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

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.