GCS1, an Arf guanosine triphosphatase-activating protein in Saccharomyces cerevisiae, is required for normal actin cytoskeletal organization in vivo and stimulates actin polymerization in vitro

被引:48
作者
Blader, IJ [1 ]
Cope, MJTV
Jackson, TR
Profit, AA
Greenwood, AF
Drubin, DG
Prestwich, GD
Theibert, AB
机构
[1] Univ Alabama Birmingham, Dept Neurobiol, Birmingham, AL 35294 USA
[2] Univ Alabama Birmingham, Dept Cell Biol, Birmingham, AL 35294 USA
[3] Univ Calif Berkeley, Dept Cell & Mol Biol, Berkeley, CA 94720 USA
[4] Univ Cambridge, Mol Signalling Lab, Babraham Inst, Dept Zool, Cambridge CB2 3ES, England
[5] SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA
[6] Univ Utah, Dept Med Chem, Salt Lake City, UT 84112 USA
关键词
D O I
10.1091/mbc.10.3.581
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Recent cloning of a rat brain phosphatidylinositol 3,4,5-trisphosphate binding protein, centaurin alpha, identified a novel gene family based on homology to an amino-terminal zinc-binding domain, in Saccharomyces cerevisiae, the protein with the highest homology to centaurin alpha is Gcs1p, the product of the GCS1 gene. GCS1 was originally identified as a gene conditionally required for the reentry of cells into the cell cycle after stationary phase growth. Gcs1p was previously characterized as a guanosine triphosphatase-activating protein for the small guanosine triphosphatase Arf1, and gcs1 mutants displayed vesicle-trafficking defects. Here, we have shown that similar to centaurin alpha, recombinant Gcs1p bound phosphoinositide-based affinity resins with high affinity and specificity. A novel GCS1 disruption strain (gcs1 Delta) exhibited morphological defects, as well as mislocalization of cortical actin patches. gcs1 Delta was hypersensitive to the actin monomer-sequestering drug, latrunculin-B. Synthetic lethality was observed between null alleles of GCS1 and SLA2, the gene encoding a protein involved in stabilization of the actin cytoskeleton. In addition, synthetic growth defects were observed between null alleles of GCS1 and SAC6, the gene encoding the yeast fimbrin homologue. Recombinant Gcs1p bound to actin filaments, stimulated actin polymerization, and inhibited actin depolymerization in vitro. These data provide in vivo and in vitro evidence that Gcs1p interacts directly with the actin cytoskeleton in S. cerevisiae.
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页码:581 / 596
页数:16
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