title: Role of membrane association and Atg14-dependent phosphorylation in beclin-1-mediated autophagy.
abstract: During autophagy, a double membrane envelops cellular material for trafficking to the lysosome. Human beclin-1 and its yeast homologue, Atg6/Vps30, are scaffold proteins bound in a lipid kinase complex with multiple cellular functions, including autophagy. Several different Atg6 complexes exist, with an autophagy-specific form containing Atg14. However, the roles of Atg14 and beclin-1 in the activation of this complex remain unclear. We here addressed the mechanism of beclin-1 complex activation and reveal two critical steps in this pathway. First, we identified a unique domain in beclin-1, conserved in the yeast homologue Atg6, which is involved in membrane association and, unexpectedly, controls autophagosome size and number in yeast. Second, we demonstrated that human Atg14 is critical in controlling an autophagy-dependent phosphorylation of beclin-1. We map these novel phosphorylation sites to serines 90 and 93 and demonstrate that phosphorylation at these sites is necessary for maximal autophagy. These results help clarify the mechanism of beclin-1 and Atg14 during autophagy.
authors.affiliation: Biochemistry Section, National Institute for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Adam I
authors.initials: AI
authors.lastname: Fogel
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Dlouhy
authors.forename: Chunxin
authors.initials: C
authors.lastname: Wang
authors.forename: Seung-Wook
authors.initials: SW
authors.lastname: Ryu
authors.forename: Albert
authors.initials: A
authors.lastname: Neutzner
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Hasson
authors.forename: Dionisia P
authors.initials: DP
authors.lastname: Sideris
authors.forename: Hagai
authors.initials: H
authors.lastname: Abeliovich
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Youle
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D051017:Apoptosis Regulatory Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000502:physiology*; D000071183:Autophagy-Related Proteins; D000071186:Beclin-1; D001665:Binding Sites; D002460:Cell Line; D055786:Gene Knockout Techniques; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010588:Phagosomes / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry
chemical_list: C539000:ATG14 protein, human; D033942:Adaptor Proteins, Vesicular Transport; D051017:Apoptosis Regulatory Proteins; D000071183:Autophagy-Related Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D012694:Serine