Cdc42-interacting protein 4 mediates binding of the Wiskott-Aldrich syndrome protein to microtubules
Cdc42-interacting protein 4 mediates binding of the Wiskott-Aldrich syndrome protein to microtubules
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DOI：
10.1074/jbc.275.11.7854
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发表时间：
2000-03-17
影响因子：
4.8
通讯作者：
Stewart, DM
中科院分区：
文献类型：
--
作者：
Tian, L;Nelson, DL;Stewart, DM
Wiskott-Aldrich综合征是一种遗传性X-连锁免疫缺陷，其特征为血小板减少症、湿疹和淋巴恶性肿瘤倾向。受影响的个体的淋巴细胞有细胞骨架异常，单核细胞显示受损的运动。Wiskott-Aldrich综合征蛋白（WASP）是一种参与细胞骨架组织的多结构域蛋白。在双杂交筛选中，我们确定了蛋白Cdc 42相互作用蛋白4（CIP 4）作为WASP相互作用。CIP 4与WASP一样，是一种参与细胞骨架组织的Cdc 42效应蛋白。我们发现，WASP-CIP 4的相互作用是介导的结合的Src同源性3结构域的CIP 4的富含脯氨酸的部分WASP。Cdc 42不需要这种相互作用。CIP 4和绿色荧光蛋白-WASP在COS-7细胞中的GO表达导致WASP与微管的结合。体外实验表明，CIP 4通过其NH 2末端与微管结合。CIP 4负责与活性Cdc 42结合的区域定位于氨基酸383-417，并且突变I398 S废除结合。CIP 4的Cdc 42结合结构域的缺失并不影响WASP与微管在体内的共定位。我们的结论是，CIP 4可以介导的协会WASP与微管。这可能有助于WASP转运到造血细胞中的底物粘附位点。
The Wiskott-Aldrich syndrome is an inherited X-linked immunodeficiency characterized by thrombocytopenia, eczema, and a tendency toward lymphoid malignancy. Lymphocytes from affected individuals have cytoskeletal abnormalities, and monocytes show impaired motility. The Wiskott-Aldrich syndrome protein (WASP) is a multi-domain protein involved in cytoskeletal organization. In a two-hybrid screen, we identified the protein Cdc42-interacting protein 4 (CIP4) as a WASP interactor. CIP4, like WASP, is a Cdc42 effector protein involved in cytoskeletal organization. We found that the WASP-CIP4 interaction is mediated by the binding of the Src homology 3 domain of CIP4 to the proline-rich segment of WASP. Cdc42 was not required for this interaction. Go-expression of CIP4 and green fluorescent protein-WASP in COS-7 cells led to the association of WASP with microtubules. In vitro experiments showed that CIP4 binds to microtubules via its NH2 terminus. The region of CIP4 responsible for binding to active Cdc42 was localizes to amino acids 383-417, and the mutation I398S abrogated binding. Deletion of the Cdc42-binding domain of CIP4 did not affect the colocalization of WASP with microtubules in vivo. We conclude that CIP4 can mediate the association of WASP with microtubules. This may facilitate transport of WASP to sites of substrate adhesion in hematopoietic cells.