CRABP acid-binding protein

Anhydroretinol binds to plasma and intracellular RBPs, but not to the cellular retinoic acid binding proteins (CRABPs) or retinoid receptors. In experimental animals, it protects against the development of chemically induced tumors while showing none of the toxic effects of other retinoids. 

Retinoic acid may either enter the target cell from the circulation or may be formed intraceUularly by oxidation of retinol. A number of tissues - but not muscle, kidneys, small intestines, liver, lungs, or spleen - have a cellular retinoic acid binding protein (CRABP) that is distinct from CRBP. Testis and... 

Momoi T, Hanaoka K, and Momoi M (1990) Spatial and temporal expression of cellular retinoic acid binding protein (CRABP) along the anteroposterior axis in the central nervous system of mouse embryos. Biochemical and Biophysical Research Communications 169, 991-6. 

Many hydrophobic molecules such as vitamin A, vitamin D and steroid hormones play vital roles in a variety of cellular processes. Because of the low solubility of these molecules in water, it has been difficult to measure the binding properties of the site-directed mutants of the proteins that interact with these hydrophobic ligands such as cellular retinoic acid binding proteins (CRABPs) (Zhang et al. 1992 Chen et al. 1995). This has greatly hampered the studies of the quantitative structure-function relationships of these important proteins. 

After entering the cell, retinol and retinoic acid (RA) are bound by separate cytoplasmic proteins. These cytosolic proteins are called cytoplasmic-retinol binding protein (CRBP) artd cytoplasmic retinoic acid-binding protein (CRABP). Two forms of CRBP exist, and tw o forms of CRABP exist. One form of CRiiP occurs mainly In the villi of the small intestines, while the other form occurs in the liver and other organs. One form of CRABP occurs in the skin, while the other form occurs in many tissues. 

Cortical bone, 3 Cows, dietary fiber and, 143-144 Cow s milk, ailar gy to, 136 Coxsackievirus, selenium and, 830-831 C>peptide (connecting poplide), 42,167-168 CRABP (cytoplasmic rcHriode acid-binding protein), 560... 

Cellular retinoic acid-binding protein CRABP Not determined Sundeiin et al. (1985)... 

Re.seaa-h since the mid-1980s has taken va.si strides in determining the molecular mechanism of action of vitamin A. It appears that the vitamin exerts its biological function with respect to development, diffcrcnlialion. and metabolism like a steroid hormone. The biologically active species is believed to be retinoic acid. Two intracellular retinoic acid-binding proteins have been isolated. CRABP(I) and CRABPfll). The.se appear to have functions similar to those of the CRBPs. 

Adapalene is a naphthoic acid derivative, thus differing markedly from the endogenous retinoids. This rc.sults in different ability to bind the many retinoic acid-binding proteins. It binds with RARs but not RXRs or CRABPs." ... 

Retinoic acids, particularly trans-RA, bind with high affinity to cellular retinoic acid binding proteins I and II (CRABPI and CRABPII). Like the CRBPs, CRABPs are widely ex-... 

Oxidation of retinol produces retinoic acid tretinoin). The reaction is irreversible. Retinoic acid enters the portal blood, is transported bound to albumin, and is not stored to any great extent. The concentration of retinoic acid in plasma is normally 3-4 ng/mL. A biologically active metabolite, 5,6-epoxyretinoic acid, has been isolated from the intestinal mucosa of vitamin A-deficient rats following administration of H-retinoic acid. Several tissues have specific cellular retinoic acid-binding proteins (CRABPs). 

Maden, M., Horton, C., Graham, A., Leonard, L., Pizzey, J., Siegenthaler, G., Lumsden, A., Eriksson, U. 1992. Domains of cellular retinoic acid-binding protein I (CRABP I) expression in the hindbrain and neural crest of the mouse embryo. Mech. Dev. 37, 13-23. 

Cellular retinoic acid binding proteins (CRABPs) 32... 

Abbreviations used in this review APL, acute promyelocytic leukaemia CEF, chick embryo fibroblasts CRABP, cellular retinoic acid-binding protein ODC, ornithine decarboxylase RA, retinoic acid RARE, retinoic acid responsive element RAR, retinoic acid receptor RXR, retinoid X receptor TEMPO, 2,2,6,6-tetramethylpiperidine Y-oxide TOC, tracheal organ culture TPA, 12-<2-tetradecanoylphorbol-13-acetate TTNN, 6-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-2-naphthanoic acid TTNPB, 4-((.Q-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)propenyl)benzoic acid. 

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