Cul3-KLHL20 Ubiquitin Ligase Governs the Turnover of ULK1 and VPS34 Complexes to Control Autophagy Termination

Chin-Chih Liu; Yu-Ching Lin; Yu-Hsuan Chen; Chun-Ming Chen; Liang-Yu Pang; Hsuan-An Chen; Pei-Rung Wu; Mei-Yao Lin; Si-Tse Jiang; Ting-Fen Tsai; Ruey-Hwa Chen

doi:10.1016/j.molcel.2015.11.001

Cul3-KLHL20 Ubiquitin Ligase Governs the Turnover of ULK1 and VPS34 Complexes to Control Autophagy Termination

Mol Cell. 2016 Jan 7;61(1):84-97. doi: 10.1016/j.molcel.2015.11.001. Epub 2015 Dec 10.

Authors

Affiliations

¹ Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei 106, Taiwan.
² Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan.
³ Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
⁴ Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
⁵ Department of Life Sciences and Institute of Genome Sciences, National Yang Ming University, Taipei 112, Taiwan.
⁶ Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei 106, Taiwan; Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan. Electronic address: rhchen@gate.sinica.edu.tw.

PMID: 26687681
DOI: 10.1016/j.molcel.2015.11.001

Abstract

Autophagy, a cellular self-eating mechanism, is important for maintaining cell survival and tissue homeostasis in various stressed conditions. Although the molecular mechanism of autophagy induction has been well studied, how cells terminate autophagy process remains elusive. Here, we show that ULK1, a serine/threonine kinase critical for autophagy initiation, is a substrate of the Cul3-KLHL20 ubiquitin ligase. Upon autophagy induction, ULK1 autophosphorylation facilitates its recruitment to KLHL20 for ubiquitination and proteolysis. This autophagy-stimulated, KLHL20-dependent ULK1 degradation restrains the amplitude and duration of autophagy. Additionally, KLHL20 governs the degradation of ATG13, VPS34, Beclin-1, and ATG14 in prolonged starvation through a direct or indirect mechanism. Impairment of KLHL20-mediated regulation of autophagy dynamics potentiates starvation-induced cell death and aggravates diabetes-associated muscle atrophy. Our study identifies a key role of KLHL20 in autophagy termination by controlling autophagy-dependent turnover of ULK1 and VPS34 complex subunits and reveals the pathophysiological functions of this autophagy termination mechanism.

Keywords: ULK1; VPS34 complex; autophagy; ubiquitination.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport / metabolism
Animals
Apoptosis Regulatory Proteins / metabolism
Autophagy*
Autophagy-Related Protein-1 Homolog
Autophagy-Related Proteins
Beclin-1
Carrier Proteins / genetics
Carrier Proteins / metabolism*
Class III Phosphatidylinositol 3-Kinases / genetics
Class III Phosphatidylinositol 3-Kinases / metabolism*
Cullin Proteins / genetics
Cullin Proteins / metabolism*
Diabetes Complications / enzymology
Diabetes Complications / genetics
Diabetes Complications / pathology
Feedback, Physiological
HEK293 Cells
HeLa Cells
Humans
Intracellular Signaling Peptides and Proteins / genetics
Intracellular Signaling Peptides and Proteins / metabolism*
Male
Membrane Proteins / metabolism
Mice, Inbred C57BL
Mice, Knockout
Muscle, Skeletal / enzymology
Muscle, Skeletal / pathology
Muscular Atrophy / enzymology
Muscular Atrophy / genetics
Muscular Atrophy / pathology
Phosphorylation
Protein Serine-Threonine Kinases / genetics
Protein Serine-Threonine Kinases / metabolism*
Protein Transport
Proteolysis
RNA Interference
Signal Transduction
Time Factors
Transfection
Ubiquitin-Protein Ligases / deficiency
Ubiquitin-Protein Ligases / genetics
Ubiquitin-Protein Ligases / metabolism*
Ubiquitination
Vesicular Transport Proteins / metabolism

Substances

ATG14 protein, human
Adaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport
Apoptosis Regulatory Proteins
Atg14 protein, mouse
Autophagy-Related Proteins
BECN1 protein, human
Beclin-1
Becn1 protein, mouse
CUL3 protein, human
Carrier Proteins
Cul3 protein, mouse
Cullin Proteins
Intracellular Signaling Peptides and Proteins
KLHL20 protein, human
KLHL20 protein, mouse
Membrane Proteins
Vesicular Transport Proteins
Ubiquitin-Protein Ligases
Class III Phosphatidylinositol 3-Kinases
Autophagy-Related Protein-1 Homolog
Protein Serine-Threonine Kinases
ULK1 protein, human
Ulk1 protein, mouse