Cellular retinoic acid-binding protein 2 is a cytoplasmic binding protein that in humans is encoded by the CRABP2 gene.[5][6][7]

CRABP2
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesCRABP2, CRABP-II, RBP6, cellular retinoic acid binding protein 2
External IDsOMIM: 180231; MGI: 88491; HomoloGene: 1415; GeneCards: CRABP2; OMA:CRABP2 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001878
NM_001199723

NM_007759

RefSeq (protein)

NP_001186652
NP_001869

NP_031785

Location (UCSC)Chr 1: 156.7 – 156.71 MbChr 3: 87.86 – 87.86 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

CRABP2 is structurally similar to CRABP1, but CRABP2 has a lower affinity for retinoic acid (RA).[5] CRABP2 is associated with cells that produce large amounts of retinoic acid and may play a role in mediating the effects of retinoic acid in the cell.[5][8]

Function

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A number of specific carrier proteins for members of the vitamin A family have been discovered. Retinoic acid is an active metabolite of vitamin A (retinol).[8] Cellular retinoic acid binding proteins (CRABP) are low molecular weight proteins whose precise function remains largely unknown.

The inducibility of the CRABP2 gene suggests that this isoform is important in retinoic acid-mediated regulation of human skin growth, differentiation and development. CRABP2 is involved in the metabolism and transportation of retinoic acid from the cytosol to the RARs (retinoic acid receptors) located in the nucleus.[5][7][8][9] CRABP2 is specifically co-expressed with RAR-β and cellular retinol binding protein 1 genes in certain tissues.[5] It has been postulated that the CRABP2 gene is transcriptionally regulated by a newly synthesized regulatory protein.[7]

Tissue distribution

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Tissue distribution of the CRABP2 gene has primarily been studied using mouse models. During embryonic development, CRABP2 is present in tissues throughout the body in a more diffuse pattern than CRABP1.[5] CRABP1 is more isolated to specific regions, though it does appear in higher concentrations.[5] CRABP1 and 2 often overlap in tissues.[5]

CRABP2 gene expression is abundant in the trunk and hindbrain (and to a lesser extent the forebrain), but are present in other areas of the body.[5] Structures such as the limbs, hindbrain and cranial neural crest cells have been shown to be excessively sensitive to high levels of retinoic acid.[5] Rhombomere segmentation in the hindbrain and the development of cranial ganglia V, VII, VIII, IX, and X also appear to be partially dependent on CRABP2 expression.[5] CRABP2 is abundant in the dorsal part of the limb during development.[5]

CRABP2 genes are also expressed in structures that are less sensitive to retinoid levels throughout the body during embryonic development.[5] These structures include the pharyngeal pouches, foregut, midgut, mandibular and frontal mesenchyme, developing muscle, interdigital mesenchyme, the urogenital system, optic vessels, and inner ear sensory epithelium.[5]

Defects

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Vitamin A deficiency in mice has been shown to cause problems with spermatogenesis, irregular estrous cycles, changes in the uterine epithelium and reproductive failure ending with fetal death and reabsorption.[8]

Tissues with CRABP2 can be sensitive to high levels of retinoic acid which may cause defects in the development of those tissues.[5]

CRABP2 gene knockout studies should be performed to determine any specific defects caused by loss of this gene.

Interactions

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CRABP2 has been shown to interact with Cyclin D3.[10]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000143320Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000004885Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ a b c d e f g h i j k l m n o Ruberte E, Friederich V, Morriss-Kay G, Chambon P (Aug 1992). "Differential distribution patterns of CRABP I and CRABP II transcripts during mouse embryogenesis". Development. 115 (4): 973–987. doi:10.1242/dev.115.4.973. PMID 1333403. Archived from the original on 2016-03-04. Retrieved 2015-04-15.
  6. ^ Aström A, Tavakkol A, Pettersson U, Cromie M, Elder JT, Voorhees JJ (Sep 1991). "Molecular cloning of two human cellular retinoic acid-binding proteins (CRABP). Retinoic acid-induced expression of CRABP-II but not CRABP-I in adult human skin in vivo and in skin fibroblasts in vitro". The Journal of Biological Chemistry. 266 (26): 17662–6. doi:10.1016/S0021-9258(19)47422-X. PMID 1654334.
  7. ^ a b c "Entrez Gene: CRABP2 cellular retinoic acid binding protein 2".
  8. ^ a b c d Zheng WL, Ong DE (Apr 1998). "Spatial and temporal patterns of expression of cellular retinol-binding protein and cellular retinoic acid-binding proteins in rat uterus during early pregnancy". Biology of Reproduction. 58 (4): 963–970. doi:10.1095/biolreprod58.4.963. PMID 9546726.
  9. ^ Maden M, Ong DE, Summerbell D, Chytil F (April 1989). "The role of retinoid-binding proteins in the generation of pattern in the developing limb, the regenerating limb and the nervous system". Development. 107 Suppl: 109–119. doi:10.1242/dev.107.Supplement.109. PMID 2561479. Archived from the original on 2016-03-04. Retrieved 2015-04-15.
  10. ^ Despouy G, Bastie JN, Deshaies S, Balitrand N, Mazharian A, Rochette-Egly C, Chomienne C, Delva L (Feb 2003). "Cyclin D3 is a cofactor of retinoic acid receptors, modulating their activity in the presence of cellular retinoic acid-binding protein II". The Journal of Biological Chemistry. 278 (8): 6355–62. doi:10.1074/jbc.M210697200. PMID 12482873.
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Further reading

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