title: Atg29 phosphorylation regulates coordination of the Atg17-Atg31-Atg29 complex with the Atg11 scaffold during autophagy initiation.
abstract: Macroautophagy (hereafter autophagy) functions in the nonselective clearance of cytoplasm. This process participates in many aspects of cell physiology, and is conserved in all eukaryotes. Autophagy begins with the organization of the phagophore assembly site (PAS), where most of the AuTophaGy-related (Atg) proteins are at least transiently localized. Autophagy occurs at a basal level and can be induced by various types of stress; the process must be tightly regulated because insufficient or excessive autophagy can be deleterious. A complex composed of Atg17-Atg31-Atg29 is vital for PAS organization and autophagy induction, implying a significant role in autophagy regulation. In this study, we demonstrate that Atg29 is a phosphorylated protein and that this modification is critical to its function; alanine substitution at the phosphorylation sites blocks its interaction with the scaffold protein Atg11 and its ability to facilitate assembly of the PAS. Atg29 has the characteristics of an intrinsically disordered protein, suggesting that it undergoes dynamic conformational changes on interaction with a binding partner(s). Finally, single-particle electron microscopy analysis of the Atg17-Atg31-Atg29 complex reveals an elongated structure with Atg29 located at the opposing ends.
authors.affiliation: Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Mao
authors.forename: Leon H
authors.initials: LH
authors.lastname: Chew
authors.forename: Yuko
authors.initials: Y
authors.lastname: Inoue-Aono
authors.forename: Heesun
authors.initials: H
authors.lastname: Cheong
authors.forename: Usha
authors.initials: U
authors.lastname: Nair
authors.forename: Hana
authors.initials: H
authors.lastname: Popelka
authors.forename: Calvin K
authors.initials: CK
authors.lastname: Yip
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Klionsky
mesh_terms: D001343:Autophagy / Q000502:physiology*; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D010766:Phosphorylation / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C506770:ATG29 protein, S cerevisiae; C502923:Atg11 protein, S cerevisiae; C505602:Atg17 protein, S cerevisiae; C520043:Atg31 protein, S cerevisiae; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins
keywords: lysosome; organelle biogenesis; vacuole; yeast