title: Identification of a specific molecular repressor of the peroxisome proliferator-activated receptor gamma Coactivator-1 alpha (PGC-1alpha).
abstract: The nuclear co-activator PGC-1alpha is a pivotal regulator of numerous pathways controlling both metabolism and overall energy homeostasis. Inappropriate increases in PGC-1alpha activity have been linked to a number of pathological conditions including heart failure and diabetes mellitus. Previous studies (Puigserver, P., Adelmant, G., Wu, Z., Fan, M., Xu, J., O'Malley, B., and Spiegelman, B. M. (1999) Science 286, 1368-1371) have demonstrated an inhibitory domain within PGC-1alpha that limits transcriptional activity. Using this inhibitory domain in a yeast two-hybrid screen, we demonstrate that PGC-1alpha directly associates with the orphan nuclear receptor estrogen-related receptor-alpha (ERR-alpha). The binding of ERR-alpha to PGC-1alpha requires the C-terminal AF2 domain of ERR-alpha. PGC-1alpha and ERR-alpha have a similar pattern of expression in human tissues, with both being present predominantly in organs with high metabolic needs such as skeletal muscle and kidney. Similarly, we show that in mice physiological stimuli such as fasting coordinately induces PGC-1alpha and ERR-alpha transcription. We also demonstrate that under normal conditions PGC-1alpha is located within discrete nuclear speckles, whereas the expression of ERR-alpha results in PGC-1alpha redistributing uniformly throughout the nucleoplasm. Finally, we show that the expression of ERR-alpha can dramatically and specifically repress PGC-1alpha transcriptional activity. These results suggest a novel mechanism of transcriptional control wherein ERR-alpha can function as a specific molecular repressor of PGC-1alpha activity. In addition, our results suggest that other co-activators might also have specific repressors, thereby identifying another layer of combinatorial complexity in transcriptional regulation.
authors.affiliation: Laboratory of Molecular Biology, Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Masaru
authors.initials: M
authors.lastname: Ichida
authors.forename: Shino
authors.initials: S
authors.lastname: Nemoto
authors.forename: Toren
authors.initials: T
authors.lastname: Finkel
mesh_terms: D001665:Binding Sites; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D015723:Gene Library; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000235:genetics; D006706:Homeostasis; D006801:Humans; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010957:Plasmids; D016133:Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics; D011960:Receptors, Estrogen / Q000737:chemistry / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D000097983:ERRalpha Estrogen-Related Receptor
chemical_list: D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000097983:ERRalpha Estrogen-Related Receptor; C052130:GAL4 protein, S cerevisiae; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1