Pxl1p, a paxillin-related protein, stabilizes the actomyosin ring during cytokinesis in fission yeast.
Paxillins are a family of conserved LIM domain-containing proteins that play important roles in the function and integrity of the actin cytoskeleton. Although paxillins have been extensively characterized by cell biological and biochemical approaches, genetic studies are relatively scarce. Here, we identify and characterize a paxillin-related protein Pxl1p in the fission yeast Schizosaccharomyces pombe. Pxl1p is a component of the fission yeast actomyosin ring, a structure that is essential for cytokinesis. Cells deleted for pxl1 display a novel phenotype characterized by a splitting of the actomyosin ring in late anaphase, leading to the formation of two rings of which only one undergoes constriction. In addition, the rate of actomyosin ring constriction is slower in the absence of Pxl1p. pxl1Delta mutants display strong genetic interactions with mutants defective in IQGAP-related protein Rng2p and mutants defective in components of the fission yeast type II myosin machinery. Collectively, these results suggest that Pxl1p might cooperate with type II myosin and Rng2p-IQGAP to regulate actomyosin ring constriction as well as to maintain its integrity during constriction.
Ge
Wanzhong
W
Cell Division Laboratory, Temasek Life Sciences Laboratory and the Department of Biological Sciences, National University of Singapore, Singapore.
Balasubramanian
Mohan K
MK
D000205:Actomyosin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D048749:Cytokinesis / Q000235:genetics / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D024462:Myosin Type II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051419:Paxillin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020703:ras GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D004271:DNA, Fungal; D020690:GTPase-Activating Proteins; C101203:IQ motif containing GTPase activating protein 1; D051419:Paxillin; C533048:Pxl1 protein, S pombe; D011993:Recombinant Fusion Proteins; C114172:Rng2 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D020703:ras GTPase-Activating Proteins; D000205:Actomyosin; D024462:Myosin Type II