Coat proteins, host factors and plant viral replication

It was once believed that the sole biological function of viral coat protein (CP) is to encapsidate the viral genome, protecting it from degradation. The past several decades have witnessed a shift in this paradigm towards recognizing CPs as multifunctional proteins involved in almost every stage of the viral infection cycle. Such functional diversity is achieved via specific CP interactions with viral and host components in the infected cell. Different CP functions are tightly regulated both temporally and spatially through a variety of mechanisms including post-translational modifications and competing interactions. In the present review, we summarize the nonstructural functions of plant viral CPs, placing special emphasis on their roles in viral genome replication and translation.