A subfamily of RNA-binding DEAD-box proteins acts as an estrogen receptor alpha coactivator through the N-terminal activation domain (AF-1) with an RNA coactivator, SRA.
One class of the nuclear receptor AF-2 coactivator complexes contains the SRC-1/TIF2 family, CBP/p300 and an RNA coactivator, SRA. We identified a subfamily of RNA-binding DEAD-box proteins (p72/p68) as a human estrogen receptor alpha (hER alpha) coactivator in the complex containing these factors. p72/p68 interacted with both the AD2 of any SRC-1/TIF2 family protein and the hER alpha A/B domain, but not with any other nuclear receptor tested. p72/p68, TIF2 (SRC-1) and SRA were co-immunoprecipitated with estrogen-bound hER alpha in MCF7 cells and in partially purified complexes associated with hER alpha from HeLa nuclear extracts. Estrogen induced co-localization of p72 with hER alpha and TIF2 in the nucleus. The presence of p72/p68 potentiated the estrogen-induced expression of the endogenous pS2 gene in MCF7 cells. In a transient expression assay, a combination of p72/p68 with SRA and one TIF2 brought an ultimate synergism to the estrogen-induced transactivation of hER alpha. These findings indicate that p72/p68 acts as an ER subtype-selective coactivator through ER alpha AF-1 by associating with the coactivator complex to bind its AF-2 through direct binding with SRA and the SRC-1/TIF2 family proteins.
Watanabe
M
M
Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0033, Japan.
Yanagisawa
J
J
Kitagawa
H
H
Takeyama
K
K
Ogawa
S
S
Arao
Y
Y
Suzawa
M
M
Kobayashi
Y
Y
Yano
T
T
Yoshikawa
H
H
Masuhiro
Y
Y
Kato
S
S
D020816:Amino Acid Motifs; D002451:Cell Compartmentation; D004958:Estradiol / Q000378:metabolism; D020847:Estrogen Receptor Modulators / Q000378:metabolism*; D047628:Estrogen Receptor alpha; D004967:Estrogens / Q000378:metabolism; D006367:HeLa Cells; D051548:Histone Acetyltransferases; D006801:Humans; D008024:Ligands; D056920:Nuclear Receptor Coactivator 1; D051958:Nuclear Receptor Coactivator 2; D011485:Protein Binding; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D011506:Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D004967:Estrogens; D008024:Ligands; C498001:NCOA2 protein, human; D051958:Nuclear Receptor Coactivator 2; D011506:Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011960:Receptors, Estrogen; C051838:TFF1 protein, human; D014157:Transcription Factors; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; C405423:steroid receptor RNA activator; D004958:Estradiol; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1