Fig. 3

PRRG4 enhances STAT3 activation via Src. A Knockdown of PRRG4 decreases STAT3 activation in breast cancer cells. B PRRG4 overexpression enhances STAT3 activation in breast cancer cells. C PRRG4 via its WW domain binding motif LPSY189 promotes STAT3 activation through Src activation in breast cancer cells. MDA-MB-231 cells with vector, PRRG4-WT, and PRRG4-Y189A mutant were treated with vehicle or Src inhibitor Dasatinib (40 nM for MDA-MB-231, and 80 nM for HCC1954) for 2 h before being subjected to immunoblotting. p-Stat3 and p-Src levels were quantified and normalized to corresponding β-actin levels, which were presented as fold changes relative to controls that were set to 1. *p < 0.05, **p < 0.01, ***p < 0.001