Subcellular localisation of ABC transporters. Cells transfected with ABCB4 or ABCC1 expression vectors were stained using antibodies to ABCB4 or ABCC1. (A) Wild type ABCB4, (B) mutant ABCB4. (C) ABCC1, (D) untransfected 293T cells. Nuclei were stained with DAPI. Strong immunoreactive staining was observed in cells expressing ABCB4, ABCB4mut and ABCC1.