CD105, Recombinant, Human, Fc Chimera (Endoglin, gp160, TGF beta1,3 Receptor, ENG, END, ORW, HHT1, O

Endoglin (CD105) is a 90kD type I transmembrane glycoprotein of the zona pellucida (ZP) family of proteins (1-3). Endoglin and betaglycan/TbRIII are type III receptors for TGF beta superfamily ligands, sharing 71% aa identity with within the transmembrane (TM) and cytoplasmic domains. Endoglin is highly expressed on proliferating vascular endothelial cells, chondrocytes, and syncytiotrophoblasts of term placenta, with lower amounts on hematopoietic, mesenchymal and neural crest stem cells, activated monocytes, and lymphoid and myeloid leukemic cells (2-5). Human Endoglin cDNA encodes 658aa including a 25aa signal sequence, a 561aa extracellular domain (ECD) with an orphan domain and a two-part ZP domain, a TM domain and a 47aa cytoplasmic domain (1-3). An isoform with a 14aa cytoplasmic domain (S-endoglin) can oppose effects of long (L) Endoglin (6, 7). The human Endoglin ECD shares 65-72% aa identity with mouse, rat, bovine, porcine and canine Endoglin. Endoglin homodimers interact with TGF-b1 and TGF-b3 (but not TGF-b2), but only after binding TbRII (8). Similarly, they interact with activin-A and BMP-7 via activin type IIA or B receptors, and with BMP-2 via BMPR-1A/ALK-3 or BMPR-1B/ALK-6 (9). BMP-9, however, is reported to bind Endoglin directly (10). Endoglin modifies ligand-induced signaling in multiple ways. For example, expression of Endoglin can inhibit TGF-b1 signals but enhance BMP7 signals in the same myoblast cell line (11). In endothelial cells, Endoglin inhibits TbRI/ALK5, but enhances ALK1-mediated activation (12). Deletion of mouse Endoglin causes lethal vascular and cardiovascular defects, and human Endoglin haploinsufficiency can cause the vascular disorder, hereditary hemorrhagic telangiectasia type I (13, 14). These abnormalities confirm the essential function of Endoglin in differentiation of smooth muscle, angiogenesis, and neovascularization (2-4, 12-14). In preeclampsia of pregnancy, high levels of proteolytically generated soluble Endoglin and VEGF R1 (sFLT1), along with low placental growth factor (PlGF), are pathogenic due to antiangiogenic activity (15). Source: Recombinant corresponding to aa1-586 from human CD105 Fc Chimera at N-terminus and C-terminus expressed in CHO cells. Molecular Weight: ~87.3kD, Endotoxin: <1EU/1ug (LAL) , Biological Activity:, Measured by its binding ability in a functional ELISA. When recombinant human CD105 Fc Chimera is immobilized at 2ug/ml (100ul/well), the concentration of recombinant mouse TGF-b RI/ALK-5 Fc Chimera that produces 50% of the optimal binding response is found to be ~4-16ug/ml. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.