| First Author | Saito Y | Year | 2014 |
| Journal | Exp Cell Res | Volume | 327 |
| Issue | 1 | Pages | 163-70 |
| PubMed ID | 25088258 | Mgi Jnum | J:217560 |
| Mgi Id | MGI:5614536 | Doi | 10.1016/j.yexcr.2014.07.023 |
| Citation | Saito Y, et al. (2014) Nmi interacts with Hsp105beta and enhances the Hsp105beta-mediated Hsp70 expression. Exp Cell Res 327(1):163-70 |
| abstractText | The mammalian stress protein Hsp105alpha is expressed constitutively and is further induced under stress conditions, whereas the alternative spliced form, Hsp105beta is only expressed during mild heat shock. We previously reported that Hsp105alpha is localized mainly in the cytoplasm, whereas Hsp105beta is localized in the nucleus. Consistent with the different localization of these proteins, Hsp105beta but not Hsp105alpha induces the expression of the major stress protein Hsp70. We here identified N-myc and Stat interactor (Nmi), as an Hsp105beta-binding protein by yeast two-hybrid screening. Immunoprecipitation and pull-down assay showed that Nmi interacts with Hsp105beta in vivo and in vitro. Luciferase reporter gene assay and Western blotting showed that Nmi enhanced both the Hsp105beta-induced phosphorylation of Stat3 and the Hsp105beta-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 Hsp105beta, is suppressed by knockdown of endogenous Nmi. These results suggest that Nmi has a role as a positive regulator of Hsp105beta-mediated hsp70 gene expression along the Stat3 signaling pathway. |
