The receptor for tissue plasminogen activator (t-PA) in complex with its inhibitor, PAI-1, on human hepatocytes.
The binding of t-PA-PAI-1 to human hepatocytes at 4 degrees C reached a maximum at 2 h. Scatchard analysis indicated 74,000 +/- 11,000 high-affinity binding sites for complex per human hepatocyte, with a Kd of 0.87 +/- 0.09 nM. Almost identical results were achieved with the human hepatoma cell line Hep G2. Binding of [125I]t-PA-PAI-1 complex was unaffected by high concentrations of unlabelled t-PA, PAI-1, u-PA or u-PA-PAI-1 complex; only t-PA-PAI-1 complex competed for binding. Hepatocyte-bound t-PA-PAI-1 was internalized and degraded at 37 degrees C. Thus, hepatocytes have a specific t-PA-PAI-1 receptor that participates in clearance of this complex.
Wing
L R
LR
Department of Molecular & Cell Biology, University of Aberdeen, Scotland, UK.
Bennett
B
B
Booth
N A
NA
D001667:Binding, Competitive; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008113:Liver Neoplasms / Q000378:metabolism; D015849:Plasminogen Inactivators / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013379:Substrate Specificity; D010959:Tissue Plasminogen Activator / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D015849:Plasminogen Inactivators; D011956:Receptors, Cell Surface; C067262:PLAT protein, human; D010959:Tissue Plasminogen Activator