Part of Ran is associated with AKAP450 at the centrosome:: Involvement in microtubule-organizing activity
Part of Ran is associated with AKAP450 at the centrosome:: Involvement in microtubule-organizing activity
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DOI：
10.1091/mbc.e02-11-0773
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发表时间：
2003-10-01
影响因子：
3.3
通讯作者：
Tassin, AM
中科院分区：
文献类型：
--
作者：
Keryer, G;Di Fiore, B;Tassin, AM
小的Ran GT3是核质运输的关键调节因子，也参与微管组装和核膜形成。在此，我们通过免疫荧光，免疫电子显微镜和生化分析表明，一部分RAN与整个细胞周期的中心体紧密相关。RAN与中心体的相互作用是由中心体基质A激酶锚定蛋白（AKAP 450）介导的。因此，当AKAP 450从中心体离域时，Ran也离域，因此，微管再生长或锚定被改变，尽管γ-微管蛋白与中心体持续缔合。此外，Ran被招募到非洲爪蟾精子中心体激活微管成核。我们还表明，中心体蛋白，如centrin和pericentrin，但不是γ-微管蛋白，AKAP 450，或ninein，进行核质交换，因为它们集中在细胞核出口抑制后，由链霉素B。总之，这些结果表明一个具有挑战性的可能性，即，中心体的活动可能取决于核质交换的中心体蛋白和本地RAN依赖的中心体浓度。
The small Ran GTPase, a key regulator of nucleocytoplasmic transport, is also involved in microtubule assembly and nuclear membrane formation. Herein, we show by immunofluorescence, immunoelectron microscopy, and biochemical analysis that a fraction of Ran is tightly associated with the centrosome throughout the cell cycle. Ran interaction with the centrosome is mediated by the centrosomal matrix A kinase anchoring protein (AKAP450). Accordingly, when AKAP450 is delocalized from the centrosome, Ran is also delocalized, and as a consequence, microtubule regrowth or anchoring is altered, despite the persisting association of gamma-tubulin with the centrosome. Moreover, Ran is recruited to Xenopus sperm centrosome during its activation for microtubule nucleation. We also demonstrate that centrosomal proteins such as centrin and pericentrin, but not gamma-tubulin, AKAP450, or ninein, undertake a nucleocytoplasmic exchange as they concentrate in the nucleus upon export inhibition by leptomycin B. Together, these results suggest a challenging possibility, namely, that centrosome activity could depend upon nucleocytoplasmic exchange of centrosomal proteins and local Ran-dependent concentration at the centrosome.