Figure 3.

CaMKIV kinase activity increases during C2C12 differentiation. (A) C2C12 cells were cotransfected with His-CaMKIV along with either an empty vector or a constitutively active CaMKK (positive control), and cells were harvested at times indicated (CaMKK, DM 24 h). After normalization of CaMKIV level by Western blot, the kinase activity of the CaMKIV toward syntide in each sample was determined. Fold activation: the ratio of the kinase activity in DM over that in GM. The experiment was done twice and the mean ± SD is shown. A two-sample t test was performed with p < 0.05 considered statistically significant. (B) C2C12 cells were transfected with HDAC5-GFP. Cells were fixed at times indicated and visualized under fluorescent microscope. (C) The average ratio of cells containing HDAC5-GFP in the cytoplasm over those with green colors (i.e., total transfected cells) from five random fields in each sample from B is plotted.