Characterization of a new γTuRC subunit with WD repeats
Characterization of a new γTuRC subunit with WD repeats
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DOI：
10.1091/mbc.e02-01-0034
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发表时间：
2003-03-01
影响因子：
3.3
通讯作者：
Zheng, YX
中科院分区：
文献类型：
--
作者：
Gunawardane, RN;Martin, OC;Zheng, YX
γ-微管蛋白环复合物（gamma-tubulin ring complex，gammaTuRC）由多个蛋白质亚基组成，能使微管组装成核。虽然许多亚基的gammaTuRC已被确定，一个完整的集仍然是在任何生物体中定义。此外，这些亚基如何相互作用以组装成gammaTuRC在很大程度上仍然未知。在这里，我们报告一个新的gammaTuRC亚基，果蝇γ环蛋白WD重复（Dgp 71 WD）的表征。除了γ-微管蛋白之外，Dgp 71 WD是迄今为止鉴定的唯一不包含抓握基序的γ-TuRC组分，所述抓握基序是γ-TuRC组分中保守的特征序列。通过在Sf 9细胞中成对共表达后进行免疫沉淀，我们发现Dgp 71 WD直接与含有抓地力基序的γ TuRC亚基Dgrips 84，91，128和163相互作用，这表明Dgp 71 WD可能在γ TuRC组织中发挥支架作用。我们还表明，Dgrips 128和163，像Dgrips 84和91，可以直接与T-微管蛋白。任何这些含有抓地力基序的蛋白质与γ-微管蛋白的共表达促进γ-微管蛋白与鸟嘌呤核苷酸的结合。相反，在相同的测定中，Dgp 71 WD与γ-微管蛋白相互作用，但不促进核苷酸结合。
The gamma-tubulin ring complex (gammaTuRC), consisting of multiple protein subunits, can nucleate microtubule assembly. Although many subunits of the gammaTuRC have been identified, a complete set remains to be defined in any organism. In addition, how the subunits interact with each other to assemble into gammaTuRC remains largely unknown. Here, we report the characterization of a novel gammaTuRC subunit, Drosophila gamma ring protein with WD repeats (Dgp71WD). With the exception of gamma-tubulin, Dgp71WD is the only -gammaTuRC component identified to date that does not contain the grip motifs, which are signature sequences conserved in gammaTuRC components. By performing immunoprecipitations after pair-wise coexpression in Sf9 cells, we show that Dgp71WD directly interacts with the grip motif-containing -yTuRC subunits, Dgrips84, 91, 128, and 163, suggesting that Dgp71WD may play a scaffolding role in gammaTuRC organization. We also show that Dgrips128 and 163, like Dgrips84 and 91, can interact directly with T-tubulin. Coexpression of any of these grip motif-containing proteins with gamma-tubulin promotes gamma-tubulin binding to guanine nucleotide. In contrast, in the same assay Dgp71WD interacts with gamma-tubulin but does not facilitate nucleotide binding.