Figure 2. Progesterone receptor-B, but not progesterone receptor-A, and estrogen receptor-α participate in membrane-tethered protein complexes capable of rapidly activating c-Src and MAPKs.
Progesterone/PR and estrogen/ER transactivate EGFR and/or ErbB2; phosphorylated steroid hormone receptors and signaling molecules, including protein kinases and surface receptors, enter the nucleus and participate in transcription complexes at selected gene promoters.
E2: Estradiol; EGFR: EGF receptor; ER: Estrogen receptor; P: Phosphorylation; P4: Progesterone; PR: Progesterone receptor; Shc: Src homology domain II containing.