VCIP135 deubiquitinase and its binding protein, WAC, in p97ATPase‐mediated membrane fusion
VCIP135 deubiquitinase and its binding protein, WAC, in p97ATPase‐mediated membrane fusion
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DOI：
10.1038/emboj.2011.260
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
G. Totsukawa;Y. Kaneko;K. Uchiyama;H. Toh;Kaori Tamura;Hisao Kondo
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文献类型：
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作者：
G. Totsukawa;Y. Kaneko;K. Uchiyama;H. Toh;Kaori Tamura;Hisao Kondo
高尔基体的生物发生需要两种不同的p97膜融合途径：p97/p47和p97/p37途径。VCIP 135是两种途径所必需的，而其去泛素化活性仅为p97/p47途径所需。我们现在已经确定了一种新的VCIP 135结合蛋白，WAC。WAC定位于高尔基体以及细胞核。在高尔基体膜中，WAC参与含有VCIP 135和p97的复合物。WAC直接与VCIP 135结合并增加其去泛素化活性。siRNA实验表明，WAC是高尔基体生物合成所必需的。在体外高尔基体重组试验中，WAC仅对p97/p47介导的高尔基体重组是必需的，而对p97/p37介导的重组不是必需的。因此，WAC被认为通过激活VCIP 135的去泛素化功能在p97/p47介导的高尔基体膜融合中起作用。我们还发现，两个p97通路在ER膜融合中也起作用。体外ER重组实验表明，这两条途径都需要VCIP 135，但不需要其去泛素化活性来进行ER膜融合。这与p97介导的ER膜融合不需要WAC的发现一致。
Two distinct p97 membrane fusion pathways are required for Golgi biogenesis: the p97/p47 and p97/p37 pathways. VCIP135 is necessary for both pathways, while its deubiquitinating activity is required only for the p97/p47 pathway. We have now identified a novel VCIP135‐binding protein, WAC. WAC localizes to the Golgi as well as the nucleus. In Golgi membranes, WAC is involved in a complex containing VCIP135 and p97. WAC directly binds to VCIP135 and increases its deubiquitinating activity. siRNA experiments revealed that WAC is required for Golgi biogenesis. In anin vitroGolgi reformation assay, WAC was necessary only for p97/p47‐mediated Golgi reassembly, but not for p97/p37‐mediated reassembly. WAC is hence thought to function in p97/p47‐mediated Golgi membrane fusion by activating the deubiquitinating function of VCIP135. We also showed that the two p97 pathways function in ER membrane fusion as well. Anin vitroER reformation assay revealed that both pathways required VCIP135 but not its deubiquitinating activity for their ER membrane fusion. This was consistent with the finding that WAC is unnecessary for p97‐mediated ER membrane fusion.