SLCO1B1 and autosomal erythropoietic protoporphyria: Using these models, along with pharmacological inhibitors of OATP1B1/1B3, and OATP1B1/1B3-overexpressing cell lines, we systematically explored the role of OATP1B1/1B3 in bilirubin and PPIX homeostasis, as well as its impact on liver injury in EPP.