GRB2 SH3 BINDING TO PEPTIDES FROM SOS - EVALUATION OF A GENERAL-MODEL FOR SH3-LIGAND INTERACTIONS
GRB2 SH3 BINDING TO PEPTIDES FROM SOS - EVALUATION OF A GENERAL-MODEL FOR SH3-LIGAND INTERACTIONS
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DOI：
10.1016/1074-5521(95)90080-2
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发表时间：
1995-01-01
影响因子：
--
通讯作者：
SCHREIBER, SL
中科院分区：
文献类型：
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作者：
SIMON, JA;SCHREIBER, SL
背景：Grb 2。在从受体酪氨酸激酶到Ras的信号转导中作为接头蛋白。它通过其中心SH 2结构域与细胞表面受体的胞质尾区上的磷酸酪氨酸结合，并通过两个SH 3结构域与其直接下游靶标Sos结合。Grb 2-Sos相互作用的基础尚未完全了解。我们以前提出了一个模型的SH 3结构域结合特异性，基于两个解决方案的结构的Src SH 3结构域与高亲和力的配体，其中的配体结合在一个聚脯氨酸II型构象在两个不同的方向，I类和II类。结果：从人Sos蛋白羧基端（氨基酸1000-1333）得到6个连续片段，每个片段含有一个潜在的SH 3结合位点，在大肠杆菌中得到表达。coli中表达GST融合蛋白。这些蛋白质中的四个被预测与SH 3结构域相关联。氨基末端Grb 2 SH 3结构域被证明强烈结合只有这四个fragments.Conclusions：我们已经使用了一个一般模型SH 3配体相互作用来预测Grb 2 SH 3与hSos蛋白的相互作用的性质。结合Grb 2的四种hSos序列的比较。揭示了与预测的II类结合相互作用一致的PXXPXR基序的偏好。Grb 2和hSos肽之间的相互作用主要是通过氨基末端SH 3结构域，尽管羧基末端SH 3结构域可以增加Grb 2-hSos复合物的总体稳定性。
Background: Grb2. acts as an adaptor protein in the transduction of signals from receptor tyrosine kinases to Ras. It binds to phosphotyrosine on the cytoplasmic tail of cell-surface receptors via its central SH2 domain, and to its immediate downstream target, Sos, via two SH3 domains. The basis of the Grb2-Sos interaction is not fully understood. We previously proposed a model for SH3 domain binding specificity, based on two solution structures of the Src SH3 domain complexed with high-affinity ligands, in which the ligands are bound in a polyproline type II conformation in two distinct orientations, class I and class II. Here, me have used this model to predict the identity and orientation of Grb2 SH3 ligands in the human Sos protein.Results: Six contiguous fragments from the carboxy-terminal portion of hSos (amino acids 1000-1333), each containing a single potential SH3 binding site, were expressed in E. coli as GST fusion proteins. Four of these proteins were predicted to associate with SH3 domains. The amino-terminal Grb2 SH3 domain was shown to bind strongly to only these four fragments.Conclusions: We have used a general model for SH3- ligand interactions to predict the nature of Grb2 SH3 interactions with the hSos protein. Comparison of the four hSos sequences that bind Grb2. revealed a preference for the PXXPXR motif consistent with the predicted class II-type binding interaction. The interaction between Grb2 and hSos peptides is predominantly via the aminoterminal SH3 domain, although the carboxy-terminal SH3 domain may increase the Overall stability of the Grb2-hSos complex.