Bsg
Developmental stage
In uterus during peri-implantation period strongly expressed in the luminal epithelium on day 1 of pregnancy and gradually decreased to a basal concentration from day 3 to day 5 of pregnancy. Strongly expressed in the implanting blastocyst and primary decidua on day 6 of pregnancy.
Function
Isoform 1
Essential for normal retinal maturation and development (By similarity). Acts as a retinal cell surface receptor for NXNL1 and plays an important role in NXNL1-mediated survival of retinal cone photoreceptors (By similarity). In association with glucose transporter SLC16A1/GLUT1 and NXNL1, promotes retinal cone survival by enhancing aerobic glycolysis and accelerating the entry of glucose into photoreceptors (By similarity).
Isoform 2
Signaling receptor for cyclophilins, essential for PPIA/CYPA and PPIB/CYPB-dependent signaling related to chemotaxis and adhesion of immune cells (By similarity). Plays an important role in targeting the monocarboxylate transporters SLC16A1/GLUT1 and SLC16A3 to the plasma membrane (PubMed:10921872). Acts as a coreceptor for vascular endothelial growth factor receptor 2 (KDR/VEGFR2) in endothelial cells enhancing its VEGFA-mediated activation and downstream signaling (By similarity). Promotes angiogenesis through EPAS1/HIF2A-mediated up-regulation of VEGFA and KDR/VEGFR2 in endothelial cells (By similarity). Plays an important role in spermatogenesis; mediates interactions between germ cells and Sertoli cell and is essential for the development/differentiation of germ cells to round spermatids (By similarity).
Tissue Specificity
Isoform 2
Expressed in the skeletal muscle, liver, small intestine, kidney, testis, brain, heart and spleen (PubMed:8425897). Also present in various immature cells and endothelia (PubMed:2009910).
Cellular localization
- Isoform 1
- Cell membrane
- Single-pass type I membrane protein
- Photoreceptor inner segment
- Cell projection
- Cilium
- Photoreceptor outer segment
- Isoform 2
- Cell membrane
- Single-pass type I membrane protein
- Endoplasmic reticulum membrane
- Single-pass type I membrane protein
- Basolateral cell membrane
- Single-pass type I membrane protein
Alternative names
CD147, Basigin, Glycoprotein CE9, OX-47 antigen, Bsg