蛋白复合体PWP1-MYBBP1A参与TORC1调控生长机制的研究

Protein kinase TORC1 is the primary mediator of animal growth, which integrates signals from amino acids and energy sensing with those of systemic hormones. The main mechanism by which TORC1 drives growth is by adjusting protein biosynthesis and gene expression to accumulate cellular mass. As a consequence TORC1 is hyperactivated in almost all cancers. Here we propose to explore the function of a novel protein complex including nuclear protein PWP1 and a transcriptional cofactor MYBBP1A. The role of this complex in growth control likely through phosphorylation by TORC1 was recently discovered by us in Drosophila. In the proposed project, we aim to achieve mechanistic understanding into the regulatory interrelationship between TORC1 and this complex via phosphorylation sites and genetic analyses performed in Drosophila. In addition, we also propose to utilize genetic loss of function in Drosophila to identify targets of this complex by TORC1 involved in ribosome biogenesis and tissue growth. In sum, the proposed project should reveal the regulation between TORC1 and PWP1-MYBBP1A complex, uncover their downstream effectors relevant for animal growth as well as provide insight into therapeutics to treat diseases related to TORC1.

蛋白激酶TORC1是动物生长调控的核心因子，它响应细胞内的氨基酸和能量水平，以及整个动物体的激素信号，通过调节蛋白合成和基因表达来促进细胞生长。因此TORC1的活性过高往往会导致细胞生长失控形成肿瘤。本项目提出研究一个新的由核蛋白PWP1和转录辅助因子MYBPP1A组成的蛋白复合体。项目组最近在果蝇中发现该复合体受TORC1磷酸化修饰，参与组织生长，但具体机制不明。本项目计划通过磷酸化位点研究和果蝇遗传分析进一步证明TORC1和该复合体间的调节关系和机制。同时，本项目还计划通过该复合体的突变果蝇找出其下游参与TORC1引导的核糖体生成和细胞生长的靶目标。本项目的研究将阐明TORC1和PWP1-MYBBP1A复合体之间的调控关系，揭示它们下游与动物生长相关的作用机制，为TORC1相关疾病的治疗奠定基础。

蛋白激酶TORC1是调控动物生长代谢的核心因子。它响应胰岛素信号，通过调节核糖体生成和基因转录来促进组织生长和能量代谢。本项目前期发现一个由核蛋白PWP1和转录辅助因子MYBBP1A组成的蛋白复合体。在果蝇中敲降该复合体影响个体生长，且复合体中PWP1蛋白的磷酸化水平受TORC1活性影响。为了阐明TORC1与PWP1-MYBBP1A互作可能调控生长的机制，本研究首先通过基因敲除果蝇的PWP1和MYBBP1A，验证了它们的生长表型与缺失TORC1的相似度。同时通过敲降TORC1组成蛋白Raptor而非下游激酶S6K影响PWP1的磷酸化，证明了TORC1直接修饰PWP1，并揭示该修饰发生在S384位点上。接着，项目组通过组织特异性敲降表达调控，进一步证明了胰岛素/TORC1通过PWP1-MYBBP1A影响果蝇生长的遗传互作关系。然后本研究通过分析PWP1和MYBBP1A突变体的rRNA和转录组，从分子层面再次证明了TORC1与PWP1-MYBBP1A的相似性，并深入探讨了它们下游共同靶基因Bigmax，研究了Bigmax与TORC1/PWP1/MYBBP1A相关的生长和衰老代谢表型。这些结果表明了TORC1和PWP1-MYBBP1A的调控关系，以及它们下游与动物生长代谢相关的作用机制。