Evidence for ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) self-association through PDZ-PDZ interactions
Evidence for ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) self-association through PDZ-PDZ interactions
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DOI：
10.1074/jbc.c000092200
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发表时间：
2000-08-11
影响因子：
4.8
通讯作者：
Doctor, RB
中科院分区：
文献类型：
--
作者：
Fouassier, L;Yun, CC;Doctor, RB
Ezrin-radixin-moesin（ERM）-binding phosphoprotein 50（EBP 50）是一种多功能的膜-细胞骨架连接蛋白，通过其两个PDZ结构域与特定的膜整合蛋白的COOH-尾结合。这些EBP 50结合相互作用涉及将相互作用的蛋白质组隔离到共同的微结构域中，调节相互作用蛋白质的活性，以及调节膜蛋白运输。由于只有两个PDZ结构域，目前还不清楚EBP 50如何形成多蛋白复合物。其他PDZ蛋白通过寡聚化增加其蛋白质相互作用的广度和多样性。假设EBP 50自我关联以放大其功能能力，胆管上皮细胞蛋白与EBP 50融合蛋白的远蛋白质印迹显示EBP 50结合至50 kDa蛋白。通过双向凝胶电泳或免疫沉淀分离的EBP 50的Far-Western印迹证明，50-kDa结合配偶体本身就是EBP 50。此外，共转染/共沉淀研究表明，EBP 50-EBP 50结合相互作用的体外分析表明，它是饱和的，并且具有相对高的亲和力。对截短的EBP 50蛋白的分析表明EBP 50的自结合是通过其PDZ结构域介导的。自缔合的能力为EBP 50提供了一种机制，以扩大其形成多蛋白复合物和调节膜转运事件的能力。
Ezrin-radixin-moesin (ERM)-binding phosphoprotein 50 (EBP50) is a versatile membrane-cytoskeleton linking protein that binds to the COOH-tail of specific integral membrane proteins through its two PDZ domains. These EBP50 binding interactions have been implicated in sequestering interactive sets of proteins into common microdomains, regulating the activity of interacting proteins, and modulating membrane protein trafficking. With only two PDZ domains, it is unclear how EBP50 forms multiprotein complexes. Other PDZ proteins increase their breadth and diversity of protein interactions through oligomerization. Hypothesizing that EBP50 self-associates to amplify its functional capacity, far-Western blotting of cholangiocyte epithelial cell proteins with EBP50 fusion protein revealed that EBP50 binds to a 50-kDa protein. Far-Western blotting of EBP50 isolated by two-dimensional gel electrophoresis or immunoprecipitation demonstrates that the 50-kDa binding partner is itself EBP50, Further, co-transfection/co-precipitation studies show the self-association can occur in an intracellular environment, In vitro analysis of the EBP50-EBP50 binding interaction indicates it is both saturable and of relatively high affinity. Analysis of truncated EBP50 proteins indicates EBP50 self-association is mediated through its PDZ domains. The ability to self-associate provides a mechanism for EBP50 to expand its capacity to form multiprotein complexes and regulate membrane transport events.