PH结构域的结构和功能研究进展

Structure and Function of PH Domain

ＰＨ结构域是一种存在于多种信号转导蛋白和细胞骨架蛋白中的大约由１２０个氨基酸组成的功能性区域．不同蛋白质中的ＰＨ结构域在一级结构上的同源性并不很高，但其空间结构中肽链主链的折叠方式基本相同，而主要差别存在于其中的三个可变环上，含有这些环的侧面带有正电荷，被认为可能是其配体的结合部位．目前已知的配体有Ｇ蛋白βγ亚单位（Ｇβγ）、蛋白激酶Ｃ（ＰＫＣ）和磷脂酰肌醇衍生物（ＰＩＰ２或ＩＰ３），所以ＰＨ结构域可能介导信号蛋白与这些分子间的相互作用，参与细胞信号转导网络的构成．

The PH domain is a protein module of approximately 120 amino acid residues founded in many proteins involved in signal transduction. The PH domains are similar to each other in their threedimentional structures,and the major structure difference among them lies in the three variable loops in the structures. The PH domain is electrostaticallypolarized and the variable loops are on the positivelycharged surface, which may serve as a ligandbinding surface. So far ,it has been found that PH domains can interact with the βγsubunits of G protein (Gβγ)、protein kinase C (PKC) and phosphatidylinositol-4,5-bisphosphate (PIP-2 or inositol-1,4,5-trisphosphate (IP 3)). All these implied that PH domain might play an important role in the interaction between the signaling molecules and help to form the signal transduction network.