Structure of the STRA6 receptor for retinol uptake

• DOI: 10.1126/science.aad8266
• Publication Date: 2016-08-25T18:23:09Z
• Authors: Yunting Chen; Oliver B. Clarke; Jonathan Kim; Sean Stowe; Youn-Kyung Kim; Zahra Assur; Michael Cavalier; Raquel Godoy-Ruiz; Desiree C. von Alpen; Chiara Manzini; William S. Blaner; Joachim Frank; Loredana Quadro; David J. Weber; Lawrence Shapiro; Wayne A. Hendrickson; Filippo Mancia
• Keywords: Protein Conformation, alpha-Helical; 0301 basic medicine; Cryoelectron Microscopy; Membrane Proteins; Membrane Transport Proteins; Biological Transport; Zebrafish Proteins; Recombinant Proteins; Retinol-Binding Proteins; 03 medical and health sciences; HEK293 Cells; Calmodulin; Animals; Humans; Calcium; Protein Multimerization; Vitamin A; Protein Binding

A window into the cell for vitamin A

Vitamin A is an essential nutrient for mammals, and its metabolites affect diverse biological processes. It is carried in the bloodstream as retinol by retinol binding protein (RBP); a protein called STRA6 is implicated in facilitating retinol translocation across the cell membrane. Chen et al. determined the structure of zebrafish STRA6 to a resolution of 3.9 Å by electron microscopy. A lipophilic cleft is a likely binding site for RBP, and an opening in the cleft may allow retinol to diffuse into the membrane. Unexpectedly, the structure also includes bound calcium-modulated protein, but its function remains unclear.

Science , this issue p. 887