期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1982
卷号:79
期号:2
页码:350-354
DOI:10.1073/pnas.79.2.350
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:The endocytosis leading to degradation of 125I-labeled asialo-orosomucoid specifically bound to the surface of freshly isolated hepatocytes was monitored as a function of time at 37 degrees C. Experimental values were determined for the rates of internalization, dissociation of the receptor-ligand complex, and degradation of the labeled ligand. Compartmental analysis and computer modeling revealed that the data were compatible with dissociation of ligand from receptor preceding ligand degradation. The rate coefficient for internalization was calculated to be an order of magnitude greater than that for receptor--ligand dissociation. Ligand internalization did not result in concomitant depletion in the total number of cell surface receptors. Our data are taken to indicate that ligand remains associated with the receptor after internalization, that the complex is dissociated prior to degradation, and that new, unoccupied receptors are promptly returned to the cell surface from an internal pool.