PROS1 and infection: The serum components involved in facilitating infection of several enveloped viruses, such as dengue virus, Ebola virus, HIV, and poxviruses, have been identified to be phosphatidylserine (PtdSer) binding serum proteins (Protein S, Gas6, and Mer), which act as bridging molecules for TAM receptors (Tyro3, Axl and Mer) expressed on macrophages during infection via clathrin-mediated endocytosis [80,81,82].