F. Lhorset et al., RIP-140 INTERACTS WITH MULTIPLE NUCLEAR RECEPTORS BY MEANS OF 2 DISTINCT SITES, Molecular and cellular biology, 16(11), 1996, pp. 6029-6036
We have characterized two distinct binding sites, called site 1 and si
te 2, in the nuclear protein RIP-140 which interact with the ligand bi
nding domain of the estrogen receptor both in solution and when the re
ceptor is bound to DNA, Both sites are capable of independently intera
cting with other nuclear receptors, including the thyroid hormone and
retinoic acid receptors, but they are not identical since the interact
ion with retinoid X receptor is mediated primarily by site 1. The inte
raction is enhanced by agonists but not by antagonists, and the in vit
ro binding activities to a number of mutant receptors correlate with t
heir abilities to stimulate transcription in vivo. When RIP-140 is fus
ed to heterologous DNA binding domains, it is able to stimulate the tr
anscription of reporter genes in both yeast and mammalian cells. Thus,
RIP-140 is likely to function as a bridging protein between receptors
and the basal transcription machinery and thereby stimulate the trans
cription of target genes.