Urban renewal in the nucleus: is protein turnover by proteasomes absolutely required for nuclear receptor-regulated transcription?
The importance of the ubiquitin proteasome pathway in higher eukaryotes has been well established in cell cycle regulation, signal transduction, and cell differentiation, but has only recently been linked to nuclear hormone receptor-regulated gene transcription. Characterization of a number of ubiquitin proteasome pathway enzymes as coactivators and observations that several nuclear receptors are ubiquitinated and degraded in the course of their nuclear activities provide evidence that ubiquitin proteasome-mediated protein degradation plays an integral role in eukaryotic transcription. In addition to receptors, studies have revealed that coactivators are ubiquitinated and degraded via the proteasome. The notion that the ubiquitin proteasome pathway is involved in gene transcription is further strengthened by the fact that ubiquitin proteasome pathway enzymes are recruited to the promoters of target genes and that proteasome-dependent degradation of nuclear receptors is required for efficient transcriptional activity. These findings suggest that protein degradation is coupled with nuclear receptor coactivation activity. It is possible that the ubiquitin proteasome pathway modulates transcription by promoting remodeling and turnover of the nuclear receptor-transcription complex. In this review, we discus the possible role of the ubiquitin proteasome pathway in nuclear hormone receptor-regulated gene transcription.
Nawaz
Zafar
Z
Cancer Center, Creighton University, Omaha, Nebraska 68178, USA.
O'Malley
Bert W
BW
D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D051548:Histone Acetyltransferases; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D056920:Nuclear Receptor Coactivator 1; D046988:Proteasome Endopeptidase Complex; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
D009097:Multienzyme Complexes; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D025801:Ubiquitin; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex