ErbB3 (HER3) interaction with the p85 regulatory subunit of phosphoinositide 3-kinase
ErbB3 (HER3) interaction with the p85 regulatory subunit of phosphoinositide 3-kinase
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DOI：
10.1042/bj3330757
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发表时间：
1998-08-01
影响因子：
4.1
通讯作者：
Koland, JG
中科院分区：
文献类型：
--
作者：
Hellyer, NJ;Cheng, K;Koland, JG
ErbB3(HER3)是ErbB受体家族中一个独特的成员，它缺乏固有的蛋白酪氨酸激酶活性，并且含有6个Tyr-xaa-xaa-Met(YXXM)与磷脂酰肌醇3-激酶P85调节亚基的SH2结构域的共同结合位点。ErbB3也有一个富含Pro的序列，它形成了P85的SH3结构域的共同结合位点。在这里，我们通过酵母双杂交系统的独特应用研究了ErbB3和P85的相互作用结构域。为了使ErbB3的C-末端结构域在酵母体系中被磷酸化，我们开发了一个含有表皮生长因子受体蛋白酪氨酸激酶结构域的嵌合体ErbB3分子。我们还产生了几个ErbB3缺失和Tyr-->；Phe位点特异性突变体，并观察到单个ErbB3 YXXM基序是ErbB3与P85结合的必要条件和充分条件。将多个YXXM基序整合到ErbB3的C-末端使ErbB3/P85有更强的相互作用。ErbB3富含脯氨酸的区域不是与P85相互作用所必需的。然而，P85SH3结构域的缺失或突变都降低了观察到的ErbB3/P85关联。此外，通过体外实验检测到ErbB3/P85SH3结构域的相互作用。这些结果与磷酸化的ErbB3 YXXM基序对与P85的串联SH2结构域相互作用的模型一致。尽管P85SH3结构域被认为是有贡献的，但N端和C端的SH2结构域似乎主要负责P85和ErbB3的高亲和力联系。
ErbB3 (HER3), a unique member of the ErbB receptor family, lacks intrinsic protein tyrosine kinase activity and contains six Tyr-Xaa-Xaa-Met (YXXM) consensus binding sites for the SH2 domains of the p85 regulatory subunit of phosphoinositide 3-kinase. ErbB3 also has a proline-rich sequence that forms a consensus binding site for the SH3 domain of p85. Here we have investigated the interacting domains of ErbB3 and p85 by a unique application of the yeast two-hybrid system. A chimaeric ErbB3 molecule containing the epidermal growth factor receptor protein tyrosine kinase domain was developed so that the C-terminal domain of ErbB3 could become phosphorylated in the yeast system. We also generated several ErbB3 deletion and Tyr --> Phe site-specific mutants, and observed that a single ErbB3 YXXM motif was necessary and sufficient for the association of ErbB3 with p85. The incorporation of multiple YXXM motifs into the ErbB3 C-terminus enabled a stronger ErbB3/p85 interaction. The proline-rich region of ErbB3 was not necessary for interaction with p85. However, either deletion or mutation of the p85 SH3 domain decreased the observed ErbB3/p85 association. Additionally an ErbB3/p85 SH3 domain interaction was detected by an assay in vitro. These results were consistent with a model in which pairs of phosphorylated ErbB3 YXXM motifs co-operate in binding to the tandem SH2 domains of p85. Although a contributing role for the p85 SH3 domain was suggested, the N- and C-terminal SH2 domains seemed to be primarily responsible for the high-affinity association of p85 and ErbB3.