FIGURE 8.

Schematic representation of the proposed RBP4 binding motif on RBPR2 for retinol uptake, storage, and distribution.Shown are the proposed RBP4 amino acid binding residues on STRA6 (YGG) and RBPR2 (SYL) that utilize a lock and key model mechanism to bind and stabilize the extracellular RBP4-retinol complex. The interaction interface between the membrane receptor and its’ ligand is stabilized by both hydrophilic and hydrophobic interactions for retinol internalization. The proposed binding residues for both RBP4-ROL receptors are color-coded based on the property of the amino acid residues.