Browsing by Subject "Formin"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Publication
    Open Access
    Metabolic control of cytokinesis by glucose cAMP–PKA signaling in fission yeast
    (Elsevier, 2025-09-19) Marín Castillo, Antonio; León Zaragoza, Sergio; Franco Sánchez, Alejandro; Vicente Soler, Jerónima; Núñez Hernández, Andrés; Soto Pino, Teresa; Madrid Mateo, María Isabel; Cansado Vizoso, José; Genética y Microbiología; Facultades de la UMU::Facultad de Biología
    Cytokinesis, the final step of cell division, must be precisely coordinated with the cellular metabolic status, yet the underlying regulatory mechanisms remain poorly understood. Here we show that in Schizosaccharomyces pombe, glucose signaling promotes cytokinesis via the evolutionarily conserved cAMP–PKA signaling pathway. Loss of the Pka1 catalytic subunit delays assembly and constriction of the contractile actomyosin ring (CAR), whereas constitutive PKA activation enhances CAR integrity and accelerates cytokinesis. Mechanistically, Pka1 downregulates the basal activity of the stress-activated MAPK Sty1 under glucose-rich conditions, thereby stabilizing the formin For3 and its nucleated actin cables, which collaborate to regulate CAR dynamics. Remarkably, cAMP–PKA signaling also facilitates cytokinesis through a parallel, actin cable–independent mechanism. Additionally, mitochondrial respiration contributes to cytokinesis in the presence of glucose through a PKA-independent pathway. These findings reveal a multilayered network that links carbon source metabolism to cytoskeletal organization and underscore the importance of tight PKA activity control for robust cell division.
  • Thumbnail Image
    Publication
    Open Access
    Myosin II regulatory light chain phosphorylation and formin availability modulate cytokinesis upon changes in carbohydrate metabolism.
    (eLife Sciences Publications, 2023-03-10) Prieto Ruiz, Francisco; Gómez Gil, Elisa; Martín García, Rebeca; Pérez Díaz, Armando J.; Vicente Soler, Jero; Franco, Alejandro; Soto, Teresa; Pérez, Pilar; Madrid, Marisa; Cansado Vizoso, José; Genética y Microbiología
    Cytokinesis, which achieves the separation of daughter cells after mitosis completion, relies in animal cells on a contractile actomyosin ring (CAR), made of actin and class II myosins, whose activity is heavily influenced by regulatory light chain (RLC) phosphorylation. However, in simple eukaryotes such as fission yeast Schizosaccharomyces pombe, regulation of CAR dynamics by RLC phosphorylation seems dispensable. We found that redundant phosphorylation at Ser35 of the S. pombe RLC homolog Rlc1 by the p21-activated kinases Pak1 and Pak2, modulates Myosin II Myo2 activity and becomes essential for cytokinesis and cell growth during respiration. Previously, we showed that the Stress Activated Protein Kinase Pathway (SAPK) MAPK Sty1 controls fission yeast CAR integrity by downregulating formin For3 levels (Gomez-Gil et al.,2020). Here we report that reduced availability of formin For3-nucleated actin filaments for the CAR is the main reason for the required control of myosin II contractile activity by RLC phosphorylation during respiration-induced oxidative stress. Hence, recovery of For3 levels with antioxidants bypasses the control of Myosin II function regulated by RLC phosphorylation to allow cytokinesis and cell proliferation during respiration. Therefore, a fine-tuned interplay between Myosin II function by Rlc1 phosphorylation and environmentally controlled actin filament availability is critical for a successful cytokinesis in response to a switch to a respiratory carbohydrate metabolism.
  • Thumbnail Image
    Publication
    Open Access
    Stress-activated MAPK signaling controls fission yeast actomyosin ring integrity by modulating formin For3 levels
    (ELIFE SCIENCES PUBLICATIONS LTD, 2020-09-11) Gómez-Gil, E.; Martín-García, R.; Vicente-Soler, J.; Franco, A.; Vázquez-Marín, B.; Prieto-Ruiz, F.; Soto, T.; Pérez, P.; Madrid, M.; Cansado Vizoso, José; Genética y Microbiología
    Cytokinesis, which enables the physical separation of daughter cells once mitosis has been completed, is executed in fungal and animal cells by a contractile actin- and myosin-based ring (CAR). In the fission yeast Schizosaccharomyces pombe, the formin For3 nucleates actin cables and also co-operates for CAR assembly during cytokinesis. Mitogen-activated protein kinases (MAPKs) regulate essential adaptive responses in eukaryotic organisms to environmental changes. We show that the stress-activated protein kinase pathway (SAPK) and its effector, MAPK Sty1, downregulates CAR assembly in S. pombe when its integrity becomes compromised during cytoskeletal damage and stress by reducing For3 levels. Accurate control of For3 levels by the SAPK pathway may thus represent a novel regulatory mechanism of cytokinesis outcome in response to environmental cues. Conversely, SAPK signaling favors CAR assembly and integrity in its close relative Schizosaccharomyces japonicus, revealing a remarkable evolutionary divergence of this response within the fission yeast clade.