PHOSPHATIDYLINOSITOL KINASE

此前由该基金支持的研究发现了 磷脂酰肌醇3-激酶（PI 3-激酶），并实现五个 在哺乳动物细胞中存在不同的磷酸肌醇（PtdIns-4-P，PtdIns-4- P、Ptdins-3，4-P2、Ptdins-4，5-P2和Ptdins-3，4，5-P3），而不是两个作为 以前认为。在过去的授权期间，几个cDNA克隆 制造这些脂质的酶已经被克隆， 在许多细胞中发挥着意想不到的关键作用， 功能协调发展的指导这一建议的假设是， Ptdins激酶是特异性同种型所特有的， 在细胞的不同区室产生这些磷酸肌醇 有不同的目的本提案的目的是比较 不同PtdIns激酶的结构，并剖析结构域 这些结构赋予了它们独特的性质。具体目标是 1)表征我们最近克隆的PtdIns 4-激酶，2）获得cDNA 与rac缔合的PtdIns-4-P5-激酶的克隆，3）确定 PI 3-激酶、PtdIns 4-激酶和 PtdIns-4-P5-激酶与细胞调节剂，4）确定结构 脂质激酶活性和一种意想不到的蛋白激酶的基础 PI 3-激酶固有的活性和5）确定酶活性 PI 3-激酶同源物家族的固有特性，包括最近的- 发现了共济失调-毛细血管扩张症基因。

Previous research supported by this grant led to the discovery of phosphoinositide 3-kinase (PI 3-kinase), and the realization that five different phosphoinositides exist in mammalian cells (PtdIns-4-P, PtdIns-4- P, Ptdins-3,4-P2, Ptdins-4,5-P2 and Ptdins-3,4,5-P3) rather than two as previously thought. During the past granting period, cDNA clones of several of the enzymes that make these lipids have been cloned and these enzymes have been found to play unexpected critical roles in a host of cellular functions. The hypothesis guiding this proposal is that subdomains of the Ptdins kinases unique to specific isoforms allow independent control of production of these phosphoinositides at distinct compartments of the cell for distinct purposes. The goal of this proposal is to compare the structures of the different PtdIns kinases and dissect the domain structures that give them their unique properties. The specific aims are to 1) characterize a PtdIns 4-kinase we recently cloned, 2) obtain a cDNA clone of a PtdIns-4-P 5-kinase that associates with rac, 3) determine the structural basis for association of PI 3- kinase, PtdIns 4-kinase and PtdIns-4-P 5-kinase with cellular regulators, 4) determine the structural basis for lipid kinase activity and for an unexpected protein kinase activity intrinsic to PI 3-kinase and 5) determine the enzymatic activities intrinsic to a family of PI 3-kinase homologues that includes the recently- discovered Ataxia-Telangiectasia gene.