STRUCTURAL STUDIES OF PHOSPHOINOSITIDE RELATED PROTEIN KINASES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 磷脂酰肌醇激酶相关蛋白激酶（PIKK）mTOR、ATM和ATR具有 重要的细胞功能。mTOR是PI 3 K/Akt信号传导中的中枢效应激酶 在人类癌症中经常失调的途径。ATM和ATR至关重要 DNA损伤信号通路中的细胞周期检查点激酶，保护细胞 防止DNA损伤和氧化应激。 针对mTOR的抑制剂目前在 临床癌症治疗试验。针对这些酶的其他选择性抑制剂可以 在实验室实验中有许多应用，并可能具有临床价值， 癌症的治疗 mTOR、ATM和ATR是分子量较大的蛋白质， 分别为288、350和300 kDa。它们含有保守的C-末端区域， 由FAT结构域、催化PIKK蛋白激酶结构域和FATC结构域组成。 所有三种蛋白质的催化结构域与以下蛋白质共享序列同源性： 磷酸肌醇激酶（PIK），如磷脂酰肌醇3-和4-激酶（PI 3 K， PI4K）。所有PIK和PIKK催化结构域均被小分子抑制剂抑制 渥曼青霉素，其与ATP结合位点结合。尽管功能的重要性 PIKK，目前只有一种I类PI 3 K的蛋白质结构可用作PIKK的模板。 这个酶家族 在这里，我们建议确定X射线晶体结构的 PIKs和PIKK的催化结构域，以研究酶促反应的结构基础。 催化和底物特异性。我们将检验所有家庭成员 含有结构上相关的ATP结合位点，其以类似的 PI 3 K和PI 4K的底物结合位点在结构上与 而PIKK的底物结合位点是不相关的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The phosphoinositide kinase related protein kinases (PIKK) mTOR, ATM and ATR have crucial cellular functions. mTOR is a central effector kinase in the PI3K/Akt signaling pathway that is frequently dysregulated in human cancers. ATM and ATR are essential cell cycle checkpoint kinases in the DNA damage signaling pathway, protecting cells against DNA damage and oxidative stress. Inhibitors against mTOR are currently in clinical cancer therapy trials. Additional selective inhibitors against these enzymes could have numerous applications in laboratory experiments and might be of clinical value for the treatment of cancer. mTOR, ATM and ATR are large proteins with molecular weights of 288, 350, and 300kDa, respectively. They contain a conserved C-terminal region, consisting of a FAT domain, a catalytic PIKK protein kinase domain and a FATC domain. The catalytic domain of all three proteins shares sequence homology with phosphoinositide kinases (PIK), such as phosphatidylinositol 3- and 4kinases (PI3K, PI4K). All PIK and PIKK catalytic domains are inhibited by the small-molecule inhibitor wortmannin, which binds to the ATP binding site. Despite the functional importance of PIKKs, only one protein structure of class I PI3K is currently available as a template for this enzyme family. Here, we propose to determine X-ray crystal structures of the catalytic domains of PIKs and PIKKs to investigate the structural basis of enzymatic catalysis and substrate specificity. We will test the hypothesis that all family members contain a structurally related ATP binding site that binds wortmannin in a similar position, and that the substrate-binding site of PI3K and PI4K is structurally related to each other, whereas the substrate-binding site of the PIKKs is unrelated.