FIGURE 6.

TGF-β-mediated Stat3 phosphorylation requires JAK1. CFSC-2G (CFSC) cells were transfected with JAK1, JAK2, or Tyk2 siRNA and subsequently exposed to 5 ng/ml TGF-β1 for 2 h. Knockdown of JAK1 blunted Stat3 phosphorylation and resulted in reduced CTGF expression. Silencing JAK2 and Tyk2 had no influence on this process. CTGF and GAPDH expression was quantified, and data are means ± S.E.; p < 0.01 indicates the statistical significance. Knockdown of JAKs was verified at the RNA level by semiquantitative PCR. ut, untreated; siCo, siControl; n.s., not significant.