title: Nuclear localization and regulation of Id protein through an E protein-mediated chaperone mechanism.
abstract: Members of the Id family of helix-loop-helix proteins function as negative regulators of DNA binding, E protein, helix-loop-helix transcription factors in the control of cell growth, differentiation, and development. By using transient transfection analysis of COS cells, we show that in the absence of its E protein target, the Id3 protein is localized exclusively to the cytoplasm/perinuclear region. Co-transfection with E protein (E47) results in nuclear translocation of the Id3 protein, a process requiring both a functional Id helix-loop-helix dimerization domain and an E protein nuclear localization signal. Id3 that is associated with E protein displays an extended half-life, while the E protein itself is more rapidly turned over. These observations demonstrate that E protein, by nuclear chaperoning Id, can regulate the available cellular pool of its own inhibitory partner.
authors.affiliation: Cancer Research Campaign Department of Gene Regulation, Paterson Institute for Cancer Research, Christie Hospital National Health Service Trust, Wilmslow Road, Manchester M20 9BX, United Kingdom.
authors.forename: R W
authors.initials: RW
authors.lastname: Deed
authors.forename: S
authors.initials: S
authors.lastname: Armitage
authors.forename: J D
authors.initials: JD
authors.lastname: Norton
mesh_terms: D000818:Animals; D019556:COS Cells; D002451:Cell Compartmentation; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D051796:Inhibitor of Differentiation Proteins; D018832:Molecular Chaperones / Q000378:metabolism; D009363:Neoplasm Proteins; D011233:Precipitin Tests; D011485:Protein Binding; D011994:Recombinant Proteins; D013329:Structure-Activity Relationship; D051820:TCF Transcription Factors; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
chemical_list: D004268:DNA-Binding Proteins; D051796:Inhibitor of Differentiation Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; D051820:TCF Transcription Factors; C544912:TCF7L1 protein, human; D058125:Transcription Factor 7-Like 1 Protein; D014157:Transcription Factors; C075640:ID3 protein, human