title: Protein sequence of endothelial glycoprotein IIIa derived from a cDNA clone. Identity with platelet glycoprotein IIIa and similarity to "integrin".
abstract: Platelet membrane glycoprotein (GP) IIIa forms a Ca2+-dependent heterodimer complex with GP IIb. The GP IIb-IIIa complex constitutes the fibrinogen and fibronectin receptor on stimulated platelets. A biochemically and immunologically similar membrane glycoprotein complex is present on endothelial cells. A human umbilical vein endothelial cell cDNA library was screened using oligonucleotide probes designed from peptide sequences obtained from platelet GP IIIa. A cDNA clone was sequenced and found to encode a protein of 84.5 kDa. The translated endothelial cDNA contained five sequences that corresponded to peptide sequences in platelet GP IIIa, including the amino-terminal 19 residues. Thus, the endothelial and platelet forms of GP IIIa are apparently identical. Glycoprotein IIIa consists of a long amino-terminal extracellular domain with several potential N-linked glycosylation sites and four cysteine-rich tandem repeats, a 29-residue hydrophobic transmembrane segment, and a short carboxyl-terminal cytoplasmic domain. Glycoprotein IIIa has a 47% amino acid sequence homology to "integrin," a fibronectin receptor from chicken embryo fibroblasts. This homology suggests that GP IIIa is a member of a family of cell-surface adhesion receptors.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001792:Blood Platelets / Q000032:analysis*; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004727:Endothelium / Q000032:analysis*; D006031:Glycosylation; D006801:Humans; D016023:Integrins; D008565:Membrane Proteins; D010446:Peptide Fragments / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis
chemical_list: D016023:Integrins; D008565:Membrane Proteins; D010446:Peptide Fragments; D010980:Platelet Membrane Glycoproteins; D004247:DNA