FIG 8 .

Model of LASV entry into cells ± Lamp1. After initial attachment to α-DG at the cell surface, LASV particles are internalized into compartments within the endocytic pathway. The proposed pathway for Lamp1-negative (KO) cells (left) indicates LASV GPC-mediated fusion and entry from highly acidic endosomes. In Lamp1-positive (WT) cells, the receptor switch to Lamp1 elevates the pH threshold for GPC-mediated fusion, ensuring efficient entry from a less acidic endosome. We further propose that entry in Lamp1-positive cells is more efficient because the particles avoid inactivation by extremely low pH and/or proteases within less hospitable, Lamp1-negative endosomes.