Structural studies of ubiquitin-like protein modification

描述(申请人提供)：信号转导通路依靠可逆的化学修饰在细胞内和细胞间传递信息。泛素和泛素样蛋白如SUMO(小泛素样修饰物)对蛋白质底物的共价修饰有助于调节细胞功能，包括核运输、胞质分裂、染色体分离、G2-M细胞周期进展和转录调节等。泛素(Ub)和类泛素(Ubl)蛋白的翻译后修饰需要E1激活酶、E2结合酶和E3连接酶的顺序作用，而Ub/Ub1的加工和去结合是由Ub/Ubl特异性的酶催化的。泛素和相扑结合在真核细胞的核代谢和细胞周期控制中起着不可或缺的作用，我们的研究直接关系到人类健康、癌症和美国国立卫生研究院的使命。这项建议试图通过结构、生化和遗传学研究来解决泛素和相扑结合途径组件的功能意义，这些研究将为Ub/Ub1激活，2)E2和E3酶的结合，3)通过识别Ub/Ub1结合底物的表征受体进行信号转导奠定基础。组成泛素和相扑蛋白结合途径的酶、机制和因素是保守的，因此我们的研究将具有广泛的相关性，并将影响其他Ub/Ub1相关途径的研究。

DESCRIPTION (provided by applicant): Signal transduction pathways rely on reversible chemical modifications to relay information within and across cells. Covalent modification of protein substrates by ubiquitin and the ubiquitin-like proteins such as SUMO (small ubiquitin-like modifier) contribute to pathways that regulate cellular functions including nuclear transport, cytokinesis, chromosome segregation, G2-M cell cycle progression and transcriptional regulation among many others. Post-translational modification by ubiquitin (Ub) and ubiquitin-like (Ubl) proteins requires the sequential action of E1 activating enzymes, E2 conjugating enzymes and E3 ligases while Ub/Ubl processing and deconjugation is catalyzed by Ub/Ubl-specific proteases. Ubiquitin and SUMO conjugation play an integral role in eukaryotic nuclear metabolism and cell cycle control and our studies are of direct relevance to human health, cancer, and the mission of the NIH. This proposal seeks to address the functional significance for components of the ubiquitin and SUMO conjugation pathways through structural, biochemical and genetic studies that will establish the basis for Ub/Ubl 1) activation, 2) conjugation by E2 and E3 enzymes, 3) signal transduction through characterization receptors that recognize Ub/Ubl-conjugated substrates. The enzymes, mechanisms and factors that constitute ubiquitin and SUMO protein conjugation pathways are conserved so our studies will be broadly relevant and will impact research in other Ub/Ubl-related pathways.