In Ixodes scapularis, the knockdown of the X-linked inhibitor of apoptosis protein (XIAP), which possesses a really interesting new gene (RING) zinc-finger motif that exhibits E3-ubiquitin ligase activity, increased the colonization by Anaplasma phagocytophilum, showing that E3 is important for the control of infection [56]. This evidence concerns the gene XIAP and infection.