MEMBRANE-PROTEIN CARBOXYL METHYLATION DOES NOT APPEAR TO BE INVOLVED IN THE RESPONSE OF ERYTHROCYTES TO CYTOSKELETAL STRESS

The effect of changes of human erythrocyte cell shape on the degree of covalent modification by carboxyl methylation of membrane cytoskeletal proteins was investigated. The cell probably does not utilize carboxyl methylation to respond to cytoskeletal perturbations caused by such agents as A23187 [calcimycin], 2,4-dinitrophenol and chlorpromazine, all of which cause large changes in cell shape. Protein carboxyl methylation also remained unchanged in the presence of cytochalasin B, which prevents such changes in cell shape. These results are not consistent with a cytoskeletal regulatory role for protein methylation reactions in the intact erythrocyte.