title: AMPK-dependent phosphorylation of ULK1 regulates ATG9 localization.
abstract: Autophagy is activated in response to a variety of cellular stresses including metabolic stress. While elegant genetic studies in yeast have identified the core autophagy machinery, the signaling pathways that regulate this process are less understood. AMPK is an energy sensing kinase and several studies have suggested that AMPK is required for autophagy. The biochemical connections between AMPK and autophagy, however, have not been elucidated. In this report, we identify a biochemical connection between a critical regulator of autophagy, ULK1, and the energy sensing kinase, AMPK. ULK1 forms a complex with AMPK, and AMPK activation results in ULK1 phosphorylation. Moreover, we demonstrate that the immediate effect of AMPK-dependent phosphorylation of ULK1 results in enhanced binding of the adaptor protein YWHAZ/14-3-3ζ; and this binding alters ULK1 phosphorylation in vitro. Finally, we provide evidence that both AMPK and ULK1 regulate localization of a critical component of the phagophore, ATG9, and that some of the AMPK phosphorylation sites on ULK1 are important for regulating ATG9 localization. Taken together these data identify an ULK1-AMPK signaling cassette involved in regulation of the autophagy machinery.
authors.affiliation: Cancer Biology Program, Division of Hematology/Oncology, Department of Medicine Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors.forename: Hildegard I D
authors.initials: HI
authors.lastname: Mack
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.forename: John M
authors.initials: JM
authors.lastname: Asara
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Thomas
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism; D055372:AMP-Activated Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000071189:Autophagy-Related Protein-1 Homolog; D000071183:Autophagy-Related Proteins; D020134:Catalytic Domain; D004622:Embryo, Mammalian / Q000166:cytology; D004789:Enzyme Activation; D005347:Fibroblasts / Q000201:enzymology; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D055550:Protein Stability; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport; D015398:Signal Transduction; D013312:Stress, Physiological; D051758:Transcription Factor TFIIH; D014157:Transcription Factors; D033921:Vesicular Transport Proteins
chemical_list: D048948:14-3-3 Proteins; C549015:Atg9A protein, mouse; D000071183:Autophagy-Related Proteins; C490981:Gtf2h1 protein, mouse; D008565:Membrane Proteins; D021122:Protein Subunits; D014157:Transcription Factors; D033921:Vesicular Transport Proteins; D010769:Phosphothreonine; D051758:Transcription Factor TFIIH; D010768:Phosphoserine; C401061:Ulk2 protein, mouse; D000071189:Autophagy-Related Protein-1 Homolog; D017346:Protein Serine-Threonine Kinases; C112444:Ulk1 protein, mouse; D055372:AMP-Activated Protein Kinases