Regulation of mATG9 trafficking by Src- and ULK1mediated phosphorylation in basal and starvation-induced autophagy

• Published in: 细胞研究：英文版 Vol. 27; no. 2; pp. 184 - 201
• Main Author: Changqian Zhou Kaili Ma Ruize Gao Chenglong Mu Linbo Chen Qiangqiang Liu Qian Luo Du Feng Yushan Zhu Quan Chen
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Src; 基底; 相互作用; 磷酸化; 自噬作用; 诱导; 贩运; 饥饿
• ISSN: 1001-0602

Autophagy requires diverse membrane sources and involves membrane trafficking of mATG9, the only membrane protein in the ATG family. However, the molecular regulation of mATG9 trafficking for autophagy initiation remains unclear. Here we identified two conserved classic adaptor protein sorting signals within the cytosolic N-terminus of mATG9, which mediate trafficking of mATG9 from the plasma membrane and trans-Golgi network （TGN） via interaction with the AP1/2 complex. Src phosphorylates mATG9 at Tyr8 to maintain its endocytic and constitutive trafficking in unstressed conditions. In response to starvation, phosphorylation of mATG9 at Tyr8 by Sre and at Serl4 by ULK1 functionally cooperate to promote interactions between mATG9 and the AP1/2 complex, leading to redistribution of mATG9 from the plasma membrane and juxta-nuclear region to the peripheral pool for autophagy initiation. Our findings uncover novel mechanisms of mATG9 trafficking and suggest a coordination of basal and stress-induced autophagy.