Browsing by Subject "Pmk1"

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    MAPK‑dependent control of mitotic progression in S. pombe
    (BioMed Central, 2024-03-25) Iglesias Romero, Ana Belén; Soto Pino, Teresa; Flor Parra, Ignacio; Salas Pino, Silvia; Ruiz Romero, Gabriel; Gould, Kathleen L.; Cansado Vizoso, José; Daga, Rafael R.; Genética y Microbiología; Facultades de la UMU::Facultad de Biología
    Background: Mitogen-activated protein kinases (MAPKs) preserve cell homeostasis by transducing physicochemical fluctuations of the environment into multiple adaptive responses. These responses involve transcriptional rewiring and the regulation of cell cycle transitions, among others. However, how stress conditions impinge mitotic progression is largely unknown. The mitotic checkpoint is a surveillance mechanism that inhibits mitotic exit in situations of defective chromosome capture, thus preventing the generation of aneuploidies. In this study, we investigate the role of MAPK Pmk1 in the regulation of mitotic exit upon stress. Results: We show that Schizosaccharomyces pombe cells lacking Pmk1, the MAP kinase effector of the cell integrity pathway (CIP), are hypersensitive to microtubule damage and defective in maintaining a metaphase arrest. Epistasis analysis suggests that Pmk1 is involved in maintaining spindle assembly checkpoint (SAC) signaling, and its deletion is additive to the lack of core SAC components such as Mad2 and Mad3. Strikingly, pmk1Δ cells show up to twofold increased levels of the anaphase-promoting complex (APC/C) activator Cdc20Slp1 during unperturbed growth. We demonstrate that Pmk1 physically interacts with Cdc20Slp1 N-terminus through a canonical MAPK docking site. Most important, the Cdc20Slp1 pool is rapidly degraded in stressed cells undergoing mitosis through a mechanism that requires MAPK activity, Mad3, and the proteasome, thus resulting in a delayed mitotic exit. Conclusions: Our data reveal a novel function of MAPK in preventing mitotic exit and activation of cytokinesis in response to stress. The regulation of Cdc20Slp1 turnover by MAPK Pmk1 provides a key mechanism by which the timing of mitotic exit can be adjusted relative to environmental conditions.
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    Specific functional features of the cell integrity MAP Kinase pathway in the dimorphic fission yeast Schizosaccharomyces japonicus
    (MDPI, 2021-06-14) Gómez Gil, Elisa; Franco Sánchez, Alejandro; Vázquez Marín, Beatriz; Prieto Ruiz, Francisco; Pérez Díaz, Armando Jesús; Vicente Soler, Jerónima; Madrid Mateo, María Isabel; Soto Pino, Teresa; Cansado Vizoso, José; Genética y Microbiología; Facultades de la UMU::Facultad de Biología
    Mitogen activated protein kinase (MAPK) signaling pathways execute essential functions in eu-karyotic organisms by transducing extracellular stimuli into adaptive cellular responses. In the fis-sion 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 re-spect 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 re-vealed 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.2021