Two Retroviral Entry Pathways Distinguished by Lipid Raft Association of the Viral Receptor and Differences in Viral Infectivity (original) (raw)

The receptor “priming” model for entry of the retrovirus avian sarcoma and leukosis virus (ASLV) predicts that upon binding cell surface receptors, virions are endocytosed and trafficked to acidic endosomes where fusion occurs. To test this model directly, we have now followed subgroup A ASLV (ASLV-A) virions entering cells via either the transmembrane (TVA950) or glycophosphatidylinositol (GPI)-anchored (TVA800) forms of the cellular receptor. Our results suggest that viruses entering via these two forms of receptor are subjected to different intracellular fates, perhaps due to use of different endocytic trafficking pathways to access acidic fusion compartments. Kinetic analyses demonstrated that virus bound to TVA800 was taken up from the cell surface more slowly but then trafficked to the site of fusion more quickly than that entering via TVA950. Furthermore, transiently arresting virions within putative fusion compartments with NH 4 Cl led to a substantially greater decrease in ...