FIG. 6.

Model depicting the interrelationships elucidated in the present study between ERα, ERK2, and CREB1 in the hormonal regulation of gene expression and cell proliferation. Our findings reveal rapid activation of ERK2 and CREB1 (red stars) in response to estrogen and their colocalization with ERα at enhancer binding sites. ERK2 and CREB1 collaborate with ERα in regulating hormone stimulation of proliferation and of cell cycle-related genes. The findings indicate that ERK2 has not only a signaling function but also a nuclear role at chromatin in integrating with and supporting the actions of this nuclear hormone receptor. See the text for details. CoA, coactivator.