Fig. 4.

CaMKIV derepresses the inhibitory effect of PHB2 on MEF2 through phosphorylation. C2C12 cells were co-transfected with 3xMEF2-luc together with an empty vector, wild type or mutant PHB2 (A) and with CaMKIVca in various combinations as indicated (B). After 36 h of growth in GM and 24 h in DM, cells were harvested and the luciferase activity determined. The data denote fold changes in the luciferase activity of samples transfected with PHB2 or CaMKIVca alone or combination versus that transfected with an empty vector. The experiments were performed in triplicate and independently three times with similar results. The results from a representative experiment are presented. *p < 0.001, compared to the sample transfected with an empty vector; N.S, not significant compared to the sample transfected with CaMKIVca alone; ** p < 0.001, compared to the sample transfected with CaMKIVca alone or PHB-wt and CaMKIVca combination. Abbreviations: wt, wild type; mut, mutant; ca, constitutively active; vec, an empty vector.