Proteolytic cleavage of host proteins by the Group IV viral proteases of Venezuelan equine encephalitis virus and zika virus

Publication date: Available online 10 February 2019Source: Antiviral ResearchAuthor(s): Elaine M. Morazzani, Jaimee R. Compton, Dagmar H. Leary, Angela V. Berry, Xin Hu, Juan Marugan, Pamela J. Glass, Patricia M. LeglerAbstractThe alphaviral nonstructural protein 2 (nsP2) cysteine proteases (EC 3.4.22.-) are essential for the proteolytic processing of the nonstructural (ns) polyprotein and are validated drug targets. A common secondary role of these proteases is to antagonize the effects of interferon (IFN). After delineating the cleavage site motif of the Venezuelan equine encephalitis virus (VEEV) nsP2 cysteine protease, we searched the human genome to identify host protein substrates. Here we identify a new host substrate of the VEEV nsP2 protease, human TRIM14, a component of the mitochondrial antiviral-signaling protein (MAVS) signalosome. Short stretches of homologous host-pathogen protein sequences (SSHHPS) are present in the nonstructural polyprotein and TRIM14. A 25-residue cyan-yellow fluorescent protein TRIM14 substrate was cleaved in vitro by the VEEV nsP2 protease, and the cleavage site was confirmed by tandem mass spectrometry. A TRIM14 cleavage product was also found in VEEV-infected cell lysates. At least ten other Group IV (+)ssRNA viral proteases have been shown to cleave host proteins involved in generating the innate immune responses against viruses, suggesting that the integration of these short host protein sequences into the viral protease cleavage site...
Source: Antiviral Therapy - Category: Virology Source Type: research