GSK3-TIP60-ULK1 signaling pathway links growth factor deprivation to autophagy.
In metazoans, cells depend on extracellular growth factors for energy homeostasis. We found that glycogen synthase kinase-3 (GSK3), when deinhibited by default in cells deprived of growth factors, activates acetyltransferase TIP60 through phosphorylating TIP60-Ser(86), which directly acetylates and stimulates the protein kinase ULK1, which is required for autophagy. Cells engineered to express TIP60(S86A) that cannot be phosphorylated by GSK3 could not undergo serum deprivation-induced autophagy. An acetylation-defective mutant of ULK1 failed to rescue autophagy in ULK1(-/-) mouse embryonic fibroblasts. Cells used signaling from GSK3 to TIP60 and ULK1 to regulate autophagy when deprived of serum but not glucose. These findings uncover an activating pathway that integrates protein phosphorylation and acetylation to connect growth factor deprivation to autophagy.
State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Fujian, China.
SourceScience (New York, N.Y.) 336:6080 2012 Apr 27 pg 477-81
Cell Line, Tumor
Culture Media, Serum-Free
Glycogen Synthase Kinase 3
Intercellular Signaling Peptides and Proteins
Intracellular Signaling Peptides and Proteins
Pub Type(s)Journal Article
Research Support, Non-U.S. Gov't