scholarly journals The S. pombe CDK5 ortholog Pef1 regulates sexual differentiation through control of the TORC1 pathway and autophagy

2020 ◽  
Vol 133 (17) ◽  
pp. jcs247817
Author(s):  
Shinya Matsuda ◽  
Ushio Kikkawa ◽  
Haruka Uda ◽  
Akio Nakashima
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Differentiation ◽  
Environmental Changes ◽  
Nitrogen Starvation ◽  
General Strategy ◽  
Positive Regulation ◽  
Starvation Response ◽  
Double Deletion ◽  
Early Phases

ABSTRACTIn Schizosaccharomyces pombe, a general strategy for survival in response to environmental changes is sexual differentiation, which is triggered by TORC1 inactivation. However, mechanisms of TORC1 regulation in fission yeast remain poorly understood. In this study, we found that Pef1, which is an ortholog of mammalian CDK5, regulates the initiation of sexual differentiation through positive regulation of TORC1 activity. Conversely, deletion of pef1 leads to activation of autophagy and subsequent excessive TORC1 reactivation during the early phases of the nitrogen starvation response. This excessive TORC1 reactivation results in the silencing of the Ste11-Mei2 pathway and mating defects. Additionally, we found that pef1 genetically interacts with tsc1 and tsc2 for TORC1 regulation, and physically interacts with three cyclins, Clg1, Pas1 and Psl1. The double deletion of clg1 and pas1 promotes activation of autophagy and TORC1 during nitrogen starvation, similar to what is seen in pef1Δ cells. Overall, our work suggests that Pef1–Clg1 and Pef1–Pas1 complexes regulate initiation of sexual differentiation through control of the TSC–TORC1 pathway and autophagy.

scholarly journals Autophagy-deficient Schizosaccharomyces pombe mutants undergo partial sporulation during nitrogen starvation

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3816-3826 ◽  
Author(s):  
Hiroyuki Mukaiyama ◽  
Shiro Kajiwara ◽  
Akira Hosomi ◽  
Yuko Giga-Hama ◽  
Naotaka Tanaka ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nitrogen Source ◽  
Environmental Changes ◽  
Nitrogen Starvation ◽  
Nitrogen Sources ◽  
Vacuole Fusion ◽  
Sporulation Process

Autophagy is triggered when organisms sense radical environmental changes, including nutritional starvation. During autophagy, cytoplasmic components, including organelles, are enclosed within autophagosomes and are degraded upon lysosome–vacuole fusion. In this study, we show that processing of GFP-tagged Atg8 can serve as a marker for autophagy in the fission yeast Schizosaccharomyces pombe. Using this marker, 13 Atg homologues were also found to be required for autophagy in fission yeast. In budding yeast, autophagy-deficient mutants are known to be sterile, whereas in fission yeast we found that up to 30 % of autophagy-defective cells with amino acid auxotrophy were able to recover sporulation when an excess of required amino acids was supplied. Furthermore, we found that approximately 15 % of the autophagy-defective cells were also able to sporulate when a prototrophic strain was subjected to nitrogen starvation, which suggested that fission yeast may store sufficient intracellular nitrogen to allow partial sporulation under nitrogen-limiting conditions, although the majority of the nitrogen source is supplied by autophagy. Monitoring of the sporulation process revealed that the process was blocked non-specifically at various stages in the atg1Δ and atg12Δ mutants, possibly due to a shortage of amino acids. Taking advantage of this partial sporulation ability of fission yeast, we sought evidence for the existence of a recycling system for nitrogen sources during starvation.

fhl1 gene of the fission yeast regulates transcription of meiotic genes and nitrogen starvation response, downstream of the TORC1 pathway

2016 ◽  
Vol 63 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Emese Pataki ◽  
Ronit Weisman ◽  
Matthias Sipiczki ◽  
Ida Miklos
Keyword(s):  
Fission Yeast ◽  
Nitrogen Starvation ◽  
Starvation Response

Bob1, a Gim5/MM-1/Pfd5 homolog, interacts with the MAP kinase kinase Byr1 to regulate sexual differentiation in the fission yeast, Schizosaccharomyces pombe

2001 ◽  
Vol 67 (4-5) ◽  
pp. 98-106 ◽  
Author(s):  
Jenny Henkel ◽  
Hongyan Du ◽  
Peirong Yang ◽  
Yibing Qyang ◽  
Sanjay Kansra ◽  
...  
Keyword(s):  
Map Kinase ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Differentiation ◽  
Map Kinase Kinase

Analysis of the Schizosaccharomyces pombe cyclin puc1: evidence for a role in cell cycle exit

1994 ◽  
Vol 107 (3) ◽  
pp. 601-613 ◽  
Author(s):  
S.L. Forsburg ◽  
P. Nurse
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Sexual Development ◽  
Mitotic Cycle ◽  
Nitrogen Starvation ◽  
Cell Cycle Exit ◽  
Gene Encoding ◽  
Yeast Saccharomyces Cerevisiae ◽  
Protein Blocks

The puc1+ gene, encoding a G1-type cyclin from the fission yeast Schizosaccharomyces pombe, was originally isolated by complementation in the budding yeast Saccharomyces cerevisiae. Here, we report the molecular characterization of this gene and analyse its role in S. pombe. We fail to identify any function of this cyclin at the mitotic G1/S transition in S. pombe, but demonstrate that it does function in exit from the mitotic cycle. Expression of the puc1+ gene is increased during nitrogen starvation, and puc1 affects the timing of sexual development in response to starvation. Overexpression of the puc1 protein blocks sexual development, and rescues pat1ts cells, which would otherwise undergo a lethal meiosis. We conclude that puc1 contributes to negative regulation of the timing of sexual development in fission yeast, and functions at the transition between cycling and non-cycling cells.

Stress-dependent regulation of Pbh1, a BIR domain-containing protein, in the fission yeast

2006 ◽  
Vol 52 (12) ◽  
pp. 1261-1265 ◽  
Author(s):  
Nam-Chul Cho ◽  
Hyun-Jung Kang ◽  
Hye-Won Lim ◽  
Byung-Chul Kim ◽  
Eun-Hee Park ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nitrosative Stress ◽  
Nitrogen Starvation ◽  
Fusion Gene ◽  
Shuttle Vector ◽  
Upstream Region ◽  
Basal Expression ◽  
Stress Dependent ◽  
Bir Domain

To elicit the physiological roles of Pbh1, a baculoviral IAP repeat (BIR) domain-containing protein, in Schizosaccharomyces pombe, we investigated if Pbh1 expression is regulated by stress. The upstream region (1221 bp) of the pbh1 gene was fused into the promoterless β-galactosidase gene of the shuttle vector YEp367R, and the resultant fusion plasmid was named pPbh04. The synthesis of β-galactosidase from the pbh1-lacZ fusion gene was markedly enhanced by sodium nitroprusside (SNP) generating nitric oxide. The basal expression of the pbh1 gene required the presence of Pap1. Pap1 also mediated the induction of the pbh1 gene by SNP and nitrogen starvation. Pap1-dependent induction of the pbh1 gene by SNP was confirmed by the enhanced level of the pbh1 mRNA in Pap1-positive cells but not in Pap1-negative cells. Taken together, it was demonstrated that the pbh1 genes are positively regulated by nitrosative and nitrogen starvation stresses in Pap1-dependent manner.Key words: fission yeast, nitrosative stress, nutritional stress, nitrogen starvation, Pap1, Pbh1, regulation, Schizosaccharomyces pombe.

scholarly journals F-actin distribution and function during sexual differentiation in Schizosaccharomyces pombe

1998 ◽  
Vol 111 (7) ◽  
pp. 867-876 ◽  
Author(s):  
J. Petersen ◽  
O. Nielsen ◽  
R. Egel ◽  
I.M. Hagan
Keyword(s):  
Cell Cycle ◽  
Schizosaccharomyces Pombe ◽  
Cell Fusion ◽  
Sexual Differentiation ◽  
Nitrogen Starvation ◽  
Spindle Pole ◽  
Actin Binding ◽  
G1 Phase ◽  
Latrunculin A ◽  
Meiosis I

Sexual differentiation in Schizosaccharomyces pombe is induced from the G1 phase of the cell cycle by nitrogen starvation and the presence of mating pheromones. We describe the distribution of F-actin during sexual differentiation. Cortical F-actin dots have previously been shown to be restricted to one end of the rod shaped cell during the G1 phase of the cell cycle. Within half an hour of nitrogen starvation the distribution of cortical F-actin dots switched from being monopolar to bipolar. This was then reversed as the F-actin cytoskeleton repolarized so that cortical F-actin dots accumulated towards the projection tip at one end of the cell. Following cell fusion, F-actin dots were randomly scattered during the horsetail movement that precedes meiosis I and remained scattered until prometaphase or metaphase of meiosis II, when they concentrated around the nucleus. F-actin was seen on the lagging face of the nuclei which faced the partner nucleus during anaphase B of meiosis II. Early on in this anaphase F-actin was also seen on the opposite side of the nucleus, near the spindle pole body. F-actin accumulated within the spores in the mature ascus. Treatment with the actin depolymerising drug Latrunculin A showed that F-actin is required for cell fusion and spore formation. Latrunculin A treatment extended all stages from karyogamy to meiosis I. The S. pombe homologue of the actin binding protein profilin, Cdc3, was shown to be required for conjugation. Cdc3 co-localized with the formin related molecule Fus1 at the projection tip. The polarization of F-actin cortical dots to the projection tip was unaffected in the cdc3.124 mutant, but cdc3.124 mutant cells were unable to break down the cell walls between the two cells following agglutination.

scholarly journals Specific Functional Features of the Cell Integrity MAP Kinase Pathway in the Dimorphic Fission Yeast Schizosaccharomyces japonicus

2021 ◽  
Vol 7 (6) ◽  
pp. 482
Author(s):  
Elisa Gómez-Gil ◽  
Alejandro Franco ◽  
Beatriz Vázquez-Marín ◽  
Francisco Prieto-Ruiz ◽  
Armando Pérez-Díaz ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Environmental Changes ◽  
Yeast Species ◽  
Mapk Signaling ◽  
Fine Tuning ◽  
Mitogen Activated Protein Kinase ◽  
Major Influence ◽  
Cell Integrity ◽  
Mitogen Activated Protein ◽  
Functional Features

Mitogen activated protein kinase (MAPK) signaling pathways execute essential functions in eukaryotic organisms by transducing extracellular stimuli into adaptive cellular responses. In the fission yeast model Schizosaccharomyces pombe the cell integrity pathway (CIP) and its core effector, MAPK Pmk1, play a key role during regulation of cell integrity, cytokinesis, and ionic homeostasis. Schizosaccharomyces japonicus, another fission yeast species, shows remarkable differences with respect to S. pombe, including a robust yeast to hyphae dimorphism in response to environmental changes. We show that the CIP MAPK module architecture and its upstream regulators, PKC orthologs Pck1 and Pck2, are conserved in both fission yeast species. However, some of S. pombe’s CIP-related functions, such as cytokinetic control and response to glucose availability, are regulated differently in S. japonicus. Moreover, Pck1 and Pck2 antagonistically regulate S. japonicus hyphal differentiation through fine-tuning of Pmk1 activity. Chimeric MAPK-swapping experiments revealed that S. japonicus Pmk1 is fully functional in S. pombe, whereas S. pombe Pmk1 shows a limited ability to execute CIP functions and promote S. japonicus mycelial development. Our findings also suggest that a modified N-lobe domain secondary structure within S. japonicus Pmk1 has a major influence on the CIP signaling features of this evolutionarily diverged fission yeast.

scholarly journals Crosstalk between the mTOR and DNA Damage Response Pathways in Fission Yeast

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 305
Author(s):  
John-Patrick Alao ◽  
Luc Legon ◽  
Charalampos Rallis
Keyword(s):  
Dna Damage ◽  
Fission Yeast ◽  
Dna Damage Response ◽  
Cell Biology ◽  
Environmental Changes ◽  
Energy Levels ◽  
Protein Translation ◽  
Mtor Pathway ◽  
Age Related ◽  
Damage Response

Cells have developed response systems to constantly monitor environmental changes and accordingly adjust growth, differentiation, and cellular stress programs. The evolutionarily conserved, nutrient-responsive, mechanistic target of rapamycin signaling (mTOR) pathway coordinates basic anabolic and catabolic cellular processes such as gene transcription, protein translation, autophagy, and metabolism, and is directly implicated in cellular and organismal aging as well as age-related diseases. mTOR mediates these processes in response to a broad range of inputs such as oxygen, amino acids, hormones, and energy levels, as well as stresses, including DNA damage. Here, we briefly summarize data relating to the interplays of the mTOR pathway with DNA damage response pathways in fission yeast, a favorite model in cell biology, and how these interactions shape cell decisions, growth, and cell-cycle progression. We, especially, comment on the roles of caffeine-mediated DNA-damage override. Understanding the biology of nutrient response, DNA damage and related pharmacological treatments can lead to the design of interventions towards improved cellular and organismal fitness, health, and survival.

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