CRABP1: Proteins and Enzymes

Retinoic acid (RA), a metabolite of vitamin A, plays an important role in growth and differentiation by modulation of expression of certain genes. RA functions through its interaction with the nuclear protein, retinoic acid receptor (RAR) and the 9-cis RA with retinoid X receptor (RXR). The Cellular Retinoic Acid Binding Proteins (CRABP) bind RA with a high affinity and belong to the family of fatty acid binding proteins. Two forms of CRABP have been characterized, CRABP 1 and CRABP 2 which share ~75% sequence conservation. The main role of CRABP 1 may be to protect retinoids from non-specific dehydrogenases and direct them to specific enzymes. The precise role of CRABP 2 is still poorly understood but it seems to play a role in the interaction of ligands (RA, 9-cis RA) with nuclear receptors (RAR/RXR).