Cellular Retinoic Acid Binding Protein 1 (CRABP1)

CRABP1 is a number of specific carrier proteins for members of the vitamin A family have been discovered. Cellular retinoic acid-binding protein is assumed to play an important role in retinoic acid-mediated differentiation and proliferation processes. CRABP1 is structurally similar to the cellular retinol-binding proteins, but binds only retinoic acid. CRABP1 is constitutively expressed and is believed to have different functions in the cell than the related CRABP2. Six such proteins have been well characterized: serum retinol-binding protein; cellular retinol-binding protein (CRBP); cellular retinoic acid-binding protein; cellular retinol-binding protein, unique to visual tissue; interphotoreceptor retinol-binding protein, also unique to visual tissue; and cellular retinol-binding protein, type II (CRBP2), present in small intestine.