Clink, a nanovirus-encoded protein, binds both pRB and SKP1.

Clink, a 20-kDa protein of faba bean necrotic yellows virus, a single-stranded DNA plant virus, interacts with pRB family members and a SKP1 homologue from Medicago sativa. An LxCxE motif and an F-box of Clink mediate the interactions with the respective proteins. The capacity of Clink to bind pRB correlates with its ability to stimulate viral replication. Interaction of a single protein with the cell cycle regulator pRB and SKP1, a constituent of the ubiquitin-protein turnover pathway, appears to be a novel feature. Hence, Clink may represent a new class of viral cell cycle modulators.