Fig. 1
p38 MAPK activity is rhythmic in SCN and fibroblast cultures. a Representative western blots and densitometric analyses of p38 MAPK activation in WT mouse SCN (n = 3) and fibroblast (n = 4) cultures harvested following serum shock at 4-h intervals for 2 days. Western blots depict immunoreactive signal for phospho-p38 MAPK (pp38), total p38 MAPK (p38) and β-actin in the same samples. Graphs on the right depict the average immunoreactive signal (pp38 or p38) normalized to β-actin obtained from 3 to 4 independent sets of samples. The pp38 MAPK (black squares) signal was rhythmic in SCN cells and fibroblasts as confirmed by statistical best fit to a sine wave (p < 0.05; n = 3 for SCN cells, and n = 4 for fibroblasts, ± SEM). Total p38 protein (gray triangles) was arrhythmic in SCN and fibroblast cultures as confirmed by statistical best fit to a line (p < 0.05; n = 3 for SCN cells, and n = 4 for fibroblasts, ± SEM). b Representative western blots and densitometry examining p38 MAPK activation in clock-disrupted Per1ldc/Per2ldc SCN (n = 3) and fibroblast (n = 5) cultures as described in A. The ratios of pp38/β-actin (black circles) and p38/β-actin (gray triangles) signal were arrhythmic in SCN cells and fibroblasts as confirmed by statistical best fit to a line (p < 0.05; n = 3 for SCN cells, and n = 5 for fibroblasts, ± SEM). Pictures of full gels are shown in Additional file 1