SPOP介导的PDK1泛素化降解通过负调控PI3K/Akt通路抑制前列腺癌发生的机制研究

蛋白激酶PDK1作为AGC蛋白激酶家族重要成员之一，在调控细胞生存、增殖和代谢稳态过程中起着重要的作用。尽管PDK1通过磷酸化下游多种激酶如Akt，S6K和SGK参与肿瘤的调控已多有报道，然而有关PDK1的上游调控机制，尤其是其降解机制尚不清晰。我们通过筛选CRISPR-E3泛素化酶文库,发现SPOP是介导PDK1泛素化并降解的潜在E3泛素酶。进一步实验发现SPOP泛素化降解PDK1还可能依赖于CK1/GSK3β对PDK1的磷酸化,但其具体机制仍不清晰。因此，本课题旨在此研究基础上，进一步证实SPOP是降解PDK1的特异性E3泛素连接酶，并阐明其作用分子机制；明确CK1/GSK3β磷酸化PDK1在SPOP降解PDK1中的关键作用；探讨SPOP泛素化降解PDK1在调控Akt激酶活性及对前列腺癌发生、发展的重要作用。最终为针对前列腺癌的治疗提供有效的理论依据和潜在治疗方案。

PDK1 acts as a master kinase of AGC kinase members to physiopathologically govern cell survival, proliferation, and metabolic homeostasis. Although the regulation of its downstream substrates such as AKT and S6K have been well established, the upstream regulators of PDK1, especially its degrader, is not defined yet. Via a CRISPR-based E3 ligase screening approach, we identify that SPOP is a potential E3 ligase that mediates PDK1 ubiquitination and degradation. Specifically, SPOP degrades PDK1 may in CKI/GSK3beta phosphorylation dependent manners, however, the mechanism is not defined yet. Therefore, SPOP as a specific E3 ubiquitin ligase to degrade PDK1 needs further confirm. We propose to uncover the crucial role of CK1/GSK3beta in SPOP-mediated PDK1 degradation. And to explore the important role of SPOP-mediated PDK1 degradation in the regulation of Akt kinase activity, as well as in the occurrence and development of prostate cancer. Thus highlight a potential strategy for the treatment of prostate cancer.