RBP4/Retinol-Binding Protein 4: Proteins and Enzymes

Retinol-binding protein 4 (RBP4) is a Lipocalin superfamily molecule that transports vitamin A (retinol) and retinaldehyde in the serum. Retinaldehyde is the critical chromophore in the rhodopsin photoreceptor, while both it and retinoic acid regulate a multitude of cellular differentiation and proliferation effects through the intracellular receptors RAR and RXR. RBP4 is secreted primarily by hepatocytes and adipocytes into the blood where the RBP4-retinol complex interacts with transthyretin ...