FIGURE 1.

A schematic of viral entry pathways. (a) A nonspecifically adsorbed virus particle can desorb with rate k_d, or it can (b) recruit and specifically bind a receptor. The receptor can immediately initiate membrane fusion with rate k_f as shown in panel c, or, it can recruit additional receptor molecules, inducing wrapping of the virus particle. From partially wrapped states (d), the virus can at any stage undergo membrane fusion (e), or, it can completely wrap and internalize the virus particle (f and g).