Glycoprotein V, Recombinant, Human (CD42d, GPV, Platelet glycoprotein V, GP5)

GPV (platelet glycoprotein V; designated CD42d) is an 83kD type I transmembrane (TM) glycoprotein of the leucine-rich repeat (LRR) family. It is expressed exclusively within the platelet/megakaryocyte lineage, where it noncovalently interacts with other platelet TM LRR proteins, GPIba/b and GPIX, at a rati o of one GPV to two of each other subunit. The GPI-V-IX complex tethers platelets to von Willebrand factor on the surface of injured endothelial cells. Absence of the complex results in Bernard-Soulier syndrome, a rare bleeding disorder. The human GPV cDNA encodes a 560aa protein with a 16aa signal sequence, a 507aa extracellular domain (ECD) containing 15 LRR, a 21aa TM sequence, and a short (16aa) cytoplasmic tail that binds calmodulin in resting, but not activated platelets. The human GPV ECD shares 70%, 71% and 81% aa identity with mouse, rat and equine GPV, respectively. GPV can form soluble fragments of 80kD by ADAM10 or ADAM17 cleavage after P507, or 69kD by thrombin cleavage after R476. High circulating soluble GPV may be an indicator of platelet activation, but may also be caused by high doses of aspirin. The function of GPV is not entirely clear. Deletion of GPV in mice does not produce any obvious change to surface expression or function of GPIb and GPIX, but surface expressi on of GPV requires GPIb. Deletion studies also indicate that GPV may play a minor role in collagen adhesion, and may modify platelet aggregation in response to thrombin.||Recombinant protein corresponding to Gln17-Gly523 with a C-terminal 6-His tag from human Glycoprotein V expressed in NS0 cells.||Molecular Weight: |~75-85kD under reducing conditions||Biological Activity:|Measured by the ability of the immobilized protein to support the adhesion of thrombin-activated human platelets. When 5x10e6 cells/well are added to rhGPV coated plates (5ug/ml, 100ul/well),~50-70% will adhere after 1hr at 37°C.||Storage and Stability:|Lyophilized and reconstituted products are stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.