Figure 3

Increased extracellular signal-regulated kinase (ERK)1/2 phosphorylation and decreased protein phosphatase 2A (PP2A) expression in scleroderma (SSc) fibroblasts. Dermal fibroblasts obtained from SSc patients and matched controls were grown to confluence and then serum starved for 24 h. Cells were collected and in (a) the levels of ERK1/2 phosphorylation were analyzed by western blot. In (b), the mRNA levels of the PP2A catalytic subunits α and β were analyzed using quantitative PCR. The mRNA values were normalized relative to matched controls (arbitrarily set as 1) and means ± standard error of the mean (SEM) of five independent experiments are shown (*P < 0.01). (c) The total protein levels of the PP2A catalytic subunit were measured by western blot. β Actin was used as a loading control.