P300/HDAC1 regulates the acetylation/deacetylation and autophagic activities of LC3/Atg8\u2013PE ubiquitin-like system

Wenmei Wu,Shuyan Li,Qiuqin Ma,Sheng Li,Yang Cao,Sanyou Guo,Zhijun Huang,Ling Tian,Xianying Xu,Jing Xu,Yangjin Zhong,Gianluca Tettamanti,Kang Li

doi:10.1038/s41420-021-00513-0

Abstract

Protein acetylation plays potential roles in regulating autophagy occurrence. However, it varies greatly between yeast and mammals, and has not been thoroughly investigated in other organisms. Here, we reported that the components of BmAtg8–PE ubiquitin-like system (BmAtg3, BmAtg4, BmAtg7, and BmAtg8) in Bombyx mori were localized in the nucleus under nutrient-rich conditions, whereas they were exported to the cytoplasm upon autophagy induction. RNAi of BmP300 and inhibition of BmP300 activity resulted in nucleo-cytoplasmic translocation of BmAtg3 and BmAtg8, as well as premature induction of autophagy in the absence of stimulus. Conversely, RNAi of BmHDAC1 and inhibition of class I/II HADCs activities led to the nuclear accumulation of BmAtg3 and BmAtg8. In addition, acetylation sites in Atg proteins of BmAtg8–PE ubiquitin-like system were identified by mass spectrometry, and acetylation-site mutations caused nucleo-cytoplasmic translocation of BmAtg3, BmAtg4, and BmAtg8 along with autophagy promotion. Similarly, the subcellular localization of human ATG4b is determined by acetylation modification. In general, BmP300-mediated acetylation sequesters the components of BmAtg8–PE ubiquitin-like system in the nucleus, thus leading to the autophagy inhibition. Oppositely, BmHDAC1-mediated deacetylation leads to the nucleo-cytoplasmic translocation of the components of BmAtg8–PE ubiquitin-like system and promotes autophagy. This process is evolutionarily conserved between insects and mammals.

Highlights

Macroautophagy/autophagy, which is implicated in neurodegenerative diseases, tumorigenesis, and pathogen invasion, is a finely regulated cellular process for bulk degradation of cellular components[1]
Regulation of autophagy by acetylation/deacetylation is evolutionarily conserved between insects and mammals As introduced at the beginning, acetylation/deacetylation of the Atg8–PE ubiquitin-like system displays controversial function in autophagy regulation in yeast and mammals
We demonstrate that the components of BmAtg8–PE ubiquitin-like system are necessary for BmAtg8–PE conjugation and autophagy induction in B. mori

Summary

Introduction

Macroautophagy/autophagy, which is implicated in neurodegenerative diseases, tumorigenesis, and pathogen invasion, is a finely regulated cellular process for bulk degradation of cellular components[1]. Atg[4] is the sole cysteine protease responsible for the cleavage of nascent LC3/Atg[83]. After exposure of the C-terminal, LC3/Atg[8] is adenylated by the. E1-like enzyme Atg[7] to form a covalent thioester-linked intermediate, and is transferred to E2-like enzyme Atg[3] before conjugation with PE2,4,5. There are four Atg[4] genes in mammals, one in yeast, two in Caenorhabditis elegans and Drosophila melanogaster, respectively[2,6]. The protease activity of different ATG4 to different LC3 homologs is notably varied[7,8]. Mammalian ATG4b cleaves most LC3 homologs, and is considered as a potential biomarker and therapeutic target in human diseases[9,10]

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