Porcine reproductive and respiratory syndrome virus envelope (E) protein interacts with mitochondrial proteins and induces apoptosis.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses for the swine industry worldwide. The PRRSV E protein, encoded by ORF 2b, is one of the non-glycosylated minor structural proteins. In this study, we present evidence for the interaction of the E protein with mitochondrial proteins ATP5A (part of ATP synthase complex), prohibitin, and ADP/ATP translocase. We additionally demonstrate partial mitochondrial localization of the E protein in transfected cells. To functionally investigate these interactions, we infected MARC-145 cells with PRRSV or alphavirus replicon particles (VRPs) expressing PRRSV E protein. In infected cells, production of ATP was significantly reduced. The E protein also induced apoptosis by activating caspase-3, which results in PARP cleavage. Taken together, these data suggest that the PRRSV E protein interacts with mitochondrial proteins and induces apoptosis by inhibiting ATP production.