Responsible for the manifestation of peripheral-type benzodiazepine recognition sites and is most likely to comprise binding domains for benzodiazepines and isoquinoline carboxamides. May play a role in the transport of porphyrins and heme. Plays a role in the transport of cholesterol across mitochondrial membranes in steroidogenic cells. Belongs to the TspO/BZRP family. Interacts with BZRAP1. May interact with STAR. Interacts with MOST-1. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.