Usutu virus NS4A induces autophagy and is targeted by the selective autophagy receptor p62/SQSTM1 for degradation

ABSTRACT: Usutu virus (USUV) is an emerging orthoflavivirus, which mainly affects birds but in rare cases can cause severe neuroinvasive disease in humans. Due to the limited size of the orthoflavivirus genome the virus relies on the host machinery for replication. In addition, it must subvert the host antiviral response for successful replication in the cell. Studying this complex network of virus-host protein interactions by proteomics approaches can provide us new insights in the replication cycle of viruses and can help us better understand the viral pathogenesis. We have previously shown that the USUV protein NS4A acts as an antagonist of the interferon response, and here we further map the host interaction partners of USUV NS4A using proximity labeling coupled to mass spectrometry. The resulting NS4A interactome revealed many host proteins involved in the autophagy pathway. We showed that both USUV infection and overexpression of USUV NS4A can induce the autophagy pathway. However, stimulation or inhibition of the autophagy pathway did not affect USUV replication in general. Therefore, we decided to look specifically at the role of the selective autophagy receptor sequestosome 1 (p62/SQSTM1), which was identified as an interaction partner of USUV NS4A. We found that p62 is involved in the degradation of USUV NS4A. Furthermore, the knockdown of p62 enhanced replication of USUV in A549 cells, which means p62 functions to restrict USUV replication. In conclusion, this study showed that USUV NS4A induced autophagy and was then targeted by p62 for degradation by the autophagic machinery, uncovering a new role of p62 in the antiviral defense against USUV.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Rayman Tjokrodirijo  

LAB HEAD: Peter A. van Veelen

PROVIDER: PXD057492 | Pride | 2025-05-07

REPOSITORIES: Pride