel Villalobos-Escobedo
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Cei Abreu-Goodger
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
| | - Alfredo Herrera-Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad; Cinvestav Sede Irapuato; Km 9.6 Libramiento Norte Carretera Irapuato-León; 36821; Irapuato; Gto.; Mexico
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14
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Winter E. The Sum1/Ndt80 transcriptional switch and commitment to meiosis in Saccharomyces cerevisiae. Microbiol Mol Biol Rev 2012; 76:1-15. [PMID: 22390969 PMCID: PMC3294429 DOI: 10.1128/mmbr.05010-11] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cells encounter numerous signals during the development of an organism that induce division, differentiation, and apoptosis. These signals need to be present for defined intervals in order to induce stable changes in the cellular phenotype. The point after which an inducing signal is no longer needed for completion of a differentiation program can be termed the "commitment point." Meiotic development in the yeast Saccharomyces cerevisiae (sporulation) provides a model system to study commitment. Similar to differentiation programs in multicellular organisms, the sporulation program in yeast is regulated by a transcriptional cascade that produces early, middle, and late sets of sporulation-specific transcripts. Although critical meiosis-specific events occur as early genes are expressed, commitment does not take place until middle genes are induced. Middle promoters are activated by the Ndt80 transcription factor, which is produced and activated shortly before most middle genes are expressed. In this article, I discuss the connection between Ndt80 and meiotic commitment. A transcriptional regulatory pathway makes NDT80 transcription contingent on the prior expression of early genes. Once Ndt80 is produced, the recombination (pachytene) checkpoint prevents activation of the Ndt80 protein. Upon activation, Ndt80 triggers a positive autoregulatory loop that leads to the induction of genes that promote exit from prophase, the meiotic divisions, and spore formation. The pathway is controlled by multiple feed-forward loops that give switch-like properties to the commitment transition. The conservation of regulatory components of the meiotic commitment pathway and the recently reported ability of Ndt80 to increase replicative life span are discussed.
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Affiliation(s)
- Edward Winter
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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15
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Abstract
In response to nitrogen starvation in the presence of a poor carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and package the haploid nuclei produced in meiosis into spores. The formation of spores requires an unusual cell division event in which daughter cells are formed within the cytoplasm of the mother cell. This process involves the de novo generation of two different cellular structures: novel membrane compartments within the cell cytoplasm that give rise to the spore plasma membrane and an extensive spore wall that protects the spore from environmental insults. This article summarizes what is known about the molecular mechanisms controlling spore assembly with particular attention to how constitutive cellular functions are modified to create novel behaviors during this developmental process. Key regulatory points on the sporulation pathway are also discussed as well as the possible role of sporulation in the natural ecology of S. cerevisiae.
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16
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Abstract
Ime2 of the budding yeast Saccharomyces cerevisiae belongs to a family of conserved protein kinases displaying sequence similarities to both cyclin-dependent kinases and mitogen-activated protein kinases. Ime2 has a pivotal role for meiosis and sporulation. The involvement of this protein kinase in the regulation of various key events in meiosis, such as the initiation of DNA replication, the expression of meiosis-specific genes and the passage through the two consecutive rounds of nuclear divisions has been characterized in detail. More than 20 years after the identification of the IME2 gene, a recent report has provided the first evidence for a function of this gene outside of meiosis, which is the regulation of pseudohyphal growth. In the last few years, Ime2-related protein kinases from various fungal species were studied. Remarkably, these homologues are not generally required for meiosis, but instead have other specific tasks. In filamentous ascomycete species, Ime2 homologues are involved in the inhibition of fruiting body formation in response to environmental signals. In the pathogenic basidiomycetes Ustilago maydis and Cryptococcus neoformans, members of this kinase family apparently have primary roles in regulating mating. Thus, Ime2-related kinases exhibit an amazing variety in controlling sexual developmental programs in fungi.
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Affiliation(s)
- Stefan Irniger
- Institute of Microbiology and Genetics, Georg August University, Grisebachstr. 8, D-37077 Göttingen, Germany.
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17
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Ime1 and Ime2 are required for pseudohyphal growth of Saccharomyces cerevisiae on nonfermentable carbon sources. Mol Cell Biol 2010; 30:5514-30. [PMID: 20876298 DOI: 10.1128/mcb.00390-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudohyphal growth and meiosis are two differentiation responses to nitrogen starvation of diploid Saccharomyces cerevisiae. Nitrogen starvation in the presence of fermentable carbon sources is thought to induce pseudohyphal growth, whereas nitrogen and sugar starvation induces meiosis. In contrast to the genetic background routinely used to study pseudohyphal growth (Σ1278b), nonfermentable carbon sources stimulate pseudohyphal growth in the efficiently sporulating strain SK1. Pseudohyphal SK1 cells can exit pseudohyphal growth to complete meiosis. Two stimulators of meiosis, Ime1 and Ime2, are required for pseudohyphal growth of SK1 cells in the presence of nonfermentable carbon sources. Epistasis analysis suggests that Ime1 and Ime2 act in the same order in pseudohyphal growth as in meiosis. The different behaviors of strains SK1 and Σ1278b are in part attributable to differences in cyclic AMP (cAMP) signaling. In contrast to Σ1278b cells, hyperactivation of cAMP signaling using constitutively active Ras2(G19V) inhibited pseudohyphal growth in SK1 cells. Our data identify the SK1 genetic background as an alternative genetic background for the study of pseudohyphal growth and suggest an overlap between signaling pathways controlling pseudohyphal growth and meiosis. Based on these findings, we propose to include exit from pseudohyphal growth and entry into meiosis in the life cycle of S. cerevisiae.
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Abstract
N6-Methyladenosine (m6A) is a modified base present in the mRNA of all higher eukaryotes and in Saccharomyces cerevisiae, where there is an increase in m6A levels during sporulation. The methyltransferase, Ime4, is responsible for this modification and has a role in the initiation of meiosis. However, neither the function, nor the extent of distribution of this nucleotide modification is established. We demonstrate that in S. cerevisiae, substantial levels of internal adenosine methylation are present in the GpA context in mRNA from sporulating cells, which is consistent with the preferred methylation consensus of higher eukaryotes. Based upon our quantification data, every second transcript could contain one m6A during meiosis. As methylation is distributed across all mRNA size ranges, it is likely that m6A is not limited to a small population of messages. We developed a new antibody based method for identifying m6A containing messages, and using this method the transcripts of three key, early regulators of meiosis, IME1, IME2 and IME4 itself, were identified as being methylated. The position of m6A in IME2 was narrowed down to a region in the 3′-end. Methylation of these and other targets suggests mechanisms by which IME4 could control developmental choices leading to meiosis.
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Affiliation(s)
- Zsuzsanna Bodi
- School of Biosciences, Plant Sciences Division, University of Nottingham, Sutton Bonington, Loughborough LE12 5RD, UK
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Nolting N, Bernhards Y, Pöggeler S. SmATG7 is required for viability in the homothallic ascomycete Sordaria macrospora. Fungal Genet Biol 2009; 46:531-42. [DOI: 10.1016/j.fgb.2009.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 03/14/2009] [Accepted: 03/30/2009] [Indexed: 10/20/2022]
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20
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Bayram Ö, Sari F, Braus GH, Irniger S. The protein kinase ImeB is required for light-mediated inhibition of sexual development and for mycotoxin production inAspergillus nidulans. Mol Microbiol 2009; 71:1278-95. [DOI: 10.1111/j.1365-2958.2009.06606.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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The Ras/cAMP pathway and the CDK-like kinase Ime2 regulate the MAPK Smk1 and spore morphogenesis in Saccharomyces cerevisiae. Genetics 2008; 181:511-23. [PMID: 19087957 DOI: 10.1534/genetics.108.098434] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Meiotic development (sporulation) in the yeast Saccharomyces cerevisiae is induced by nutritional deprivation. Smk1 is a meiosis-specific MAP kinase homolog that controls spore morphogenesis after the meiotic divisions have taken place. In this study, recessive mutants that suppress the sporulation defect of a smk1-2 temperature-sensitive hypomorph were isolated. The suppressors are partial function alleles of CDC25 and CYR1, which encode the Ras GDP/GTP exchange factor and adenyl cyclase, respectively, and MDS3, which encodes a kelch-domain protein previously implicated in Ras/cAMP signaling. Deletion of PMD1, which encodes a Mds3 paralog, also suppressed the smk1-2 phenotype, and a mds3-Delta pmd1-Delta double mutant was a more potent suppressor than either single mutant. The mds3-Delta, pmd1-Delta, and mds3-Delta pmd1-Delta mutants also exhibited mitotic Ras/cAMP phenotypes in the same rank order. The effect of Ras/cAMP pathway mutations on the smk1-2 phenotype required the presence of low levels of glucose. Ime2 is a meiosis-specific CDK-like kinase that is inhibited by low levels of glucose via its carboxy-terminal regulatory domain. IME2-DeltaC241, which removes the carboxy-terminal domain of Ime2, exacerbated the smk1-2 spore formation phenotype and prevented cyr1 mutations from suppressing smk1-2. Inhibition of Ime2 in meiotic cells shortly after Smk1 is expressed revealed that Ime2 promotes phosphorylation of Smk1's activation loop. These findings demonstrate that nutrients can negatively regulate Smk1 through the Ras/cAMP pathway and that Ime2 is a key activator of Smk1 signaling.
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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