The association of viral proteins with host cell dynein components during virus infection.

After fusion with the cellular plasma membrane or endosomal membranes, viral particles are generally too large to diffuse freely within the crowded cytoplasm environment. Thus, they will never reach the cell nucleus or the perinuclear areas where replication or reverse transcription usually takes place. It has been proposed that many unrelated viruses are transported along microtubules in a retrograde manner using the cellular dynein machinery or, at least, some dynein components. A putative employment of the dynein motor in a dynein-mediated transport has been suggested from experiments in which viral capsid proteins were used as bait in yeast two-hybrid screens using libraries composed of cellular proteins and dynein-associated chains were retrieved as virus-interacting proteins. In most cases DYNLL1, DYNLT1 or DYNLRB1 were identified as the dynein chains that interact with viral proteins. The importance of these dynein-virus interactions has been supported, in principle, by the observation that in some cases the dynein-interacting motifs of viral proteins altered by site-directed mutagenesis result in non-infective virions. Furthermore, overexpression of p50 dynamitin, which blocks the dynein-dynactin interaction, or incubation of infected cells with peptides that compete with viral polypeptides for dynein binding have been shown to alter the viral retrograde transport. Still, it remains to be proved that dynein light chains can bind simultaneously to incoming virions and to the dynein motor for retrograde transport to take place. In this review, we will analyse the association of viral proteins with dynein polypeptides and its implications for viral infection.