title: Transcriptional activation of the anchoring protein SAP97 by heat shock factor (HSF)-1 stabilizes K(v) 1.5 channels in HL-1 cells.
abstract: OBJECTIVE
  The expression of voltage-dependent K(+) channels (K(v) ) 1.5 is regulated by members of the heat shock protein (Hsp) family. We examined whether the heat shock transcription factor 1 (HSF-1) and its inducer geranylgeranylacetone (GGA) could affect the expression of K(v) 1.5 channels and its anchoring protein, synapse associated protein 97 (SAP97).
  
  
  METHODS
  Transfected mouse atrial cardiomyocytes (HL-1 cells) and COS7 cells were subjected to luciferase reporter gene assay and whole-cell patch clamp. Protein and mRNA extracts were subjected to Western blot and quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  Heat shock of HL-1 cells induced expression of Hsp70, HSF-1, SAP97 and K(v) 1.5 proteins. These effects were reproduced by wild-type HSF-1. Both heat shock and expression of HSF-1, but not the R71G mutant, increased the SAP97 mRNA level. Small interfering RNA (siRNA) against SAP97 abolished HSF-1-induced increase of K(v) 1.5 and SAP97 proteins. A luciferase reporter gene assay revealed that the SAP97 promoter region (from -919 to -740) that contains heat shock elements (HSEs) was required for this induction. Suppression of SIRT1 function either by nicotinamide or siRNA decreased the level of SAP97 mRNA. SIRT1 activation by resveratrol had opposing effects. A treatment of the cells with GGA increased the level of SAP97 mRNA, K(v) 1.5 proteins and I(Kur) current, which could be modified with either resveratrol or nicotinamide.
  
  
  CONCLUSIONS
  HSF-1 induced transcription of SAP97 through SIRT1-dependent interaction with HSEs; the increase in SAP97 resulted in stabilization of K(v)1.5 channels. These effects were mimicked by GGA.
authors.affiliation: Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, Yonago, Japan.
authors.forename: Y K
authors.initials: YK
authors.lastname: Ting
authors.forename: K
authors.initials: K
authors.lastname: Morikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kurata
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.forename: U
authors.initials: U
authors.lastname: Bahrudin
authors.forename: E
authors.initials: E
authors.lastname: Mizuta
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: J
authors.initials: J
authors.lastname: Miake
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: A
authors.initials: A
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Murata
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: A
authors.initials: A
authors.lastname: Nakai
authors.forename: G
authors.initials: G
authors.lastname: Shiota
authors.forename: K
authors.initials: K
authors.lastname: Higaki
authors.forename: E
authors.initials: E
authors.lastname: Nanba
authors.forename: H
authors.initials: H
authors.lastname: Ninomiya
authors.forename: Y
authors.initials: Y
authors.lastname: Shirayoshi
authors.forename: I
authors.initials: I
authors.lastname: Hisatome
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D000074288:Discs Large Homolog 1 Protein; D004224:Diterpenes / Q000494:pharmacology; D051528:Guanylate Kinases; D006325:Heart Atria / Q000166:cytology / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D051666:Kv1.5 Potassium Channel / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D056564:Sirtuin 1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D000074288:Discs Large Homolog 1 Protein; D004224:Diterpenes; C000614189:Dlg1 protein, mouse; D000076249:Heat Shock Transcription Factors; D051666:Kv1.5 Potassium Channel; D008565:Membrane Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D051528:Guanylate Kinases; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; C031049:geranylgeranylacetone