Transcription and Post-translational Regulation of Autophagy in Insects.

Rongsong Li,Kang Li,Yang Xiao,Ling Tian

doi:10.3389/fphys.2022.825202

Abstract

Autophagy attracts great attention, and numerous progresses have been obtained in the last two decades. Autophagy is implicated in mammalian neurodegenerative diseases, tumorigenesis, as well as development in insects. The regulatory mechanism of autophagy is well documented in yeast and mammals, whereas it is not fully illustrated in insects. Drosophila melanogaster and Bombyx mori are the two well-studied insects for autophagy, and several insect-mammalian evolutionarily conserved or insect-specific mechanisms in regulating autophagy are reported. In this review, we summarize the most recent studies of autophagy regulated at both transcriptional and post-translational levels by insect hormone in cooperation with other signals, such as nutrient, which will provide a reference and deep thinking for studies on autophagy in insects.

Highlights

Macroautophagy, hereafter referred to as autophagy, is a self-eating process to recycle intracellular components and extensively exists in organisms under physiological and pathophysiological conditions (Klionsky et al, 2021)
Some of them are functionally conserved to the mammalian homologs, while some of them act in insects . 20E, the insect-specific regulator, predominantly upregulates autophagy by inducing the expression of almost all Atg genes directly; in addition, 20E signaling interacts with other transcription factors, such as FOXO and Relish, to regulate autophagy at transcriptional level indirectly. 20E promotes the transcription of FOXO by binding to the promotor region and simultaneously induces the dephosphorylation of FOXO, which leads to cytoplasmic-nucleo translocation and upregulation of autophagy (Hossain et al, 2013; Cai et al, 2016)
20E affects the expression and PTM status of the transcription factors to promote their positive functions in autophagy occurrence, accompanying with its direct induction of Atg and V-ATPases gene expression in insects

Summary

INTRODUCTION

Macroautophagy, hereafter referred to as autophagy, is a self-eating process to recycle intracellular components and extensively exists in organisms under physiological and pathophysiological conditions (Klionsky et al, 2021). The transcriptional and posttranslational regulators of autophagy are usually linked, e.g., 20E signaling induces the expression of Atg genes and inhibits acetylation of Atg proteins simultaneously; 20E interacts with nutrient signaling to initialize autophagosome formation (Tian et al, 2013; Wu et al, 2021a). E93 upregulates the expression of almost all Atg genes in both Bombyx and Drosophila to promote autophagy, while JH represses the transcription of Bombyx BmE93, suggesting a negative role of JH in autophagy induction through interaction with 20E signals (Liu et al, 2014, 2015). 20E can induce a starvation-like conditions and reduces the activity of Insulin-Akt/PI3K-MTORC1 pathway to initiate autophagy in insects (Tian et al, 2013; Liu et al, 2015). TFEB activity is modulated by several different signaling pathways and plays a critical role in autophagy

Other Transcription Factors

MicroRNA and lncRNA

CONCLUSION