STRA6 is a 667 amino acid, multi-pass cell membrane protein. Stra6 functions as a cell-surface receptor for the complex retinol-retinol binding protein (RBP/RBP4). Ultimately increasing cellular retinol uptake from the retinol-RBP complex, Stra6 removes retinol from RBP/RPB4 and transports it across the plasma membrane, where it is metabolized. Stra6 is broadly expressed, with 4 named isoforms that exist as a result of alternative splicing events. Mutations in the gene encoding Stra6 cause Matthew-Wood Syndrome, also known as Spear Syndrome. This syndrome is characterized by anophtalmia, mild facial dysmorphism and malformations of the heart, lung and diaphragm. The Stra6 gene maps to chromosome 15q24.1.