Identification of annexin A1 as a novel substrate for E6AP‐mediated ubiquitylation
Identification of annexin A1 as a novel substrate for E6AP‐mediated ubiquitylation
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DOI：
10.1002/jcb.22096
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发表时间：
2009-04
影响因子：
4
通讯作者：
T. Shimoji;Kyoko Murakami;Y. Sugiyama;Mami Matsuda;Sachiko Inubushi;J. Nasu;Masayuki Shirakura;Tetsuro Suzuki;T. Wakita;T. Kishino;H. Hotta;T. Miyamura;I. Shoji
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文献类型：
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作者：
T. Shimoji;Kyoko Murakami;Y. Sugiyama;Mami Matsuda;Sachiko Inubushi;J. Nasu;Masayuki Shirakura;Tetsuro Suzuki;T. Wakita;T. Kishino;H. Hotta;T. Miyamura;I. Shoji
E6相关蛋白（E6 AP）是一种细胞泛素蛋白连接酶，介导p53与高危人乳头瘤病毒E6蛋白的泛素化和降解。然而，E6 AP的生理功能知之甚少。为了鉴定E6 AP的新生物学功能，我们使用GST下拉和质谱法筛选E6 AP的结合伴侣。在这里，我们确定了膜联蛋白A1，膜联蛋白超家族的成员，作为E6 AP结合蛋白。E6 AP的异位表达增强了膜联蛋白A1在体内的降解。RNAi介导的内源性E6 AP下调增加了内源性膜联蛋白A1蛋白的水平。E6 AP与膜联蛋白A1相互作用，并以Ca 2+依赖的方式诱导其泛素化。GST pull-down分析显示，膜联蛋白A1的膜联蛋白重复结构域III对于E6 AP结合是重要的。总之，我们的数据表明，膜联蛋白A1是E6 AP介导的泛素化的一种新底物。我们的研究结果提出了E6 AP可能通过泛素-蛋白酶体途径在控制膜联蛋白A1的多种功能中发挥作用的可能性。J.细胞。106：1123-1135，2009.© 2009 Wiley‐利斯公司
E6‐associated protein (E6AP) is a cellular ubiquitin protein ligase that mediates ubiquitylation and degradation of p53 in conjunction with the high‐risk human papillomavirus E6 proteins. However, the physiological functions of E6AP are poorly understood. To identify a novel biological function of E6AP, we screened for binding partners of E6AP using GST pull‐down and mass spectrometry. Here we identified annexin A1, a member of the annexin superfamily, as an E6AP‐binding protein. Ectopic expression of E6AP enhanced the degradation of annexin A1 in vivo. RNAi‐mediated downregulation of endogenous E6AP increased the levels of endogenous annexin A1 protein. E6AP interacted with annexin A1 and induced its ubiquitylation in a Ca2+‐dependent manner. GST pull‐down assay revealed that the annexin repeat domain III of annexin A1 is important for the E6AP binding. Taken together, our data suggest that annexin A1 is a novel substrate for E6AP‐mediated ubiquitylation. Our findings raise the possibility that E6AP may play a role in controlling the diverse functions of annexin A1 through the ubiquitin‐proteasome pathway. J. Cell. Biochem. 106: 1123–1135, 2009. © 2009 Wiley‐Liss, Inc.