RAB27A and infection: Forty-eight hours post infection, cells were harvested and cytosolic fractions of the cells were isolated and used to perform in vitro prenylation assays in which the cytosolic cellular fraction served as the REP-1 protein source, RabGGTase, [3H]-GGPP as the prenyl group donor, and recombinant RAB27 as the substrate, as described previously [30], [38], [39].