Browsing by Subject "Schizosaccharomyces pombe"

Now showing 1 - 4 of 4
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    cAMP-Protein Kinase A and Stress-Activated MAP Kinase 1 signaling mediate transcriptional control of autophagy in fission yeast during glucose limitation or starvation.
    (Taylor and Francis Group, 2022-09-26) Pérez Díaz, Armando Jesús; Vázquez Marín, Beatriz; Vicente Soler, Jero; Prieto Ruiz, Francisco; Soto, Teresa; Franco, Alejandro; Cansado Vizoso, José; Madrid, Marisa; Genética y Microbiología
    Macroautophagy/autophagy is an essential adaptive physiological response in eukaryotes induced during nutrient starvation, including glucose, the primary immediate carbon and energy source for most cells. Although the molecular mechanisms that induce autophagy during glucose starvation have been extensively explored in the budding yeast Saccharomyces cerevisiae, little is known about how this coping response is regulated in the evolutionary distant fission yeast Schizosaccharomyces pombe. Here, we show that S. pombe autophagy in response to glucose limitation relies on mitochondrial respiration and the electron transport chain (ETC), but, in contrast to S. cerevisiae, the AMP-activated protein kinase (AMPK) and DNA damage response pathway components do not modulate fission yeast autophagic flux under these conditions. In the presence of glucose, the cAMP-protein kinase A (PKA) signaling pathway constitutively represses S. pombe autophagy by downregulating the transcription factor Rst2, which promotes the expression of respiratory genes required for autophagy induction under limited glucose availability. Furthermore, the stress-activated protein kinase (SAPK) signaling pathway, and its central mitogen-activated protein kinase (MAPK) Sty1, positively modulate autophagy upon glucose limitation at the transcriptional level through its downstream effector Atf1 and by direct in vivo phosphorylation of Rst2 at S292. Thus, our data indicate that the signaling pathways that govern autophagy during glucose shortage or starvation have evolved differently in S. pombe and uncover the existence of sophisticated and multifaceted mechanisms that control this self-preservation and survival response.
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    Differential functional regulation of protein kinase C (PKC) orthologs in fission yeast.
    (AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2017-07) Madrid, M.; Vázquez-Marín, B.; Soto, T.; Franco, A.; Gómez-Gil, E.; Vicente-Soler, J.; Gacto, M.; Pérez, P.; Cansado Vizoso, José; Genética y Microbiología
    The two PKC orthologs Pck1 and Pck2 in the fission yeast Schizosaccharomyces pombe operate in a redundant fashion to control essential functions, including morphogenesis and cell wall biosynthesis, as well as the activity of the cell integrity pathway (CIP) and its core element the MAPK Pmk1. We show here that despite the strong structural similarity and functional redundancy of these two enzymes, the mechanisms regulating their maturation, activation, and stabilization have a remarkably distinct biological impact on both kinases. We found that in contrast to Pck2, putative in vivo phosphorylation of Pck1 within the conserved activation loop, turn and hydrophobic motifs is essential for Pck1 stability and biological functions. Constitutive Pck activation promoted dephosphorylation and destabilization of Pck2, while it enhanced Pck1 levels to interfere with proper downstream signaling to the CIP via Pck2. Importantly, whereas catalytic activity was essential for Pck1 function, Pck2 remained partially functional independently of its catalytic activity. Our findings suggest that early divergence from a common ancestor in fission yeast involved important changes in the mechanisms regulating catalytic activation and stability of PKC family members to allow for flexible and dynamic control of downstream functions, including MAPK signaling.
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    Solubilización y caracterización de la actividad trehalasa ligada a la pared celular de ascosporas de schizzosaccharomyces pombe
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1990) Gacto Fernández, Mariano José; Vicente Soler, Jerónima; Facultad de Biología
    Se ha investigado la localización de la trehalasa en ascosporas aisladas de Schiiosacchar~omycfs pombe mediante un método citoquímico basado en la formación de complejos insolubles de eugenol, producidos extracelularmente en una reacción acoplada a la actividad trehalasa. La mayor parte de la actividad enzimática detectable en extractos celulares está unida a la pared celular de las ascosporas. Por tratamiento controlado de paredes celulares con el sistema Iítico iiovoenzima es posible lograr una solubilización parcial de la trehalasa particulada. El perfil de elución obtenido por filtración molecular del enzima solubilizado de paredes indica una amplia heterogeneidad molecular, lo que sugiere una posible naturaleza glicoproteica del enzima. Los ensayos de activación y el análisis de propiedades cinéticas revelan que esta actividad se debe a una trehalasa de las pertenecientes al tipo no regulador
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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