Cleavage of DAP5 by coxsackievirus B3 protease 2A causes its nuclear translocation and inhibition of IRES‐containing gene transcription (836.5)

Abstract

Coxsackievirus B3 (CVB3) is a primary causative agent of viral myocarditis which may progress to dilated cardiomyopathy (DCM), a leading cause of unexpected death in children and young adults. Upon infection, CVB3 hijacks host cellular translation machinery, generating an environment that favors viral replication. Death associated protein 5 (DAP5) is an internal ribosomal entry site (IRES) specific translation initiation factor, utilized by the cell in conditions of stress, differentiation, cell‐cycle and apoptosis. We previously showed that DAP5 is cleaved during CVB3 infection. In this study we aimed to identify the responsible protease and site of cleavage, as well as the functional impact. Our results found that DAP5 was cleaved by viral protease 2A but not by cellular proteases. We further identified the cleavage site at amino acid G434. Upon cleavage, the N‐terminal product could translocate to the nucleus and inhibited transcription of IRES‐containing pro‐survival genes such as Bcl‐2, GRP‐78 and VEGF. This is the first report to reveal the function and mechanism of DAP5 cleavage in regulating viral and host gene expression during CVB3 infection. Moreover, this study may identify key components necessary for facilitating viral pathogenesis and thus provide novel pharmaceutical targets for viral myocarditis.Grant Funding Source: Canadian Institutes of Health Research