Molecular Biology Commons^™

Actr/Aib1 Functions As An E2f1 Coactivator To Promote Breast Cancer Cell Proliferation And Antiestrogen Resistance, Maggie C. Louie, June X. Zou, Alina Rabinovich, Hong-Wu Chen

Collected Faculty and Staff Scholarship

Overexpression or amplification of ACTR (also named AIB1, RAC3, p/CIP, TRAM-1, and SRC-3), a member of the p160 family of coactivators for nuclear hormone receptors, has been frequently detected in multiple types of human tumors, including breast cancer. However, its role in cancer cell proliferation and the underlying mechanism are unclear. Here, we show that overexpression of ACTR not only enhances estrogen-stimulated cell proliferation but also, more strikingly, completely negates the cell cycle arrest effect by tamoxifen and pure antiestrogens. Unexpectedly, we found that ACTR directly interacts, through its N-terminal domain, with E2F1 and is recruited to E2F target gene …