Retinoic acid-binding protein

A related family of proteins are represented by fatty acid-binding proteins1 ° and by the intracellular retinol- and retinoic acid-binding proteins (see also Box 22-A).p These are 10-stranded antiparallel P-barrels with two helices blocking an end (see Figure). 

Vitamin A absorbs UV light between 300 and 350 nm. After acute exposure to UVA or UVB a dose-dependent decrease of vitamin A was shown in mouse59 and humans.84 UV irradiation markedly reduced mRNA and protein of the nuclear retinoid receptors RARy and RXRa in humans and led to a near loss of retinoic acid induction of the RAR/RXR target genes and the cellular retinoic acid binding protein II thus effectively causing additionally a functional vitamin A deficiency.85... 

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. 

There are two cellular retinoic acid binding proteins ... 

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... 

Delva L, Bastie JN, Rochette-Egly C, Kraiba R, Balitrand N, Despouy G, Chambon P, and Chomienne C (1999) Physical and functional interactions between cellular retinoic acid binding protein II and the retinoic acid-dependent nuclear complex. Molecular and Cell Biology 19,7158-67. 

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. 

A Novel Method for Measuring the Binding Properties of the Site-Directed Mutants of the Proteins That Bind Hydrophobic Ligands Application to Cellular Retinoic Acid Binding Proteins... 

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. 

Cellular retinoic acid-binding protein II CRABPII Not determined Giguere et al. (1990)... 

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