Single-Particle Tracking of HIV-1 Virions Bearing an Extra-Viral Fluorescent pH Sensor Reveals Viral Entry occurs after Trafficking to an Acidic Cellular Compartment

The HIV-1 infectious cycle begins with viral glycoprotein mediated fusion with the host cell membrane and subsequent entry of the viral capsid to the host cytosol. It has been proposed that HIV-1 fusion and productive entry occur at the plasma membrane (PM) because functionality of the HIV-1 fusion glycoprotein (Env) is pH-independent. Further supporting this hypothesis are the observations that HIV-1 mediates fusion between adjacent cells and...