LAMP1 and infection: Hence, the clustering at infection sites of surface Lamp-1 in EPEC1 (expressing Tir only)-infected cells (exemplified in Fig. 6A ; Fig. S6) could be attributed to local Tir-triggered Ca2+ influx, which induces localized fusion of lysosomes with the infected plasma membrane, resulting in preferential insertion and localization of Lamp-1 at the infection sites.