Troponin I converts the skeletal muscle ryanodine receptor into a rectifying calcium release channel

Magdolna Varsányi, Sándor Sárközi, Csaba Szegedi, Anke Herzog, István Jóna

Research output: Contribution to journalArticle

2 Citations (Scopus)


The goal of our present studies has been to find novel ryanodine receptor (RyR1) interacting polypeptides that modulate the channel activity from the luminal side of RyR1. Using K+ as charge carrier for recording of single channel events here we demonstrate a very unexpected observation that troponin I substantially alters RyR's gating behavior, and that RyR1 in association with troponin I becomes a rectifying Ca2+ release channel. Troponin I rapidly locks the RyR1 in a non-conducting state only at a negative holding potential, and only when applied to the luminal side; switching to a positive holding potential results in the channel returning to its original activity, immediately. A hypothesis is proposed to account for how an intraluminally located, positively charged molecule might function as a RyR1 regulator under physiological conditions.

Original languageEnglish
Pages (from-to)155-158
Number of pages4
JournalFEBS letters
Issue number1-3
Publication statusPublished - Mar 27 2002



  • Calcium release
  • Rectifying channel
  • Ryanodine receptor
  • Skeletal muscle
  • Troponin I
  • Yeast two-hybrid screen

ASJC Scopus subject areas

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

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