Disease relevance of Crabp1

• Fifty-two percent of the primary carcinomas and 43% of the dysplastic breast lesions (stage MII) contained detectable amounts of crabp, whereas no cRABP was found in normal tissue [1].
• Induced adenocarcinomas were found to contain low levels of cellular retinoic acid-binding protein (10 pmol/g), similar to the levels found in adjacent mucosa of the same animal and also in colorectal mucosa from normal rats or rats chronically treated with DMH [2].
• To determine if retinol acts at the beta-cell level, we assayed beta-cells of the rat insulinoma (RINm5F) line for cytosolic retinol- and retinoic acid-binding proteins (CRBP and CRABP) by radioimmunoassay (RIA) and [3H]retinol and [3H]retinoic acid binding to cytosol extracts [3].
• CRBP I and CRABP I gene expression have been examined in the oviduct, ovary, uterus, and particularly in the cervix, which normally undergoes a cyclical squamous metaplasia during the estrus cycle [4].
• Fibroblasts in other regions of the oral cavity, such as the dermis of the skin of the cheek or the lamina propria of the buccal mucosa or of the diastema region, exhibited little or no staining for CRABP [5].

High impact information on Crabp1

• The cRABP of human origin (normal uterus and neoplastic mammary tissue) differed in its mobility in agarose electrophoresis from that of rat testis cRABP [1].
• Sucrose gradient centrifugation and electrophoresis on agarose were used for analysis of the presence of cRABP [1].
• The deficiencies in cAMP-dependent protein kinase may increase the expression of CRABP and the RARs; and, thus, cAMP may indirectly regulate the ability of RA to control neurite formation and neural differentiation [6].
• In contrast, the levels of retinoic acid receptors (RAR alpha and RAR beta), and retinoic acid binding protein (CRABP) mRNA were strikingly higher in both A126-1B2 cells and 123.7 cells than in the parental PC12 cells [6].
• Purified cellular retinoic acid binding protein (CRABI) complexed with retinoic acid did not diminish the amount of retinol bound to nuclei [7].

Chemical compound and disease context of Crabp1

• During the hepatocarcinogenesis, cellular retinoid-binding protein, F-type or CRBP(F) and cellular retinoic acid-binding protein or CRABP newly appeared in the tumor tissue, particularly in hyperplastic nodules which are the precancerous state of hepatoma [8].

Biological context of Crabp1

• The NH2-terminal amino acid sequence of cellular retinoic-acid binding protein from rat testis [9].
• In the ovary, CRABP was not detected, while CRBP levels remained relatively constant throughout the cycle and CRABP II peaked slightly during metestrus [10].
• The induction of pseudopregnancy by the injection of eCG in rats results in the appearance of cellular retinoic acid-binding protein type II (CRABP[II]) in the granulosa cells of the ovary and the lining epithelium of the uterus within 48 h [11].
• Northern and Western blot analysis of the uteri revealed a peak of CRBP during diestrus and a peak of CRABP during proestrus, whereas CRABP II peaked sharply during estrus [10].
• While the expression of CRBP I and CRABP I in the keratinizing exocervix changed during the estrus cycle, it remained constant in the incompletely keratinized endocervix [4].

Anatomical context of Crabp1

• The appearance of CRABP in the stroma of the uterus also correlated with PMSG injection as well as estrogen treatment [12].
• The presence of a novel cellular retinoic acid-binding protein in chick embryos: purification and partial characterization [13].
• Immunoreactivity with CRABP II and CRABP I antibodies was not observed in the nasal respiratory epithelium [14].
• CRABP I was localized to the basement membrane region of the epithelium with the strongest expression in the basal layer of epithelial cells [4].
• Ketoconazole inhibited the metabolism by testis microsomes of free and CRABP-bound retinoic acid with IC50 values of 2 and 0.7 microM, respectively, denoting catalysis by cytochrome P-450 [15].

Associations of Crabp1 with chemical compounds

• Two cellular retinoic acid binding proteins, CRABP I and II, which behaved differently on a DEAE-cellulose column, were purified from 14-day chick embryos [13].
• Cellular retinol-binding protein and cellular retinoic-acid-binding protein, canditates for mediating the action of vitamin A, were found to be present in tissues of the fetal rat [16].
• Rat colorectal mucosa was examined during the course of carcinogenesis, induced by chronic administration of 1,2-dimethylhydrazine (DMH), for the presence and amount of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein [2].
• Only in one tissue, the skin, were differences observed (lower CRABP in retinoid-deficient and in female rats) [17].
• Cellular retinoic acid-binding protein (CRABP) was detected in the nuclear fraction of N-methyl-N-nitrosourea-induced mammary cancers after the incubation of cytosol containing [3H]retinoic acid (RA)-bound CRABP with isolated nuclei [18].

Physical interactions of Crabp1

• We employed a monoclonal antibody to cellular retinoic acid-binding protein (CRABP) to assess the presence and localization of this retinoid-binding protein in the lacrimal gland of the rat [19].
• Retinyl methyl ether (RME) which prevents cancers of the rat mammary gland, binds to cellular retinol-binding protein and serum retinol-binding protein but not to cellular retinoic acid-binding protein or to the nuclear retinoid receptors, RARs/RXRs [20].
• Purified nuclei from rat testes interstitial cells were incubated with an equimolar complex of [3H]retinoic acid and purified cellular retinoic acid-binding protein (cRABP) and with ATP [21].

Other interactions of Crabp1

• Although estrogen induced the appearance of both binding proteins, CRABP mRNA levels peaked between 4-24 h postestrogen treatment, whereas CRABP II mRNA levels continued to rise 48 h postestrogen treatment [12].
• Double immunolabeling experiments, conducted with antibodies showing specificity for each antigen, indicate that CRABP II and CRABP I are found in different cell types within the olfactory neuroepithelium [14].
• Among cellular retinol-binding protein I (CRBP-I) and CRBP-II and cellular retinoic acid-binding protein I and II, only the CRBP-I gene was expressed [22].
• Cellular retinoic acid-binding protein has been purified to homogeneity from rat testes [23].
• It belongs to a family of fatty acid binding proteins and shows a 72% amino acid sequence similarity to aP2/422, the adipocyte lipid binding protein, a 58% sequence similarity to rat heart fatty acid binding protein, and a 40% sequence similarity to cellular retinoic acid binding protein [24].

Analytical, diagnostic and therapeutic context of Crabp1

• Amino-terminal sequence analysis showed that CRABP-II has a distinct sequence, while the CRABP-I sequence is exactly identical to that of the rat testis CRABP [25].
• The assay makes use of anion-exchange high-pressure liquid chromatography which effectively separates CRABP-II from CRABP-I, thus permitting the simultaneous quantitation of these two proteins [26].
• In contrast, two other vitamin A-binding proteins, cellular retinoic acid-binding protein, and serum retinol-binding protein, showed no cross-reaction in the radioimmunoassay [27].
• By use of an enzyme-linked immunosorbent assay CRABP was quantitatively estimated in several tissues and the highest levels were found in testis and eye [28].
• In contrast, cellular retinoic acid-binding protein was detected only the first day after hepatectomy, whereas no significant change was observed in the level of the cellular retinol-binding protein during the entire observation period [29].

References