PHOSPHATIDYLINOSITOL KINASE

由这笔赠款支持的以前的研究导致了 磷脂酰肌醇3-激酶(PI-3-Kinase)，并实现5 哺乳动物细胞中存在不同的磷脂酰肌醇(PtdIns-4-P，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AS 之前的想法是。在过去的授权期内，几个 制造这些脂质的酶的一部分已经被克隆，而这些酶 已被发现在许多细胞因子中扮演着意想不到的关键角色 功能。指导这一提议的假设是 特定亚型独有的Ptdins激酶允许独立控制 在细胞的不同隔间产生这些磷脂酰肌醇 出于不同的目的。这项提案的目标是比较 不同PtdIns激酶的结构及其结构域的剖析 赋予它们独特属性的结构。具体目标是 1)鉴定我们最近克隆的PtdIns 4-激酶，2)获得一个 与RAC结合的PtdIns-4-P5-Kinase的克隆，3)确定 PI-3-K、PtdIns-4-K和PtdIns-4-K相互作用的结构基础 PtdIns-4-P5-Kinase与细胞调节剂，4)确定结构 脂蛋白激酶活性的基础和意外蛋白激酶的基础 PI3-激酶的固有活性和5)决定酶活性 PI 3-激酶同系物家族的固有成分，包括最近的- 发现共济失调-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.