title: Nmi interacts with Hsp105β and enhances the Hsp105β-mediated Hsp70 expression.
abstract: The mammalian stress protein Hsp105α is expressed constitutively and is further induced under stress conditions, whereas the alternative spliced form, Hsp105β is only expressed during mild heat shock. We previously reported that Hsp105α is localized mainly in the cytoplasm, whereas Hsp105β is localized in the nucleus. Consistent with the different localization of these proteins, Hsp105β but not Hsp105α induces the expression of the major stress protein Hsp70. We here identified N-myc and Stat interactor (Nmi), as an Hsp105β-binding protein by yeast two-hybrid screening. Immunoprecipitation and pull-down assay showed that Nmi interacts with Hsp105β in vivo and in vitro. Luciferase reporter gene assay and Western blotting showed that Nmi enhanced both the Hsp105β-induced phosphorylation of Stat3 and the Hsp105β-induced activation of the hsp70 promoter in a manner that is dependent on the Stat3-binding site, which results in an increase in Hsp70 protein levels. Most importantly, mild heat shock-induced Hsp70 expression, which is dependent on Hsp105β, is suppressed by knockdown of endogenous Nmi. These results suggest that Nmi has a role as a positive regulator of Hsp105β-mediated hsp70 gene expression along the Stat3 signaling pathway.
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan. Electronic address: ysaito@mb.kyoto-phu.ac.jp.
authors.forename: Youhei
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Yukawa
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Matozaki
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Mikami
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamagami
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamagishi
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kuga
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Hatayama
authors.affiliation: Department of Biochemistry and Molecular Biology, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan. Electronic address: nakayama@mb.kyoto-phu.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D015870:Gene Expression / Q000235:genetics; D050957:HSP110 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; C099927:NMI protein, human; D050796:STAT3 Transcription Factor
keywords: Hsp105; Hsp70; Hsp70 inducer; Nmi; Stat3; Yeast two-hybrid screening