Serum Retinol Binding Protein 4 Polyclonal Antibody

Description

Serum retinol binding protein 4 (sRBP4) binds one equivalent of vitamin A and is one of the major retinol carriers found in the blood of mammals. Human RBP4 is a monomeric 21 kDa β-sheet-rich protein that contains three disulfide bonds and belongs to the lipocalin protein family. sRBP4 is synthesized and sequestered in hepatocytes until retinol binding triggers its secretion. In plasma, sRBP4 typically forms a 1:1 complex with the 55 kDa tetrameric protein transthyretin (TTR) which prevents RBP from being removed from the plasma by glomerular filtration. Recent studies have shown that sRBP4 is an adipocyte-derived “signal” that may contribute to the pathogenesis of type 2 diabetes. Elevation of sRBP4 causes systemic insulin resistance whereas reduction of serum concentrations improves insulin action. The highest known concentrations of this protein exist in serum, liver, and skeletal muscle.