Decrease in membrane-associated actin of fibroblasts after transformation by Rous sarcoma virus

Abstract

The actin content of membranes prepared from cultured chick embryo fibroblasts has been measured on polyacrylamide gels. The actin was identified by tryptic peptide mapping. After transformation of the cells by Rous sarcoma virus, the amount of actin associated with the membranes is decreased by 30-50%. This result is not due to infection per se, since infection by a temperature-sensitive strain of the virus decreases membrane-associated actin only at the permissive temperature. A shift from the nonpermissive (41 degrees) to the permissive (36 degrees) temperature results in an increase in the percentage of total cellular protein synthesis devoted to actin production, so that the decrease in membrane-associated actin appears to be a selective displacement from the membrane rather than a general decrease in total cellular actin.