Encephalomyocarditis virus non-structural protein 2C degrades NDP52 autophagy protein to promote its own survival

Abstract

Encephalomyocarditis virus (EMCV) is an important zoonotic pathogen that causes encephalitis and myocarditis, primarily in pigs and in some mammals. Nuclear dot protein (NDP) 52 is an important autophagy adaptor protein that is known to target microbial pathogens, including viruses into autophagosomes to facilitate the selective autophagy process. Here, we wanted to investigate how an important zoonotic virus such as EMCV interacts with NDP52. We found that NDP52 negatively regulates the entry and replication phases of EMCV and interacts with EMCV VP1/VP2 proteins to mediate its autophagic degradation. EMCV counteracts this by exerting autophagy induction through its encoded 2C protein. The autophagy machinery then hijacks NDP52 and transports it to lysosomes for subsequent degradation via late endosomal molecules Rab7 and Rab9. Our study describes a novel mechanism by which EMCV escapes the hosts antiviral response to promote its survival by hijacking the autophagy pathway using the non-structural protein 2C of EMCV. ImportanceEMCV is an important zoonotic pathogen that can induce autophagy, but the regulatory role of autophagy receptors in EMCV infection has been rarely reported. Herein, we show that NDP52 is a novel host limiting factor for EMCV, which not only inhibits early EMCV endocytosis, but also restricts EMCV replication in vitro by controlling autophagic degradation of EMCV structural proteins VP1 and VP2. In order to counteract this, EMCV uses the N-terminal region of its non-structural protein 2C to interact with NDP52, and hijacks the autophagy machine to transport NDP52 to lysosomes for degradation, which weakens NDP52-mediated degradation of VP1 and VP2. Importantly, we reveal a novel mechanism by which EMCV evades the host antiviral response, contributing to a deeper understanding of the infectious mechanism of EMCV and providing new ideas for the design of antiviral drug targets.