Frog α- and β-ryanodine receptors provide distinct intracellular Ca2+ signals in a myogenic cell line

Taku Kashiyama, Takashi Murayama, Erika Suzuki, Paul D. Allen, Yasuo Ogawa

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Background: In frog skeletal muscle, two ryanodine receptor (RyR) isoforms, α-RyR and β-RyR, are expressed in nearly equal amounts. However, the roles and significance of the two isoforms in excitation-contraction (E-C) coupling remains to be elucidated. Methodology/Principal Findings: In this study, we expressed either or both α-RyR and β-RyR in 1B5 RyR-deficient myotubes using the herpes simplex virus 1 helper-free amplicon system. Immunological characterizations revealed that α-RyR and β-RyR are appropriately expressed and targeted at the junctions in 1B5 myotubes. In Ca2+ imaging studies, each isoform exhibited caffeine-induced Ca2+ transients, an indicative of Ca2+-induced Ca2+ release (CICR). However, the fashion of Ca2+ release events was fundamentally different: α-RyR mediated graded and sustained Ca2+ release observed uniformly throughout the cytoplasm, whereas β-RyR supported all-or-none type regenerative Ca2+ oscillations and waves. α-RyR but not β-RyR exhibited Ca2+ transients triggered by membrane depolarization with high [K+]o that were nifedipine-sensitive, indicating that only α-RyR mediates depolarization-induced Ca2+ release. Myotubes co-expressing α-RyR and β-RyR demonstrated high [K+]o-induced Ca2+ transients which were indistinguishable from those with myotubes expressing α-RyR alone. Furthermore, procaine did not affect the peak height of high [K+]o-induced Ca2+ transients, suggesting minor amplification of Ca2+ release by β-RyR via CICR in 1B5 myotubes. Conclusions/Significance: These findings suggest that α-RyR and β-RyR provide distinct intracellular Ca2+ signals in a myogenic cell line. These distinct properties may also occur in frog skeletal muscle and will be important for E-C coupling.

Original languageEnglish (US)
Article numbere11526
JournalPLoS One
Volume5
Issue number7
DOIs
StatePublished - 2010
Externally publishedYes

Fingerprint

ryanodine receptors
Ryanodine Receptor Calcium Release Channel
Anura
frogs
Cells
cell lines
calcium
Cell Line
Skeletal Muscle Fibers
Excitation Contraction Coupling
Protein Isoforms
Depolarization
Muscle
skeletal muscle
Skeletal Muscle
procaine
Human herpesvirus 1

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Frog α- and β-ryanodine receptors provide distinct intracellular Ca2+ signals in a myogenic cell line. / Kashiyama, Taku; Murayama, Takashi; Suzuki, Erika; Allen, Paul D.; Ogawa, Yasuo.

In: PLoS One, Vol. 5, No. 7, e11526, 2010.

Research output: Contribution to journalArticle

Kashiyama, Taku ; Murayama, Takashi ; Suzuki, Erika ; Allen, Paul D. ; Ogawa, Yasuo. / Frog α- and β-ryanodine receptors provide distinct intracellular Ca2+ signals in a myogenic cell line. In: PLoS One. 2010 ; Vol. 5, No. 7.
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