Facteurs de Croissance et Cytokines

CD42b, also known as GP1Ba (GP1B alpha, Glycoprotein 1Ba) is a single pass transmembrane glycoprotein that functions as the key ligand binding subunit of the GP1B platelet surface receptor. The association of CD42b/GP1Ba with GP1Bb (covalently) and platelet glycoproteins IX and V (non‐covalently) forms the von Willebrand factor receptor. The binding of von Willebrand factor (VWF) to its platelet receptor initiates the primary mechanism for the adhesion of platelets to a site of vascular injury and subsequent platelet activation. Additionally, the cytoplasmic (C‐terminal) domain of CD42b/GP1Ba can bind and activate signal transduction molecules, including 14‐3‐3ζ and β‐filamin. Mutations in von Willebrand factor and to a lesser extent, CD42b/GP1Ba, that affect the binding of VWF to the GP1B receptor are the primary cause of the hereditary bleeding disorder known as Type 2 von Willebrand disease (VWD). Mutations in the CD42b/GP1Ba gene have also been linked to a related bleeding disorder, Bernard‐Soulier disease. Recombinant Human sCD42b/GP1Ba is a 54.6 kDa protein containing 496 amino acid residues that correspond to the extracellular portion of CD42b/GP1Ba, plus a C‐terminal His‐Tag. Due to glycosylation, it migrates at approximately 100‐115 kDa by SDS‐PAGE analysis under reducing and non‐reducing conditions.