MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510275, China.
Organ Transplant Center, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510080, China.
Cell Rep. 2020 Feb 25;30(8):2807-2819.e4. doi: 10.1016/j.celrep.2020.01.088.
The class III phosphoinositide 3-kinase vacuolar protein sorting 34 (VPS34) is a core protein of autophagy initiation, yet the regulatory mechanisms responsible for its stringent control remain poorly understood. Here, we report that the E3 ubiquitin ligase NEDD4-1 promotes the autophagy flux by targeting VPS34. NEDD4-1 undergoes lysine 29 (K29)-linked auto-ubiquitination at K1279 and serves as a scaffold for recruiting the ubiquitin-specific protease 13 (USP13) to form an NEDD4-1-USP13 deubiquitination complex, which subsequently stabilizes VPS34 to promote autophagy through removing the K48-linked poly-ubiquitin chains from VPS34 at K419. Knockout of either NEDD4-1 or USP13 increased K48-linked ubiquitination and degradation of VPS34, thus attenuating the formation of the autophagosome. Our results identify an essential role for NEDD4-1 in regulating autophagy, which provides molecular insights into the mechanisms by which ubiquitination regulates autophagy flux.
III 类磷酸肌醇 3-激酶液泡分选 34 蛋白（VPS34）是自噬起始的核心蛋白，但负责其严格控制的调节机制仍知之甚少。在这里，我们报告 E3 泛素连接酶 NEDD4-1 通过靶向 VPS34 促进自噬通量。NEDD4-1 在赖氨酸 1279 处发生赖氨酸 29（K29）连接的自身泛素化，并作为招募泛素特异性蛋白酶 13（USP13）形成 NEDD4-1-USP13 去泛素化复合物的支架，该复合物随后通过从 VPS34 的 K419 上去除 K48 连接的多泛素链来稳定 VPS34，从而通过去除 K48 连接的多泛素链来促进自噬。敲除 NEDD4-1 或 USP13 均会增加 VPS34 的 K48 连接泛素化和降解，从而减弱自噬体的形成。我们的结果确定了 NEDD4-1 在调节自噬中的重要作用，为泛素化如何调节自噬通量的机制提供了分子见解。
