Figure 1:

PS receptors enhance viral entry. (a) A panel of PS receptors have been tested for their enhancing effect on viral entry. Among these, TIM proteins and CD300a are shown to directly promote viral entry. Gas6 and MFG-E8 bridge PS and the integral membrane proteins Axl and integrin, respectively, to enhance viral attachment. Stabilin, RAGE, and BAI1 are PS receptors that have not yet been shown to enhance the entry of any viruses. (b) PS receptors enhance viral entry through any four of the indicated viral entry pathways. PS receptors can augment the binding of a PS-containing virion on the plasma membrane thus enhancing viral fusion. PS receptors can also mediate the internalization of virions through micropinocytosis, clathrin-mediated endocytosis, and caveolin-mediated endocytosis, which allow viruses to be internalized for fusion in the endosome.