STRUCTURAL STUDIES OF PHOSPHOINOSITIDE RELATED PROTEIN KINASES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 磷脂酰肌醇激酶相关蛋白激酶(Pikk)mTOR、ATM和ATR有 关键的细胞功能。MTOR是PI3K/Akt信号通路中的中心效应蛋白 在人类癌症中经常失控的通路。ATM和ATR是必不可少的 DNA损伤信号通路中的细胞周期检查点激酶，保护细胞 对抗DNA损伤和氧化应激。针对mTOR的抑制剂目前正在开发中 癌症临床治疗试验。额外的选择性抑制这些酶的药物可能 在实验室实验中有许多应用，可能对临床有价值 癌症的治疗。MTOR、ATM和ATR是具有大分子量的蛋白质 分别为288 kDa、350 kDa和300 kDa。它们含有保守的C-末端区域， 由脂肪结构域、催化Pikk蛋白激酶结构域和FATC结构域组成。 这三种蛋白质的催化结构域都具有同源性 磷酸肌醇激酶(PIK)，如磷脂酰肌醇3-和4-激酶(PI3K， PI4K)。所有的PIK和PIKK催化结构域都被小分子抑制剂抑制 Wortmannin，它与ATP结合位点结合。尽管具有重要的功能，但 PIKK，目前只有一种I类PI3K的蛋白质结构可作为模板用于 这个酶家族。在这里，我们建议确定化合物的X射线晶体结构。 PIKs和PIKKs的催化结构域研究酶的结构基础 催化和底物专一性。我们将检验所有家庭成员的假设 含有与Wortmannin结合的结构相关的ATP结合位点 PI3K和PI4K的底物结合部位在结构上与 而PIKK的底物结合位点是无关的。

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.