Figure 3
Stat3/ErbB-2/PR transcriptional complex induced by progestins in breast cancer. PR activated by progestins induces the phosphorylation of ErbB-2 at Tyr 1222 and Tyr 877 (1). ErbB-2 activated by a nongenomic PR action stimulates Stat3 phosphorylation (2) (Beguelin et al. 2010). ErbB-2 (3) and Stat3 (4) then translocate to the nucleus where they assemble a transcriptional complex at the Stat3 response element (GAS sites) of the cyclin D1 promoter, in which ErbB-2 acts as a coactivator of Stat3. PR is also loaded on the Stat3/ErbB-2 complex (5).
