Stimulated by retinoic acid gene 6 protein (STRA6) (STRA6)

Stimulated by retinoic acid gene 6 protein (STRA6) is a specialized multi-pass transmembrane protein that serves as the primary cell-surface receptor for the retinol-binding protein (RBP4), the major carrier of vitamin A in the blood (UniProt Q9BX79). In the liver, STRA6 is predominantly expressed in hepatic stellate cells (HSCs), which are the principal storage sites for the body's vitamin A reserves (PubMed: 22665456). The protein facilitates the uptake of retinol from the extracellular RBP4-retinol complex and its transfer to intracellular retinol-binding proteins. Beyond its transport function, STRA6 acts as a signaling receptor that activates the JAK/STAT pathway upon RBP4 binding, influencing insulin signaling and lipid metabolism (PubMed: 19114986). Dysregulation of STRA6 is implicated in liver fibrosis, where activated stellate cells lose their vitamin A content, and in metabolic disorders such as type 2 diabetes and obesity (PubMed: 24657751). Furthermore, loss-of-function mutations in the STRA6 gene are the cause of Matthew-Wood syndrome, a severe developmental disorder characterized by anophthalmia and lung hypoplasia (NIH: OMIM). Therapeutic strategies targeting STRA6 or its ligand RBP4 are currently being investigated for their potential to treat metabolic and fibrotic diseases by modulating vitamin A homeostasis and associated signaling pathways (PubMed: 25301683).

Other names

Retinol-binding protein receptorRBP receptorStimulated by retinoic acid 6Hepatic stellate cell vitamin A uptake receptor

Mediates the uptake of retinol from the extracellular retinol-binding protein (RBP4) into the cytoplasm and triggers JAK2/STAT5 signaling upon RBP4 binding (PubMed: 19114986).