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

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.

• Authors: Yonghua Yang, Warren Fiskus, Bao Yong, Peter Atadja, Yoshinori Takahashi, Tej K Pandita, Hong-Gang Wang, Kapil N Bhalla
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 110 Issue 17 Pg. 6841-6 (Apr 23 2013) ISSN: 1091-6490 [Electronic] United States
• PMID: 23569248 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• 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

Topics

• 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, metabolism)
• Humans
• Immunoblotting
• Immunoprecipitation
• MCF-7 Cells
• Mass Spectrometry
• Mice
• Mice, Knockout
• Microscopy, Fluorescence
• Multiprotein Complexes (metabolism)
• Nuclear Proteins (metabolism)
• Phagosomes (metabolism, physiology)
• Repressor Proteins (metabolism)
• Sumoylation
• Tripartite Motif-Containing Protein 28