RBP4 Protein
Human Plasma.
Retinol Binding Protein 4, RBP-4, RBP4, Plasma retinol-binding protein, PRBP, RBP.
Sterile Filtered White lyophilized (freeze-dried) powder.
Greater than 95.0% as determined by SDS-PAGE.
Description
RBP4 Human produced in Pooled human plasma can be used as a calibrator in immunoassays. Immunoreactivity was checked using monoclonal antibodies specific to RBP4.
Product Specs
Retinol Binding Protein 4, RBP-4, RBP4, Plasma retinol-binding protein, PRBP, RBP.
Human Plasma.
Product Science Overview
Retinol Binding Protein-4 (RBP4) is a member of the lipocalin family and serves as the primary transport protein for retinol, commonly known as vitamin A, in the bloodstream . This protein plays a crucial role in the mobilization and distribution of vitamin A from the liver to various tissues in the body.
RBP4 is predominantly expressed in the liver, where the majority of the body’s vitamin A reserves are stored as retinyl esters . When the body requires vitamin A, these retinyl esters are hydrolyzed to retinol, which then binds to RBP4 within hepatocytes . The retinol-RBP4 complex subsequently associates with transthyretin (TTR), forming a larger complex that is released into the bloodstream . This association with TTR prevents renal filtration and ensures the efficient transport of retinol to target tissues .
Vitamin A is essential for numerous physiological processes, including vision, immune function, reproduction, embryonic development, and the regulation of cell proliferation and differentiation . The active metabolite of vitamin A, all-trans retinoic acid (atRA), acts as a high-affinity ligand for retinoic acid receptors (RARs), which are nuclear receptors that regulate gene expression . Additionally, 11-cis retinaldehyde, a derivative of vitamin A, serves as the light-sensitive chromophore in the visual cycle within the retina .
RBP4 delivers retinol to tissues by binding to specific membrane receptors. Two distinct RBP4 receptors have been identified, which mediate the uptake of retinol across cell membranes and, under certain conditions, facilitate bi-directional retinol transport . One of these receptors, known as “stimulated by retinoic acid 6” (STRA6), plays a critical role in maintaining retinoid homeostasis .
Mutations or defects in RBP4 can lead to various conditions and diseases due to dysregulated retinoid homeostasis . These conditions can affect embryonic development, vision, metabolism, and cardiovascular health . Beyond its role in retinol transport, RBP4 has been implicated in non-canonical functions, further highlighting its importance in human health .
