Nuclear and cytoplasmic interaction of pRb2/p130 and ER-beta in MCF-7 breast cancer cells.
Estrogens exhibit important biological functions and influence several pathological processes of hormone-dependent diseases. The biological actions of estrogens require their interaction with two estrogen receptors (ER-alpha and ER-beta), which are ligand-dependent transcription factors. ER-alpha and ER-beta exhibit distinct tissue expression patterns as well as show different patterns of gene regulation. In addition, it has been suggested that ER-beta works as a counter partner of ER-alpha through inhibition of the transactivating functions of ER-alpha. For instance, ER-beta seems to play a different role in breast tumorigenesis than ER-alpha, as ER-beta decreased expression in breast cancer has been correlated with bad prognosis. Biological activities of ER-alpha and ER-beta could be controlled by a number of interacting proteins such as activators/inhibitors, ligand binding and kinases. We have previously reported that pRb2/p130, retinoblastoma related protein, could be involved in the silencing of ER-alpha gene during breast tumorigenesis. Here, we report that ER-beta and pRb2/p130 proteins co-immunoprecipitate in both nucleus and cytoplasm of MCF-7 breast cancer cells. Our hypothesis is that the interaction of pRb2/130 with ER-beta may have a functional significance in regulating ER-beta activity.
Macaluso
M
M
Sbarro Institute for Cancer Research and Molecular Medicine, Center of Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
Montanari
M
M
Noto
P B
PB
Gregorio
V
V
Surmacz
E
E
Giordano
A
A
D000595:Amino Acid Sequence; D001943:Breast Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D050717:Retinoblastoma-Like Protein p130 / Q000378:metabolism*
D047629:Estrogen Receptor beta; D050717:Retinoblastoma-Like Protein p130