Differential modulation of SERCA2 isoforms by calreticulin

Linu M. John, James D. Lechleiter, Patricia Camacho

Research output: Contribution to journalArticle

175 Scopus citations

Abstract

In Xenopus laevis oocytes, overexpression of calreticulin suppresses inositol 1,4,5-trisphosphate-induced Ca2+ oscillations in a manner consistent with inhibition of Ca2+ uptake into the endoplasmic reticulum. Here we report that the alternatively spliced isoforms of the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA)2 gene display differential Ca2+ wave properties and sensitivity to modulation by calreticulin. We demonstrate by glucosidase inhibition and site-directed mutagenesis that a putative glycosylated residue (N1036) in SERCA2b is critical in determining both the selective targeting of calreticulin to SERCA2b and isoform functional differences. Calreticulin belongs to a novel class of lectin ER chaperones that modulate immature protein folding. In addition to this role, we suggest that these chaperones dynamically modulate the conformation of mature glycoproteins, thereby affecting their function.

Original languageEnglish (US)
Pages (from-to)963-973
Number of pages11
JournalJournal of Cell Biology
Volume142
Issue number4
DOIs
StatePublished - Aug 24 1998

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Keywords

  • Ca waves
  • Ca-ATPases
  • Calreticulin
  • Confocal imaging
  • ER lectin chaperones

ASJC Scopus subject areas

  • Cell Biology

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