A model of viral PS receptor usage.

Abstract

<p>Human TIM proteins (TIMs) and other PS-binding receptors efficiently, but nonspecifically, promote internalization of various enveloped viruses. The TAM receptors Axl, Mer and Tyro (TAMs) similarly bind and internalize many viruses, albeit indirectly via the PS-binding bridging proteins Gas6 and/or Protein S (Prot S) in serum <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003232#ppat.1003232-Morizono1" target="_blank">[35]</a>. For most viruses PS-dependent internalization results in a moderate to strong increase of productive infection. Note that the degree of enhancement will depend on the cellular background in which experiments are performed. However, in the case of other viruses, PS receptor-mediated internalization may lead to a compartment that is not productive for infection. In addition, there is a third class of viruses, which is not efficiently bound and/or internalized by PS receptors. The indicated viruses were categorized based on hTIM1 usage and internalization results obtained with pseudoviruses and VLPs (black) or replication-competent viruses (blue). Note, however, that the consequences or efficiency of internalization can vary depending on the PS receptors and their expression levels.</p