Etd1p is a novel protein that links the SIN cascade with cytokinesis.
In animal cells, cytokinesis occurs by constriction of an actomyosin ring. In fission yeast cells, ring constriction is triggered by the septum initiation network (SIN), an SPB-associated GTPase-regulated kinase cascade that coordinates exit from mitosis with cytokinesis. We have identified a novel protein, Etd1p, required to trigger actomyosin ring constriction in fission yeasts. This protein is localised at the cell tips during interphase. In mitosis, it relocates to the medial cortex region and, coincident with cytokinesis, it assembles into the actomyosin ring by association to Cdc15p. Relocation of Etd1p from the plasma membrane to the medial ring is triggered by SIN signalling and, reciprocally, relocation of the Sid2p-Mob1p kinase complex from the SPB to the division site, a late step in the execution of the SIN, requires Etd1p. These results suggest that Etd1p coordinates the mitotic activation of SIN with the initiation of actomyosin ring constriction. Etd1p peaks during cytokinesis and is degraded by the ubiquitin-dependent 26S-proteasome pathway at the end of septation, providing a mechanism to couple inactivation of SIN to completion of cytokinesis.
Daga
Rafael R
RR
Centro Andaluz de Biología del Desarrollo, CSIC/Universidad Pablo de Olavide, Carretera de Utrera Km1, Sevilla, Spain.
Lahoz
Aurelia
A
Muñoz
Manuel J
MJ
Moreno
Sergio
S
Jimenez
Juan
J
D000205:Actomyosin / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis; D000431:Ethanol / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000502:physiology; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D021381:Protein Transport; D012568:Schizosaccharomyces / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
C082279:CDC15 protein; D018797:Cell Cycle Proteins; D029702:Schizosaccharomyces pombe Proteins; D000431:Ethanol; D000205:Actomyosin; D011494:Protein Kinases; C113816:Sid2 protein, S pombe; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins