Temperature dependence of endocytosis mediated by the asialoglycoprotein receptor in isolated rat hepatocytes. Evidence for two potentially rate-limiting steps.

摘要: The rate of endocytosis cell surface-bound [3H]-asialo-orosomucoid was determined as a function temperature. Freshly isolated rat hepatocytes were allowed to bind [3H]asialo-orosomucoid at 4 degrees C, washed remove nonbound ligand, and internalization then assessed by the resistance cell-associated radioactivity release Ca2+ chelator EDTA. At 10 C or below, is negligible. Above proportional temperature but increase with increasing changes sharply about 20 C. From 10-20 apparent activation energy for endocytosis, calculated from an Arrhenius plot, 45.9 kcal/mol coefficient, Q10, 15.6. However, between 41 17.0 Q10 2.6. Although previously bound very dependent on temperature, final extent essentially temperature-independent 14 37 results suggest that there are least two steps in overall process mediated asialoglycoprotein receptor which can be potentially rate-limiting, one another approximately