The BNIP-2 and Cdc42GAP homology domain of BNIP-2 mediates its homophilic association and heterophilic interaction with Cdc42GAP
The BNIP-2 and Cdc42GAP homology domain of BNIP-2 mediates its homophilic association and heterophilic interaction with Cdc42GAP
复制标题
DOI：
10.1074/jbc.m004897200
复制
发表时间：
2000-12-01
影响因子：
4.8
通讯作者：
Guy, GR
中科院分区：
文献类型：
--
作者：
Low, BC;Seow, KT;Guy, GR
我们最近表明，BNIP-2 是成纤维细胞生长因子受体酪氨酸激酶的假定底物，并且它对小 GTP 酶 Cdc42 具有 GTP 酶激活活性。 BNIP-2 的羧基末端与 Cdc42GAP 的非催化结构域具有高度同源性，称为 BCH（BNIP-2 和 Cdc42GAP 同源性）结构域。尽管与任何已知的 GTP 酶激活蛋白 (GAP) 催化结构域缺乏明显的同源性，但 BNIP-2 的 BCH 结构域结合 Cdc42，并通过一种新的精氨酸补丁基序刺激 GTPase 活性，该基序类似于 Cdc42 同二聚体中的一个贡献伙伴所采用的基序。相比之下，Cdc42GAP 的 BCH 结构域虽然可以结合 Cdc42，但没有催化活性。域可能在细胞中发挥其他作用。使用谷胱甘肽S-转移酶重组蛋白、免疫沉淀研究和酵母双杂交测定，发现BNIP-2和Cdc42GAP可以通过其保守的BCH结构域形成同源和异源复合物。 BNIP-2 BCH 同二聚体复合物的分子建模和随后的缺失诱变有助于将 (RRKMP221)-R-217 区域识别为 BMP-S 内的主要 BCH 相互作用位点。相比之下，删除精氨酸补丁 (RRLRK239)-R-235（GAP 活性所必需的）或区域 (EYV290)-E-288（Cdc42 结合序列）对 BCH-BCH 相互作用没有影响。广泛的数据库搜索表明，BCH 结构域在物种间高度保守。结果表明，BNIP-2 和 Cdc42GAP 的 BCH 结构域代表了一种新型蛋白质-蛋白质相互作用结构域，可能决定和/或改变这些分子的生理作用。
We recently showed that BNIP-2 is a putative substrate of the fibroblast growth factor receptor tyrosine kinase and it possesses GTPase-activating activity toward the small GTPase, Cdc42. The carboxyl terminus of BNIP-2 shares high homology to the non-catalytic do main of Cdc42GAP, termed BCH (for BNIP-2 and Cdc42GAP homology) domain. Despite the lack of obvious homology to any known catalytic domains of GTPase-activating proteins (GAPs), the BCH domain of BNIP-2 bound Cdc42 and stimulated the GTPase activity via a novel arginine-patch motif similar to that employed by one contributing partner in a Cdc42 homodimer, In contrast, the BCH domain of Cdc42GAP, although it can bind Cdc42, is catalytically inactive, This raises the possibility that these domains might have other roles in the cell. Using glutathione S-transferase recombinant proteins, immunoprecipitation studies, and yeast two-hybrid assays, it was found that BNIP-2 and Cdc42GAP could form homo and hetero complexes via their conserved BCH domains. Molecular modeling of the BNIP-2 BCH homodimer complex and subsequent deletion mutagenesis helped to identify the region (RRKMP221)-R-217 as the major BCH interaction site within BMP-S. In comparison, deletion of either the arginine-patch (RRLRK239)-R-235 (necessary for GAP activity) or region (EYV290)-E-288 (a Cdc42 binding sequence) had no effect on BCH-BCH interaction. Extensive data base searches showed that the BCH domain is highly conserved across species. The results suggest that BCH domains of BNIP-2 and Cdc42GAP represent a novel protein-protein interaction domain that could potentially determine and/or modify the physiological roles of these molecules.