Ligand-selective potentiation of rat mineralocorticoid receptor activation function 1 by a CBP-containing histone acetyltransferase complex.
The rat mineralocorticoid receptor (MR) has two activation functions in distinct regions of the A/B domain, designated activation function 1a (AF-1a; amino acids 1 to 169) and AF-1b (amino acids 451 to 600). Since the p160 family protein TIF2, a known component of the AF-2 coactivator complex, potentiates the transactivation function of AF-1b but not that of AF-1a, it is likely that some other, novel protein complex interacts with the AF-1a region. Therefore, we attempted to identify such coactivator complexes from HeLa nuclear extracts by biochemical purification using a glutathione S-transferase-MR AF-1a fusion protein. Purified AF-1a region-interacting proteins were found to contain RNA helicase A (RHA) and CBP. Further analysis showed that RHA interacted with the AF-1a region directly and then recruited a complex with histone acetyltransferase (HAT) activity that contained CBP. For full-length MR, aldosterone, but not hydrocortisone, was found to induce the binding of RHA/CBP complexes to the AF-1a region, as well as to allow the cooperative potentiation of MR transcriptional activity by RHA and CBP. In addition, a chromatin immunoprecipitation assay showed that aldosterone-bound MR, but not hydrocortisone-bound MR, recruited RHA/CBP complexes to native MR target gene promoters. Our results suggested that an altered conformation of the A/B region induced by aldosterone, but not hydrocortisone, might determine the accessibility of MR AF-1a to RHA/CBP complexes.
Kitagawa
Hirochika
H
Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Japan.
Yanagisawa
Junn
J
Fuse
Hiroaki
H
Ogawa
Satoko
S
Yogiashi
Yoshiko
Y
Okuno
Atsuro
A
Nagasawa
Hiromichi
H
Nakajima
Toshihiro
T
Matsumoto
Toshio
T
Kato
Shigeaki
S
D000123:Acetyltransferases / Q000378:metabolism*; D000450:Aldosterone / Q000378:metabolism; D000818:Animals; D001324:Autoantigens / Q000378:metabolism; D002460:Cell Line; D053487:DEAD-box RNA Helicases; D006367:HeLa Cells; D051548:Histone Acetyltransferases; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008024:Ligands; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020365:RNA Helicases / Q000378:metabolism; D051381:Rats; D018161:Receptors, Mineralocorticoid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
D001324:Autoantigens; D008024:Ligands; D046911:Macromolecular Substances; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D018161:Receptors, Mineralocorticoid; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D000450:Aldosterone; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases; D006854:Hydrocortisone