The ubiquitin-conjugating enzymes UbcH7 and UbcH8 interact with RING finger/IBR motif-containing domains of HHARI and H7-AP1
The ubiquitin-conjugating enzymes UbcH7 and UbcH8 interact with RING finger/IBR motif-containing domains of HHARI and H7-AP1
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DOI：
10.1074/jbc.274.43.30963
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发表时间：
1999-10-22
影响因子：
4.8
通讯作者：
Robinson, PA
中科院分区：
文献类型：
--
作者：
Moynihan, TP;Ardley, HC;Robinson, PA
蛋白质的泛素化似乎是由泛素结合酶(E2S)和泛素蛋白连接酶(E3S)之间的特异性相互作用所介导的。然而，仅在少数E2s中鉴定出同源E3s和/或底物蛋白，为了鉴定能与人E2UbcH7相互作用的蛋白质，进行了酵母双杂交筛选。鉴定了两种蛋白质，分别命名为人果蝇同源基因(HHARI)和UbcH7相关蛋白(H7-AP1)。这两种广泛表达的蛋白质的特征都是存在环指和环指之间的(IBR)结构域。这两种蛋白质之间没有其他明显的结构相似性。体外结合研究表明，这些蛋白与UbcH7的相互作用涉及N末端的环指基序(HHARI)和IBR结构域(HHARI和H7-AP1)。此外，这两种蛋白与UbcH7的结合是特异的，因为HHARI和H7-AP1都可以与密切相关的E2，UbcH8结合，但不能与无关的E2s UbcH5和UbcH1结合。虽然目前尚不清楚HHARI和H7-AP1是否作为UbcH7的底物或代表具有E3活性的蛋白质，但我们的数据表明，RING FING/IBR蛋白质的子集在功能上与泛素/蛋白酶体途径有关。
Ubiquitinylation of proteins appears to be mediated by the specific interplay between ubiquitin-conjugating enzymes (E2s) and ubiquitin-protein ligases (E3s). However, cognate E3s and/or substrate proteins have been identified for only a few E2s, To identify proteins that can interact with the human E2 UbcH7, a yeast two-hybrid screen was performed. Two proteins were identified and termed human homologue of Drosophila ariadne (HHARI) and UbcH7-associated protein (H7-AP1). Both proteins, which are widely expressed, are characterized by the presence of RING finger and in between RING fingers (IBR) domains. No other overt structural similarity was observed between the two proteins. In vitro binding studies revealed that an N-terminal RING finger motif (HHARI) and the IBR domain (HHARI and H7-AP1) are involved in the interaction of these proteins with UbcH7. Furthermore, binding of these two proteins to UbcH7 is specific insofar that both HHARI and H7-AP1 can bind to the closely related E2, UbcH8, but not to the unrelated E2s UbcH5 and UbcH1. Although it is not clear at present whether HHARI and H7-AP1 serve, for instance, as substrates for UbcH7 or represent proteins with E3 activity, our data suggests that a subset of RING finger/IBR proteins are functionally linked to the ubiquitin/proteasome pathway.