Figure 4. CAMKIIγ stabilizes the c-Myc protein.
(A) H9 cells with indicated viral infection were treated with 50 μM CHX for indicated times. The c-Myc protein levels were analyzed by western blot analysis with GAPDH as loading control (left). Protein levels were measured with the densitometric intensity. C-Myc levels were quantified relative to GAPDH levels and graphed as percent c-Myc protein remaining after CHX treatment (right).
(B) Summary of c-Myc half-lives in four TCL cell lines. Data represent the mean ± s.d. for four TCL cell lines. **p < 0.01.
(C) Protein detected by autoradiography after a 35S-methionine pulse-chase from indicated cell lines at indicated time points (left). The rate of degradation of endogenous c-Myc for each cell line was represented in the graph by best-fit exponential lines (right).
(D) Summary of mean half-life ± s.d. for c-Myc calculated from three independent experiments for each cell type of H9 cells.
(E) Pulse-chase analysis of c-Myc using HT-TMR system in indicated cell lines transfected with HT-c-Myc. The HT-TMR ligand-labeled HT-c-Myc was visualized with a fluoro-image analyzer (the top sub-panel) and the total expression of HT-c-Myc was analyzed by western blot analysis with GAPDH as loading control (left). The relative amount of HT-TMR ligand-labeled HT-c-Myc was measured with the densitometric intensity of each band (right).
Half-lives of c-Myc were calculated from exponential line equations and were shown for each cell type. Pulse-chase results shown here were representative of three independent experiments. See also Figure S4.