Acetylation of STX17 (syntaxin 17) controls autophagosome maturation

Qiuhong Shen; Yin Shi; Jiaqi Liu; Hua Su; Jingtao Huang; Yi Zhang; Chao Peng; Tianhua Zhou; Qiming Sun; Wei Wan; Wei Liu

doi:10.1080/15548627.2020.1752471

Acetylation of STX17 (syntaxin 17) controls autophagosome maturation

Autophagy. 2021 May;17(5):1157-1169. doi: 10.1080/15548627.2020.1752471. Epub 2020 Apr 15.

Authors

Qiuhong Shen¹, Yin Shi¹, Jiaqi Liu¹, Hua Su¹, Jingtao Huang¹, Yi Zhang¹, Chao Peng², Tianhua Zhou¹, Qiming Sun¹, Wei Wan³, Wei Liu^{1

4}

Affiliations

¹ Department of Biochemistry and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
² National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
³ Department of Biochemistry and Department of Thoracic Surgery of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.
⁴ Zhejiang University School of Medicine, Joint Institute of Genetics and Genomics Medicine between Zhejiang University and University of Toronto, Hangzhou, China.

Abstract

The fusion of autophagosomes and endosomes/lysosomes, also called autophagosome maturation, ensures the degradation of autophagic cargoes. It is an important regulatory step of the macroautophagy/autophagy process. STX17 is the key autophagosomal SNARE protein that mediates autophagosome maturation. Here, we report that the acetylation of STX17 regulates its SNARE activity and autophagic degradation. The histone acetyltransferase CREBBP/CBP and the deacetylase HDAC2 specifically regulate the acetylation of STX17. In response to cell starvation and MTORC1 inhibition, the inactivation of CREBBP leads to the deacetylation of STX17 at its SNARE domain. This deacetylation promotes the interaction between STX17 and SNAP29 and the formation of the STX17-SNAP29-VAMP8 SNARE complex with no effect on the recruitment of STX17 to autophagosomal membranes. Deacetylation of STX17 also enhances the interaction between STX17 and the tethering complex HOPS, thereby further promoting autophagosome-lysosome fusion. Our study suggests a mechanism by which acetylation regulates the late-stage of autophagy, and possibly other STX17-related intracellular membrane fusion events.Abbreviations: ACTB: actin beta; CREBBP/CBP: CREB binding protein; Ctrl: control; GFP: green fluorescent protein; GST: glutathione S-transferase; HDAC: histone deacetylase; HOPS: homotypic fusion and protein sorting complex; KO: knockout; LAMP1/2: lysosomal associated membrane protein 1/2; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MEFs: mouse embryonic fibroblasts; MS: mass spectrometry; MTORC1: mechanistic target of rapamycin kinase complex 1; NAM: nicotinamide; PtdIns3K: phosphatidylinositol 3-kinase; RFP: red fluorescent protein; SNAP29: synaptosome associated protein 29; SNARE: soluble N-ethylamide-sensitive factor attachment protein receptor; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TSA: trichostatin A; TSC1/2: TSC complex subunit 1/2; VAMP8: vesicle associated membrane protein 8; WT: wild type.

Keywords: Acetylation; CREBBP; HDAC2; HOPS; STX17; autophagosome maturation.

Publication types

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

MeSH terms

Autophagosomes / metabolism*
Autophagy / physiology*
Endosomes / metabolism
Fibroblasts / metabolism
Humans
Lysosomes / metabolism
Macroautophagy / physiology*
Membrane Fusion / physiology
Qa-SNARE Proteins / metabolism*

Substances

Qa-SNARE Proteins
STX17 protein, human

Grants and funding

This study was supported by the National Basic Research Program of China [2017YFA0503402] and the National Natural Science Foundation of China [31790402, 31530040, and 31671434].