Modulation of H+,K+-ATPase activity by the molecular chaperone ERp57 highly expressed in gastric parietal cells

Takuto Fujii, Shun Ya Awaka, Yuji Takahashi, Kyosuke Fujita, Hiroshi Tsuji, Takahiro Shimizu, Tomoharu Gomi, Kazuhiro Tsukada, Hideki Sakai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

ERp57 is a ubiquitous ER chaperone that has disulfide isomerase activity. Here, we found that both ERp57 and gastric H+,K+-ATPase are expressed in a sample derived from the apical canalicular membranes of parietal cells. Overexpression of ERp57 in HEK293 cells stably expressing H +,K+-ATPase significantly increased the ATPase activity without changing the expression level of H+,K+-ATPase. Interestingly, overexpression of a catalytically inactive mutant of ERp57 (C57S/C60S/C406S/C409S) in the cells also increased H+,K +-ATPase activity. In contrast, knockdown of endogenous ERp57 in H+,K+-ATPase-expressing cells significantly decreased ATPase activity without changing the expression level of H+,K +-ATPase. Overexpression and knockdown of ERp57 had no significant effect on the expression and function of Na+,K+-ATPase. These results suggest that ERp57 positively regulates H+,K +-ATPase activity apart from its chaperoning function.

Original languageEnglish
Pages (from-to)3898-3905
Number of pages8
JournalFEBS Letters
Volume587
Issue number24
DOIs
StatePublished - 2013/12/11

Keywords

  • ERp57
  • Gastric mucosa
  • H,K-ATPase
  • Molecular chaperone
  • Parietal cell

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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