Figure 4.

Equivalent circuit of host cell membrane before and after virus infection. The membrane potential (V_m) of the host cell plasma membrane (m) at rest is generated by the parallel arrangement of active and passive transporters (black lines). The active transporter, the proton ATPase, has an inherent resistance R_p and creates a battery voltage E_p (ca. −400 mV). The parallel transporters (channels, carriers etc.) are summarized here with their resistance R_T and their equilibrium voltage E_T (< 0 mV). Because R_p ≪ R_T, V_m is very negative at rest. During infection the electrical properties of the viral particle, which contains the K⁺ channel with the resistance R_K, are connected (gray lines) via a low resistance fusion pore (R_F) with the membrane of the host. Because R_K ≪ R_p and R_T, V_m becomes dominated by E_K, i.e., depolarizes