Alteration of intracellular Ca2+ transients in COS-7 cells transfected with the cDNA encoding skeletal-muscle ryanodine receptor carrying a mutation associated with malignant hyperthermia.
Malignant hyperthermia (MH), an inherited neuromuscular disease triggered by halogenated inhalational anaesthetics and skeletal-muscle relaxants, appears to be due to an alteration of intracellular Ca2+ homoeostasis. MH occurs in 1 out of 20,000 anaesthetized adults and is characterized by hypermetabolism, skeletal-muscle rigidity and elevation in body temperature, which is frequently fatal [MacLennan and Phillips (1992) Science 256, 789-794]. The defect responsible for the disease may lie within the mechanism controlling the release of Ca2+ from sarcoplasmic reticulum via the ryanodine-receptor (RYR) Ca2+ channel; in fact a point mutation in the RYR has been associated with MH in some human families, as well as in the MH-susceptible pig. To date, however, no direct evidence has been obtained demonstrating that the point mutation is both necessary and sufficient to cause functional alterations in RYR-mediated Ca2+ release. In the present report we show that the presence of the Arg-to-Cys point mutation in the recombinant RYR expressed in COS-7 transfected cells causes abnormal cytosolic Ca2+ transients in response to 4-chloro-m-cresol, an agent capable of eliciting in vitro contracture of MH-susceptible muscles.
Treves
S
S
Istituto di Patologia Generale, Università degli Studi di Ferrara, Italy.
Larini
F
F
Menegazzi
P
P
Steinberg
T H
TH
Koval
M
M
Vilsen
B
B
Andersen
J P
JP
Zorzato
F
F
D000595:Amino Acid Sequence; D001358:Avian Sarcoma Viruses / Q000235:genetics; D001483:Base Sequence; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D008305:Malignant Hyperthermia / Q000235:genetics*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics* / Q000502:physiology; D009132:Muscles / Q000737:chemistry; D009154:Mutation; D011401:Promoter Regions, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D019837:Ryanodine Receptor Calcium Release Channel; D014162:Transfection
D015220:Calcium Channels; D018076:DNA, Complementary; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium