Fig. 1. Functional and cryo-EM studies of C. albicans Cdr1.

a A schematic diagram of efflux pumps in C. albicans. Cdr1, Cdr2 and Mdr1 can expel azole antifungal drugs. Milbemycin inhibits Cdr1 and Cdr2 efflux activity. The green arrows indicate the direction of azole drug efflux. b Fluconazole-sensitivity assay by measuring OD_600nm under different fluconazole concentrations. The IC₅₀ value for the empty vector is 0.31 µg/mL (left figure), while Cdr1 overexpression raises the IC₅₀ value to 56.6 µg/mL (right figure). Data are presented as mean values ± SD; n = 3 independent experiments. c Milbemycin oxime-sensitivity assay measuring OD_600nm under different milbemycin oxime concentrations, with fluconazole concentrations of 0 µg/mL, 1 µg/mL, and 10 µg/mL. The IC₅₀ values for 1 µg/mL and 10 µg/mL fluconazole are 0.034 µg/mL and 0.009 µg/mL, respectively. Data are presented as mean values ± SD; n = 3 independent experiments. d Overall structures of Cdr1^Apo, Cdr1^Flu and Cdr1^Mil. TMD1 and NBD1 are depicted in sky-blue, while TMD2 and NBD2 are in orange. PIP2, fluconazole, and milbemycin oxime are colored by yellow, red, and green, respectively. The green shading represents plasma membrane region.