Retinol-binding protein

From Proteopedia

1 Function
2 Relevance
3 Structural highlights
4 3D structures of retinol-binding protein

Function

Retinol-binding protein (RBP) are carrier proteins which bind retinol (vitamin A alcohol). Human RBP4 is the carrier of retinol in the blood. It delivers retinol from the liver to the peripheral tissues. RBP also functions in regulation, metabolism and activities of retinoids. Retinol is being protected from oxidation and becomes soluble when bound to RBP. RBP is classified according to its site of activity. Plasma RBP (PRBP) carries retinol in blood^[1] while cellular RBP (CRBP) carries retinol in the cell^[2].

Interphotoreceptor retinoid-binding protein (iRBP) is involved in the regeneration of rhodopsin in the visual cycle^[3].

Relevance

RBP is used to assess vitamin A deficiency as it binds 1:1 to retinol^[4]. RBP IV is used as biomarker for renal dysfunction and cardiovascular disease in type II diabetes^[5].

Structural highlights

Retinol binds to cellular RBP II inside its internal cavity^[6]. Active site. Water molecules are shown as red spheres.

3D structures of retinol-binding protein

Retinol-binding protein 3D structures

Human cellular retinol-binding protein II complex with retinol, sulfate and tartarate, 2rct

Drag the structure with the mouse to rotate

References

↑ Goodman DS. Plasma retinol-binding protein. Ann N Y Acad Sci. 1980;348:378-90. PMID:6994566
↑ Ong DE. Cellular retinoid-binding proteins. Arch Dermatol. 1987 Dec;123(12):1693-1695a. PMID:2825608
↑ Pepperberg DR, Okajima TL, Wiggert B, Ripps H, Crouch RK, Chader GJ. Interphotoreceptor retinoid-binding protein (IRBP). Molecular biology and physiological role in the visual cycle of rhodopsin. Mol Neurobiol. 1993 Spring;7(1):61-85. PMID:8318167 doi:10.1007/BF02780609
↑ Filteau SM, Willumsen JF, Sullivan K, Simmank K, Gamble M. Use of the retinol-binding protein: transthyretin ratio for assessment of vitamin A status during the acute-phase response. Br J Nutr. 2000 May;83(5):513-20. PMID:10953676
↑ Cabre A, Lazaro I, Girona J, Manzanares J, Marimon F, Plana N, Heras M, Masana L. Retinol-binding protein 4 as a plasma biomarker of renal dysfunction and cardiovascular disease in type 2 diabetes. J Intern Med. 2007 Oct;262(4):496-503. PMID:17875187 doi:http://dx.doi.org/10.1111/j.1365-2796.2007.01849.x
↑ Tarter M, Capaldi S, Carrizo ME, Ambrosi E, Perduca M, Monaco HL. Crystal structure of human cellular retinol-binding protein II to 1.2 A resolution. Proteins. 2008 Mar;70(4):1626-30. PMID:18076076 doi:http://dx.doi.org/10.1002/prot.21848