|CD42c||GPIbβ (platelet glycosylation)|
|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Lineage Restricted Molecule|
Type 1 glycoprotein
|24 / 24|
160 / 160
|CD42c is expressed and restricted on platelets and megakaryocytes. Red blood cells, granulocytes, T cells and thymocytes do not express CD42c. The CD42 complex is a major component of the platelet surface with 25,000 copies per platelet. CD42c is also expressed in non-hematopoietic tissues such as endothelium, brain and heart.|
|MOLECULAR FAMILY NAME: Belongs to the mucin family. |
CD42c is a β chain single-pass type-1 181 aa glycoprotein. It contains an 122 aa extracellular domain which contains 1 24 aa tandem leucine-rich sequence flanked by 22 aa consensus sequences, 1 potential N-glycosylation site and 1 phosphorylation site at Ser166, a 25 aa transmembrane domain which participates in signaling through phosphorylation of its intracellular domain and and a 34 aa cytoplasmic domain. CD42c belongs to the mucin family which is part of the leucine-rich repeat family. CD42c forms a disulfide-linked heterodimer with an a chain CD42b and a b chain CD42c. It forms a non-covalent linked complex with CD42a. Unlike CD42b, which is rich in O-linked oligosaccharides, CD42c has only N-linked chains of the lactosamine type.
A 411 aa protein arising from a longer, unspliced transcript in endothelial cells has been described, however, the authenticity of this product has been questioned.
There is 1 potential N-glycosylation site. Acylation, primarily palmitoylation, of GPIb has been found. There is a phosphorylation site at Ser166, which can be phosphorylated by cAMP dependent protein kinase.
|CD42c complex binds von Willebrand factor and thrombin.|
LIGANDS AND MOLECULES ASSOCIATED WITH CD42c
|CD42c combines with CD42b, CD42a and CD42d to form a complex which functions as a receptor for von Willebrand factor. The complex mediates adhesion of platelets to subendothelial matrics, which are exposed upon damage to the endothelium, at high shear rates. It also amplifies the platelet response to thrombin during platelet activation where thrombin is involved. Phosphorylation of the Ser-166 in CD42c may regulate cytoskeleton interactions in platelets.|
The CD42a-d complex serves as receptor for von Willebrand factor (vWf) and thrombin.
DISEASE RELEVANCE AND FUNCTION OF CD42c IN INTACT ANIMAL
Mutations of CD42c gives rise to Bernard-Soulier syndrome (BSS) which is a bleeding disorder with the presence of giant platelets and is characterized by the absence of the GPIb/IX/V CD42a-d complex. So far mutations have been found in the genes encoding CD42a, CD42b and CD42c in patients with BSS.
|MOLECULAR INTERACTIONS -|
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD42c
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD42c
Database accession numbers
Revised June 25, 2008