FIG. 10.

Mutation of Thr-58 increases c-Myc stability. (A) NIH 3T3 cells were transiently transfected with 2 μg of a plasmid encoding wild-type (WT) murine c-Myc or c-Myc with a Thr-58-to-Ala mutation (T58A). Forty-eight hours after transfection, the cells were subjected to pulse-chase analysis as described in the legend to Fig. 1A followed by immunoprecipitation of exogenous c-Myc proteins with anti-av-Myc12C. The half-life values were determined by a logarithmic analysis of the data obtained from densitometric scanning and the values shown are an average from two independent experiments. (B) CA46 cells were stably transfected with a plasmid encoding wild-type murine c-Myc as described in Materials and Methods (CA46/mycWT). c-Myc expression in untransfected CA46 and CA46/mycWT was analyzed by immunoprecipitation (IP) with either anti-(α)-MycFL or anti-av-Myc12C. (C) CA46 or CA46/mycWT cells were subjected to pulse-chase analysis followed by immunoprecipitation with either anti-MycFL (for CA46) or anti-av-Myc12C (for CA46/mycWT). endog., endogenous. The half-life values were determined as described for panel A.