NECTIN1 and infection: In P2 neurons, HSV-1 entry was not enhanced 1 h after infection, consistent with the finding that, as well as the loss-of-function P2-M3 TMEFF1, P2’s cells also expressed two neutral or hypomorphic mutant forms of TMEFF1: P2-M1, which after overexpression was present in normal amounts on the cell membrane and displayed normal levels of interaction with NECTIN-1, and P2-M2, which was less abundant on the cell membrane and also had lower levels of interaction with NECTIN-1 (Fig. 2d–f and Fig. 4i).