Receptor-mediated endocytosis of tissue-type plasminogen activator (t-PA) by liver cells
| Autor: | Th.J.C. van Berkel, M. Otter, Johan Kuiper, Dingeman C. Rijken |
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| Rok vydání: | 1990 |
| Předmět: |
Protein Conformation
Liver cytology Liver receptor homolog-1 Molecular Sequence Data Receptors Cell Surface Hematology Receptor-mediated endocytosis In Vitro Techniques Biology Endocytosis Molecular biology Mannose-Binding Lectins Liver Tissue Plasminogen Activator Animals Humans Lectins C-Type Asialoglycoprotein receptor Amino Acid Sequence Receptors Immunologic Receptor Plasminogen activator Mannose Receptor Mannose receptor |
| Zdroj: | Thrombosis Research. 57:63-71 |
| ISSN: | 0049-3848 |
| Popis: | Tissue-type plasminogen activator (t-PA) has a short half-life in the circulation because the enzyme is rapidly cleared by the liver. This short review summarizes recent literature concerning mechanisms of uptake and degradation of t-PA in the liver. In vivo studies in rats show that degradation takes place via a lysosomal pathway. Saturation of the uptake system at high t-PA concentrations suggests a receptor-mediated mechanism. Competition experiments with various glycoproteins indicate that the asialoglycoprotein receptor is not involved, but they point to a role for the mannose receptor, which recognizes t-PA via its high mannose-type oligosaccharide on the first kringle domain. Both in vivo and in vitro studies with isolated liver cells demonstrate that parenchymal cells, as well as liver endothelial cells, are involved in the clearance of t-PA. Parenchymal cells, as the hepatoma cell line Hep G2, endocytose t-PA via a still unknown, possibly t-PA specific receptor, while liver endothelial cells catabolize t-PA via the mannose receptor. |
| Databáze: | OpenAIRE |
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