| Abstract: | A Chinese hamster ovary (CHO) cell mutant resistant to the Na+/K+ ionophoric antibiotic, monensin, is partly defective in insulin-receptor activity. Growth of the monensin-resistant mutant required higher dose of insulin in defined medium than the parental CHO cell. Membrane proteins of CHO and a monensin-resistant clone, MonR-31, were compared for their capacity to be phosphorylated by endogenous phosphorylation enzyme in vitro in the absence or presence of insulin. Several membrane proteins of CHO were more highly phosphorylated as compared with MonR-31 in either the absence or presence of insulin. |
