Figure 4

Autocrine transforming growth factor (TGF)β signaling regulates protein phosphatase 2A (PP2A) expression in scleroderma (SSc) fibroblasts. (a) Normal dermal fibroblasts were pretreated with recombinant transforming growth factor β soluble receptor II (SRII) (10 ng/ml) for 1 h and then treated with 5 ng/ml of TGFβ for 24 h. Western blot analysis was used to determine PP2A levels. (b) Normal and (c) SSc dermal fibroblasts were treated with SRII for 24 h after serum deprivation. Cells were collected and total protein levels of PP2A catalytic subunit were analyzed by western blot. In SSc cells, cell lysates were also analyzed for phospho-extracellular signal-regulated kinase (ERK)1/2 and type 1 collagen. β Actin was used as a loading control. (d) Bar graph shows quantification of PP2A protein expression after treatment of SSc fibroblasts with SRII; *P < 0.05.