SPRR1B and infection: We found that the outside-in skin barrier was damaged after infection with Cdc42N17 (Figure S7A). As in the Cdc42 KO mice, a considerable increase in TEWL was found after Cdc42N17 infection (Figure S7B). Similar to the Cdc42 KO epidermis, the Cdc42- suppressed epidermis showed increased expression of SPRR1B, SPRR2D, and SPRR2G that expanded from the SC to all other layers except the SB (Figure S7C-D).