CIN85 is localized at synapses and forms a complex with S-SCAM via Dendrin
CIN85 is localized at synapses and forms a complex with S-SCAM via Dendrin
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DOI：
10.1093/jb/mvj105
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发表时间：
2006-05-01
影响因子：
2.7
通讯作者：
Hata, Yutaka
中科院分区：
文献类型：
--
作者：
Kawata, Akira;Lida, Junko;Hata, Yutaka
膜相关鸟苷酸激酶倒置（MAGI）-1在非神经元细胞中的细胞连接处起支架作用，而S-SCAM，其神经元亚型，参与突触的组织。通过酵母双杂交筛选肾脏cDNA文库来寻找MAGI-1相互作用蛋白，产生了树突状蛋白。由于dendrin最初被报道为脑特异性突触后蛋白，我们测试了dendrin和S-SCAM之间的相互作用，并发现dendrin结合到S-SCAM的WW结构域。已知Dendrin是树枝状翻译的，但其功能在很大程度上是未知的。为了深入了解相互作用的生理意义，我们使用dendrin作为诱饵进行了第二次酵母双杂交筛选。我们确定了CIN 85，一种内吞支架蛋白，作为一个假定的树突状蛋白相互作用。免疫细胞化学和亚细胞分级分析支持CIN 85的突触定位。CIN 85的第一个SH 3结构域和C-末端区域分别与dendrin的富含脯氨酸的区域和N-末端区域结合。体外实验表明，树突状蛋白与CIN 85和S-SCAM形成三元复合物，并且这种复合物的形成促进树突状蛋白和S-SCAM向CIN 85积累的囊泡样结构的募集。
Membrane-associated guanylatekinase inverted (MAGI)-1 plays a role as a scaffold at cell junctions in non-neuronal cells, while S-SCAM, its neuronal isoform, is involved in the organization of synapses. A search for MAGI-1-interacting proteins by yeast two-hybrid screening of a kidney cDNA library yielded dendrin. As dendrin was originally reported as a brain-specific postsynaptic protein, we tested the interaction between dendrin and S-SCAM and revealed that dendrin binds to the WW domains of S-SCAM. Dendrin is known to be dendritically translated but its function is largely unknown. To gain insights into the physiological meaning of the interaction, we performed a second yeast two-hybrid screening using dendrin as a bait. We identified CIN85, an endocytic scaffold protein, as a putative dendrin-interactor. Immunocytochemistry and subcellular fractionation analysis supported the synaptic localization of CIN85. The first SH3 domain and the C-terminal region of CIN85 bind to the proline-rich region and the N-terminal region of dendrin, respectively. In vitro experiments suggest that dendrin forms a ternary complex with CIN85 and S-SCAM and that this complex formation facilitates the recruitment of dendrin and S-SCAM to vesicle-like structures where CIN85 is accumulated.