Acetylated hsp70 and KAP1-mediated Vps34 SUMOylation is required for autophagosome creation in autophagy

Proc Natl Acad Sci U S A. 2013 Apr 23;110(17):6841-6. doi: 10.1073/pnas.1217692110. Epub 2013 Apr 8.

Abstract

Autophagy is a stress-induced catabolic process in which cytoplasmic components, sequestered in double-membrane autophagic vesicles (AVs) or autophagosomes, are delivered to lysosomes for degradation and recycling [Kroemer G, Mariño G, Levine B (2010) Mol Cell 40(2):280-293]. Activity of the class III phosphatidylinositol-3-OH-kinase (PI3K) vacuolar protein-sorting (Vps) 34, bound to coiled-coil moesin-like B-cell lymphoma 2 (Bcl-2)-interacting protein Beclin-1, is required for phosphoinositide generation, essential for AV formation in autophagy [Cuervo AM (2010) Nat Cell Biol 12(8):735-737]. However, how autophagy-inducing stress regulates Vps34 activity has not been fully elucidated. Our findings demonstrate that autophagy-inducing stress increases intracellular levels of acetylated inducible heat shock protein (hsp) 70, which binds to the Beclin-1-Vps34 complex. Acetylated hsp70 also recruits E3 ligase for SUMOylation, KRAB-ZFP-associated protein 1 (KAP1), inducing Lys840 SUMOylation and increasing Vps34 activity bound to Beclin 1. Knockdown of hsp70 abolished the Beclin-1-Vps34 complex formation, as well as inhibited KAP1 binding to Vps34 and AV formation. Notably, autophagy-inducing stress due to histone deacetylase inhibitor treatment induced AV formation in the wild-type but not hsp70.1/3 knockout mouse embryonic fibroblasts MEFs. These findings highlight a regulatory mechanism of Vps34 activity, which involves acetylated hsp70 and KAP1-dependent SUMOylation of Vps34 bound to Beclin 1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Animals
  • Apoptosis Regulatory Proteins / metabolism
  • Autophagy / physiology*
  • Beclin-1
  • Class III Phosphatidylinositol 3-Kinases / metabolism*
  • Genetic Vectors / genetics
  • HEK293 Cells
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism*
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • MCF-7 Cells
  • Mass Spectrometry
  • Mice
  • Mice, Knockout
  • Microscopy, Fluorescence
  • Multiprotein Complexes / metabolism*
  • Nuclear Proteins / metabolism*
  • Phagosomes / metabolism*
  • Phagosomes / physiology
  • Repressor Proteins / metabolism*
  • Sumoylation
  • Tripartite Motif-Containing Protein 28

Substances

  • Apoptosis Regulatory Proteins
  • Beclin-1
  • Becn1 protein, mouse
  • HSP70 Heat-Shock Proteins
  • Multiprotein Complexes
  • Nuclear Proteins
  • Repressor Proteins
  • Trim28 protein, mouse
  • Tripartite Motif-Containing Protein 28
  • Class III Phosphatidylinositol 3-Kinases