Negative control of cytokinesis by stress-activated MAPK signaling

Abstract

Mitogen-activated protein kinase (MAPK) signalling pathways regulate multiple cellular functions in eukaryotic organisms in response to environmental cues, including the dynamic remodeling of the actin cytoskeleton. The fission yeast S. pombe is an optimal model to investigate the conserved regulatory mechanisms of cytokinesis, which relies in an actomyosin-based contractile ring (CAR) that prompts the physical separation of daughter cells during cellular division. Our group has recently shown that p38 MAPK ortholog Sty1, the core component of the stress-activated pathway (SAPK), negatively modulates CAR assembly and integrity in S. pombe during actin cytoskeletal damage induced with Latrunculin A and in response to environmental stress. This response involves downregulation of protein levels of the formin For3, which assembles actin filaments for cables and the CAR, likely through an ubiquitin-mediated degradation mechanism. Contrariwise, Sty1 function positively reinforces CAR assembly during stress in the close relative dimorphic fission yeast S. japonicus. The opposite effect of SAPK signaling on CAR integrity may represent an evolutionary refined adaptation to cope with the marked differences in cytokinesis onset in both fission yeast species.

Myosin II regulatory light chain phosphorylation and formin availability modulate cytokinesis upon changes in carbohydrate metabolism

“…However, further evidence demonstrated that actin filaments nucleated by For3, the formin that assembles the actin cables that participate in polarized secretion and growth, also contribute to CAR formation in fission yeast [24, 25]. In turn, the activated SAPK pathway down-regulates in S. pombe CAR assembly and stability in response to stress by reducing For3 levels [25, 63]. Like animal cells, fission yeast respiratory metabolism induces endogenous oxidative stress with electron leakage from the mitochondrial electron transport chain [49].…”

Low‐Molecular Weight Compounds that Extend the Chronological Lifespan of Yeasts, Saccharomyces cerevisiae, and Schizosaccharomyces pombe

“…[ 56 ] Sty1 is an ortholog of mammalian p38. [ 57,58 ] and the activation of the Sty1 pathway extends CLS in fission yeast. [ 59,60 ] Myriocin also extends the lifespan of nematodes, and a mutant of serine palmitoyl transferase 1 ( spt‐1 ), the target of myriocin, extends lifespan.…”

ecl family genes: Factors linking starvation and lifespan extension in Schizosaccharomyces pombe

“…The stress-activated protein kinase pathway plays a critical role in S. pombe by modulating the cell cycle and the general adaptive response to stress, and its central element, the p38 ortholog mitogen-activated protein kinase (MAPK) Sty1, is activated in response to various cues including hyperosmotic stress, heat shock, cold stress, oxidative stress, and nutrient starvation (Madrid et al, 2021;Morigasaki et al, 2013;Morigasaki & Shiozaki, 2010).…”

“…The stress‐activated protein kinase pathway plays a critical role in S. pombe by modulating the cell cycle and the general adaptive response to stress, and its central element, the p38 ortholog mitogen‐activated protein kinase (MAPK) Sty1, is activated in response to various cues including hyperosmotic stress, heat shock, cold stress, oxidative stress, and nutrient starvation (Madrid et al, 2021; Morigasaki et al, 2013; Morigasaki & Shiozaki, 2010). In S. pombe , oxidative stress is transmitted intracellularly through a multistep phosphorelay system consisting of the sensor kinases Mak1, Mak2, and Mak3; histidine‐containing phosphotransfer protein Mpr1; and response regulator Mcs4 (Lushchak, 2010; Papadakis & Workman, 2015; Vivancos et al, 2006).…”