# Identification, Expression of AaSQSTM1 in Aedes albopictus and Its Autophagic Function Analysis

## TL;DR

This study identifies and analyzes an autophagy-related protein in the Asian tiger mosquito, which could help understand its role in mosquito biology and disease transmission.

## Contribution

The study identifies and characterizes a novel autophagy receptor homolog, AaSQSTM1, in Aedes albopictus mosquitoes.

## Key findings

- AaSQSTM1 expression varies across developmental stages and tissues in Aedes albopictus.
- AaSQSTM1 can be used as a marker for autophagy activity when combined with Atg8 in C6/36 cells.
- Blood-feeding increases AaSQSTM1 and AaAtg8 expression in female mosquito ovaries.

## Abstract

Aedes albopictus (the Asian tiger mosquito) poses a serious threat to human health worldwide by transmitting dengue and other arboviral diseases. Autophagy is an evolutionarily conserved catabolic process in eukaryotic cells that regulates the metamorphosis, reproduction, and lifespan of insects. We identified a mammal autophagy receptor p62/SQSTM1 homolog in Ae. albopictus, named AaSQSTM1. Quantitative analysis showed distinct AaSQSTM1 expression levels across various developmental stages and female tissues. We also demonstrated that AaSQSTM1 could be used as a useful marker to estimate autophagy activity with the autophagy-related protein Atg8 in C6/36 cells. This study provides a basis for exploring the function of autophagy in Ae. albopictus mosquitoes.

Autophagy is a central pathway involved in maintaining cellular homeostasis during development, metabolism, and regeneration. The selective autophagy receptor p62/SQSTM1 is a multifunctional protein that plays a critical role in regulating autophagic activity by interacting with LC3/Atg8 proteins and ubiquitinated substrates. Aedes albopictus has rapidly spread worldwide and poses a serious threat to human health by transmitting dengue and other arboviral diseases. In the present study, we identified a putative p62/SQSTM1 homolog protein (AaSQSTM1) in Ae. albopictus, which contains conserved structural regions, including the Atg8 family interaction motif (AIM) and ubiquitin-associated (UBA) domain. The expression levels of AaSQSTM1 and AaAtg8 varied from the egg stage to the adult stage in Ae. albopictus. Quantitative analyses revealed that blood-feeding upregulated the expression levels of AaSQSTM1 and AaAtg8 in the ovaries of female adults. AaSQSTM1 was applied to monitor autophagic activity alone or with AaAtg8 by assaying endogenous protein levels and overexpressing fluorescent reporters in C6/36 cells. Our study revealed that AaSQSTM1 regulates the autophagic activity with AaAtg8, providing a basis for studying the autophagy process in mosquitoes.