Enhanced excitation-coupled calcium entry in myotubes is associated with expression of RyR1 malignant hyperthermia mutations

Tianzhong Yang, Paul D. Allen, Isaac N Pessah, Jose R. Lopez

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Myotubes expressing wild type RyR1 (WT) or RyR1 with one of three malignant hyperthermia mutations R615C, R2163C, and T4826I (MH) were exposed sequentially to 60 mM KCl in Ca2+-replete and Ca2+-free external buffers (Ca+ and Ca-, respectively) with 3 min of rest between exposures. Although the maximal peak amplitude of the Ca2+ transients during K+ depolarization was similar for WT and MH in both external buffers, the rate of decay of the sustained phase of the transient during K+ depolarization (decay rate) in Ca+ was 50% slower for MH. This difference was eliminated in Ca-, and the relative decay rates were faster for both genotypes than in Ca+. The integrated Ca2+ transient in Ca- compared with Ca+ was reduced by 50-60% for MH and 20% for WT. The decay rate was not affected by [K+] x [Cl-] product or NiCl2 (2 mM) supplementation of Ca-. The addition of La2+ (0.1mM), or SKF 96365 (20 μM) to Ca+ significantly accelerated decay rates for both WT and MH, but their effect was significantly greater in MH. Nifedipine (1 μM) had no effect, suggesting that the mechanism for this difference was not a reduction in L-type Ca2+ channel Ca2+ current. These data strongly suggest: 1) the decay rate in skeletal myotubes is related in part to Ca 2+ entry through the ECCE channel; 2) the MH mutations enhance ECCE compared with wild type; and 3) the increased Ca2+ entry might play a significant role in the pathophysiology of MH.

Original languageEnglish (US)
Pages (from-to)37471-37478
Number of pages8
JournalJournal of Biological Chemistry
Volume282
Issue number52
DOIs
StatePublished - Dec 28 2007

Fingerprint

Malignant Hyperthermia
Ryanodine Receptor Calcium Release Channel
Skeletal Muscle Fibers
Calcium
Mutation
1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole
Depolarization
Buffers
Nifedipine
Genotype

ASJC Scopus subject areas

  • Biochemistry

Cite this

Enhanced excitation-coupled calcium entry in myotubes is associated with expression of RyR1 malignant hyperthermia mutations. / Yang, Tianzhong; Allen, Paul D.; Pessah, Isaac N; Lopez, Jose R.

In: Journal of Biological Chemistry, Vol. 282, No. 52, 28.12.2007, p. 37471-37478.

Research output: Contribution to journalArticle

@article{a17880e3cf2a4104ac5a154475577332,
title = "Enhanced excitation-coupled calcium entry in myotubes is associated with expression of RyR1 malignant hyperthermia mutations",
abstract = "Myotubes expressing wild type RyR1 (WT) or RyR1 with one of three malignant hyperthermia mutations R615C, R2163C, and T4826I (MH) were exposed sequentially to 60 mM KCl in Ca2+-replete and Ca2+-free external buffers (Ca+ and Ca-, respectively) with 3 min of rest between exposures. Although the maximal peak amplitude of the Ca2+ transients during K+ depolarization was similar for WT and MH in both external buffers, the rate of decay of the sustained phase of the transient during K+ depolarization (decay rate) in Ca+ was 50{\%} slower for MH. This difference was eliminated in Ca-, and the relative decay rates were faster for both genotypes than in Ca+. The integrated Ca2+ transient in Ca- compared with Ca+ was reduced by 50-60{\%} for MH and 20{\%} for WT. The decay rate was not affected by [K+] x [Cl-] product or NiCl2 (2 mM) supplementation of Ca-. The addition of La2+ (0.1mM), or SKF 96365 (20 μM) to Ca+ significantly accelerated decay rates for both WT and MH, but their effect was significantly greater in MH. Nifedipine (1 μM) had no effect, suggesting that the mechanism for this difference was not a reduction in L-type Ca2+ channel Ca2+ current. These data strongly suggest: 1) the decay rate in skeletal myotubes is related in part to Ca 2+ entry through the ECCE channel; 2) the MH mutations enhance ECCE compared with wild type; and 3) the increased Ca2+ entry might play a significant role in the pathophysiology of MH.",
author = "Tianzhong Yang and Allen, {Paul D.} and Pessah, {Isaac N} and Lopez, {Jose R.}",
year = "2007",
month = "12",
day = "28",
doi = "10.1074/jbc.M701379200",
language = "English (US)",
volume = "282",
pages = "37471--37478",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "52",

}

TY - JOUR

T1 - Enhanced excitation-coupled calcium entry in myotubes is associated with expression of RyR1 malignant hyperthermia mutations

AU - Yang, Tianzhong

AU - Allen, Paul D.

AU - Pessah, Isaac N

AU - Lopez, Jose R.

PY - 2007/12/28

Y1 - 2007/12/28

N2 - Myotubes expressing wild type RyR1 (WT) or RyR1 with one of three malignant hyperthermia mutations R615C, R2163C, and T4826I (MH) were exposed sequentially to 60 mM KCl in Ca2+-replete and Ca2+-free external buffers (Ca+ and Ca-, respectively) with 3 min of rest between exposures. Although the maximal peak amplitude of the Ca2+ transients during K+ depolarization was similar for WT and MH in both external buffers, the rate of decay of the sustained phase of the transient during K+ depolarization (decay rate) in Ca+ was 50% slower for MH. This difference was eliminated in Ca-, and the relative decay rates were faster for both genotypes than in Ca+. The integrated Ca2+ transient in Ca- compared with Ca+ was reduced by 50-60% for MH and 20% for WT. The decay rate was not affected by [K+] x [Cl-] product or NiCl2 (2 mM) supplementation of Ca-. The addition of La2+ (0.1mM), or SKF 96365 (20 μM) to Ca+ significantly accelerated decay rates for both WT and MH, but their effect was significantly greater in MH. Nifedipine (1 μM) had no effect, suggesting that the mechanism for this difference was not a reduction in L-type Ca2+ channel Ca2+ current. These data strongly suggest: 1) the decay rate in skeletal myotubes is related in part to Ca 2+ entry through the ECCE channel; 2) the MH mutations enhance ECCE compared with wild type; and 3) the increased Ca2+ entry might play a significant role in the pathophysiology of MH.

AB - Myotubes expressing wild type RyR1 (WT) or RyR1 with one of three malignant hyperthermia mutations R615C, R2163C, and T4826I (MH) were exposed sequentially to 60 mM KCl in Ca2+-replete and Ca2+-free external buffers (Ca+ and Ca-, respectively) with 3 min of rest between exposures. Although the maximal peak amplitude of the Ca2+ transients during K+ depolarization was similar for WT and MH in both external buffers, the rate of decay of the sustained phase of the transient during K+ depolarization (decay rate) in Ca+ was 50% slower for MH. This difference was eliminated in Ca-, and the relative decay rates were faster for both genotypes than in Ca+. The integrated Ca2+ transient in Ca- compared with Ca+ was reduced by 50-60% for MH and 20% for WT. The decay rate was not affected by [K+] x [Cl-] product or NiCl2 (2 mM) supplementation of Ca-. The addition of La2+ (0.1mM), or SKF 96365 (20 μM) to Ca+ significantly accelerated decay rates for both WT and MH, but their effect was significantly greater in MH. Nifedipine (1 μM) had no effect, suggesting that the mechanism for this difference was not a reduction in L-type Ca2+ channel Ca2+ current. These data strongly suggest: 1) the decay rate in skeletal myotubes is related in part to Ca 2+ entry through the ECCE channel; 2) the MH mutations enhance ECCE compared with wild type; and 3) the increased Ca2+ entry might play a significant role in the pathophysiology of MH.

UR - http://www.scopus.com/inward/record.url?scp=38049134769&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=38049134769&partnerID=8YFLogxK

U2 - 10.1074/jbc.M701379200

DO - 10.1074/jbc.M701379200

M3 - Article

C2 - 17942409

AN - SCOPUS:38049134769

VL - 282

SP - 37471

EP - 37478

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 52

ER -