Venkatram Srinivas, Tasto Joseph J, Feoktistova Anna, Jennings Jennifer L, Link Andrew J, Gould Kathleen L
Department of Cell and Developmental Biology, Howard Hughes Medical Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Mol Biol Cell. 2004 May;15(5):2287-301. doi: 10.1091/mbc.e03-10-0728. Epub 2004 Mar 5.
The gamma-tubulin complex, via its ability to organize microtubules, is critical for accurate chromosome segregation and cytokinesis in the fission yeast, Schizosaccharomyces pombe. To better understand its roles, we have purified the S. pombe gamma-tubulin complex. Mass spectrometric analyses of the purified complex revealed known components and identified two novel proteins (i.e., Mbo1p and Gfh1p) with homology to gamma-tubulin-associated proteins from other organisms. We show that both Mbo1p and Gfh1p localize to microtubule organizing centers. Although cells deleted for either mbo1(+) or gfh1(+) are viable, they exhibit a number of defects associated with altered microtubule function such as defects in cell polarity, nuclear positioning, spindle orientation, and cleavage site specification. In addition, mbo1Delta and gfh1Delta cells exhibit defects in astral microtubule formation and anchoring, suggesting that these proteins have specific roles in astral microtubule function. This study expands the known roles of gamma-tubulin complex components in organizing different types of microtubule structures in S. pombe.
γ-微管蛋白复合体通过其组织微管的能力，对于裂殖酵母粟酒裂殖酵母中准确的染色体分离和胞质分裂至关重要。为了更好地理解其作用，我们纯化了粟酒裂殖酵母的γ-微管蛋白复合体。对纯化复合体的质谱分析揭示了已知成分，并鉴定出两种与其他生物体中γ-微管蛋白相关蛋白具有同源性的新蛋白（即Mbo1p和Gfh1p）。我们表明，Mbo1p和Gfh1p都定位于微管组织中心。虽然缺失mbo1⁺或gfh1⁺的细胞是有活力的，但它们表现出许多与微管功能改变相关的缺陷，如细胞极性、核定位、纺锤体取向和分裂位点指定方面的缺陷。此外，mbo1Δ和gfh1Δ细胞在星体微管形成和锚定方面表现出缺陷，表明这些蛋白在星体微管功能中具有特定作用。这项研究扩展了γ-微管蛋白复合体成分在粟酒裂殖酵母中组织不同类型微管结构方面的已知作用。
