Retinol Binding Protein 7, Cellular (RBP7)

Due to its chemical instability and low solubility in aqueous solution, vitamin A requires cellular retinol-binding proteins (CRBPs), such as RBP7, for stability, internalization, intercellular transfer, homeostasis, and metabolism.CRBPIV shares 57%, 58%, and 49% amino acid identity with CRBPI (RBP1), CRBPII (RBP2), and CRBPIII (RBP5), respectively. RNA dot-blot analysis detected CRBPIV in nearly all tissues and cell lines examined, with highest abundance in adult kidney, followed by heart, transverse colon, fetal heart, fetal spleen, lymph node, appendix, and ascending colon.CRBPIV showed a lower binding affinity for retinol than those shown by other CRBPs, and the binding stoichiometry suggested that about 0.5 retinol-binding sites were utilized per CRBPIV molecule.