Cleavage of SQSTM1/p62 by the Zika virus protease NS2B3 prevents autophagic degradation of viral NS3 and NS5 proteins.

ABSTRACT

Macroautophagy/autophagy plays a crucial role in inhibiting viral replication and regulating the host's immune response. The autophagy receptor SQSTM1/p62 (sequestosome 1) restricts viral replication by directing specific viral proteins to phagophores for degradation. In this study, we investigate the reciprocal relationship between Zika virus (ZIKV) and selective autophagy mediated by SQSTM1/p62. We show that NS2B3 protease encoded by ZIKV cleaves human SQSTM1/p62 at arginine 265 (R265). This cleavage also occurs with endogenous SQSTM1 in ZIKV-infected cells. Furthermore, overexpression of SQSTM1 inhibits ZIKV replication in A549 cells, while its absence increases viral titer. We have also shown that SQSTM1 impedes ZIKV replication by interacting with NS3 and NS5 and directing them to autophagic degradation, and that NS2B3-mediated cleavage could potentially alter this antiviral function of SQSTM1. Taken together, our study highlights the role of SQSTM1-mediated selective autophagy in the host's antiviral defense against ZIKV and uncovers potential viral evasion strategies that exploit the host's autophagic machinery to ensure successful infection.Abbreviation Cas9 CRISPR-associated protein 9; Co-IP co-immunoprecipitation; CRISPR clustered regularly interspaced short palindromic repeats; DENV dengue virus; GFP green fluorescent protein; IFA indirect immunofluorescence assay; KIR KEAP1-interacting region; KO knockout; LIR MAP1LC3/LC3-interacting region; mAb monoclonal antibody; NBR1 NBR1 autophagy cargo receptor; OPTN optineurin; pAb polyclonal antibody; PB1 Phox/BEM1 domain; R265A, a SQSTM1 construct with the arginine (R) residue at position 265 replaced with glutamic acid (A); SQSTM1 sequestosome 1; SQSTM1-C, C-terminal fragment of SQSTM1; SQSTM1-N, N-terminal fragment of SQSTM1; SVV Seneca Valley virus; TAX1BP1 Tax1 binding protein 1; TBD TRAF6-binding domain; TCID50 50% tissue culture infective dose; UBA ubiquitin-associated domain; Ub ubiquitin; WT wild type; ZIKV Zika virus; ZZ ZZ-type zinc finger domain.