Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P21817 (RyR1)
 1,154 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this study, the binding of [3H]ryanodine to liver microsomal subfractions was investigated. The specific binding of [3H]ryanodine, as determined both by vacuum filtration and by ultracentrifugation, is to a single class of high-affinity binding sites with a Kd of 10 +/- 2.5 nM and density of 500 +/- 100 and 1200 +/- 200 fmol/mg of protein by the filtration and centrifugation methods respectively. [3H]Ryanodine binding reached equilibrium in about 1 min and 2 min at 36 degrees C and 24 degrees C respectively, and the half-time of dissociation at 37 degrees C was approx. 15 s. The binding of [3H]ryanodine is Ca(2+)-independent: it is slightly stimulated by NaCl, Mg2+, ATP and InsP3 but strongly inhibited by caffeine, diltiazem and sodium dantrolene. Thus the binding of ryanodine to endoplasmic reticulum membranes shares some of the characteristics of its binding to the sarcoplasmic reticulum but also differs from it in several important properties, such as its Ca(2+)-independence, its rapid association and dissociation, and its inhibition by caffeine. The structural similarities between the skeletal muscle and liver binding sites were further explored by employing in vitro DNA amplification techniques, using the known sequence of the skeletal muscle receptor as reference point. The data obtained with this method indicate that the liver does not process mRNA for the skeletal muscle ryanodine receptor.
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PMID:Characterization of high-affinity ryanodine-binding sites of rat liver endoplasmic reticulum. Differences between liver and skeletal muscle. 203 82

Contraction of skeletal muscle is triggered by the release of Ca2+ from the sarcoplasmic reticulum (SR) after depolarization of transverse tubules. The ryanodine receptor exists as a 'foot' protein in the junctional gap between the sarcoplasmic reticulum and the transverse tubule in skeletal muscle, and is proposed to function as a calcium-release channel during excitation-contraction (E-C) coupling. Previous complementary DNA-cloning studies have defined three distinct subtypes of the ryanodine receptor in mammalian tissues, namely skeletal muscle, cardiac and brain types. We report here mice with a targeted mutation in the skeletal muscle ryanodine receptor gene. Mice homozygous for the mutation die perinatally with gross abnormalities of the skeletal muscle. The contractile response to electrical stimulation under physiological conditions is totally abolished in the mutant muscle, although ryanodine receptors other than the skeletal-muscle type seem to exist because the response to caffeine is retained. Our results show that the skeletal muscle ryanodine receptor is essential for both muscular maturation and E-C coupling, and also imply that the function of the skeletal muscle ryanodine receptor during E-C coupling cannot be substituted by other subtypes of the receptor.
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PMID:Excitation-contraction uncoupling and muscular degeneration in mice lacking functional skeletal muscle ryanodine-receptor gene. 751 81

A total of 392 pigs of European Landrace and Pietrain origin segregating for malignant hyperthermia (MH) were genotyped using a polymerase chain reaction (PCR)/restriction endonuclease test for the C-T mutation at nucleotide (nt) 1843 in the skeletal muscle ryanodine receptor (RYR1) gene, earlier identified as the causal mutation for MH. All pigs had been halothane tested and genotyped at linked polymorphic marker loci. There was complete correlation between MH status of the 392 animals, as diagnosed by a combination of the halothane challenge test with S, GPI, H, A1BG, PGD haplotyping, and the DNA-based test. DNA-based detection of the MH status in 238 MH-susceptible heterozygous (N/n) and homozygous (n/n) pigs was shown to be accurate, eliminating the 2% diagnostic error that is associated with the halothane challenge test. The mutation was also associated with an allele of a polymorphic microsatellite (ETH5 001) at the RYR1 locus.
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PMID:Co-segregation of the malignant hyperthermia and the Arg615-Cys615 mutation in the skeletal muscle calcium release channel protein in five European Landrace and Pietrain pig breeds. 794 85

Excitation-contraction coupling in skeletal muscle is mediated by two calcium channels located in the membranes of the transverse tubule and the sarcoplasmic reticulum. Calcium is released from the terminal cisternae of the sarcoplasmic reticulum via the ryanodine receptor. Abnormal increases in myoplasmic free calcium caused by a defect in the ryanodine receptor have been reported in malignant hyperthermia. Malignant hyperthermia is a life-threatening pharmacogenetic disorder in a variety of species and is triggered by volatile anesthetics and depolarizing muscle relaxants. To study the genomic organization of the porcine skeletal muscle ryanodine receptor gene, we have isolated six genomic fragments spanning approximately 80 kb of chromosomal DNA. In this report, we describe the genomic organization of a 15.5-kb genomic fragment comprising 18 exons coding for region 4624 to 7929 of the porcine skeletal muscle ryanodine receptor gene.
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PMID:Genomic organization of the porcine skeletal muscle ryanodine receptor (RYR1) gene coding region 4624 to 7929. 828 38

Pietrain swine homozygous for the hal gene (n) associated with porcine stress syndrome (PSS) and a Pietrain-derivative breed, Near Pietrain (NP), with a frequency of .31 for n, were mated to produce reciprocal F1, F2, and purebred NP litters. The halothane challenge test was performed on all 40 parents and 240 progeny to predict their hal genotype and PSS susceptibility. The DNA-based assay for a C to T mutation at base pair 1,843 of the skeletal muscle ryanodine receptor (ryr1) cDNA, which is very highly correlated with PSS, was also determined for these animals. The predicted hal genotypes observed in the progeny differed significantly from the expected Mendelian ratios, and the halothane challenge test consistently overestimated the n/n hal genotype. However, the ryr1 genotypes observed in the progeny did not differ significantly from the expected Mendelian ratios, and this DNA-based assay apparently misidentified only one of the 40 parents. The results of this study indicate that the assay for the ryr1 mutation more accurately predicts both the homozygous and heterozygous forms of the PSS gene than does the halothane challenge test.
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PMID:Relative accuracy of the halothane challenge test and a molecular genetic test in detecting the gene for porcine stress syndrome. 839 44

Vitamin A serves as a prohormone from which three classes of active metabolites are derived: the aldehydes, the carboxylic acids, and the retro-retinoids. Although these three classes are united under the rubric of signal transduction, they act by different molecular mechanisms: the 11-cis-retinaldehydes combine with opsin to form the universal visual pigments and the retinoic acids form ligands for transcription factors, whereas the retro-retinoids, as shown here, intersect with signal transduction at a cytoplasmic or membrane site. The retro-retinoid, anhydroretinol (AR), has long been known to act as a growth inhibitor in lymphocytes, whereas 14-hydroxy-4,14-retro-retinol (14-HRR) is required for normal lymphocyte proliferation. A mutually reversible relationship exists between these two retro-retinoids as one can reverse the effects of the other when given in pharmacological doses. The common explanation for reversible inhibition is competition for a shared receptor. We now provide evidence that when AR is given to T cells unmitigated by 14-HRR, rapid cell death can occur. The circumstances are closely related to nonclassical forms of apoptosis: within 2 h of AR administration the T cells undergo widespread morphological changes, notably surface blebbing and ballooning and, inevitably, bursting. In contrast, nuclear changes are comparatively mild, as indicated by absence of chromatin condensation and overt DNA cleavage to discrete nucleosomal fragments, although DNA nicks are readily discernible by terminal deoxynucleotidyl transferase assay. What further distinguishes the AR-induced form of apoptosis from classical ones is a lack of requirements of messenger RNA and protein synthesis, suggesting that the events leading to cell death are primarily initiated and play themselves out in the cytoplasm. This view is further reinforced by the finding that herbimycin A can prevent the onset of programmed cell death. The importance of our findings is that they strongly suggest a second messenger role for vitamin A metabolites in the cytoplasmic realm that has not been seen previously. These findings are entirely compatible with a general notion that in a cell requiring multiple coordinated signals for survival, the provision of an unbalanced signal can initiate programmed cell death. Collectively, our data also challenge the paradigm that retinoids (outside vision) solely mediate their function via the steroid/ retinoic acid receptor family of nuclear transcription factors. Instead, a mode of action in the cytoplasmic realm akin to one attributed to other small lipophilic second messenger molecules, such as diacyl glycerol or ceramide, may apply to retro-retinoids.
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PMID:Retro-retinoids in regulated cell growth and death. 876 Aug 8

The skeletal muscle ryanodine receptor (RYR1) belongs to a family of calcium release channels that are expressed in different tissues. The RYR1 gene is one of the largest genes characterized, so far, containing a 15253 nucleotide ORF in swine. To study the genomic organization of the porcine skeletal muscle ryanodine receptor gene we have isolated seven genomic fragments spanning 72.7 kb of chromosomal DNA of chromosome 6q12. This region harbours exons 1 to 71 coding for 3538 amino acids (69.6%) of the ryanodine receptor 1.
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PMID:The porcine skeletal muscle ryanodine receptor gene structure coding region 1 to 10614 harbouring 71 exons. 893 69

Malignant hyperthermia (MH) is a potentially fatal, inherited pharmacogenetic disorder characterised by a dysfunction of the intracellular calcium regulation. Linkage to DNA markers from the chromosome 19q12-13.2 region and the MHS-phenotype (MH susceptible) has been shown in about 50% of families with a history of MH. The ryanodine receptor gene encoding the human skeletal muscle ryanodine receptor has been localised to the chromosome 19q13.1-13.2 region. The ryanodine receptor, which is an intracellular calcium release channel, has been proposed to be one of the candidate structures for the MH defect. At present, eight different single point mutations have been identified in the human skeletal muscle ryanodine receptor gene in families with disposition to MH. The incidence of the various mutations has been reported as 2-10% each. A combination of different mutations within one pedigree has not been demonstrated. A few years ago, linkage of the MHS-phenotype to DNA markers from the chromosome 17q11.2-24 region was published by an American group. However, this observation has not been confirmed in any of the several European families susceptible to MH. Genes encoding for subunits of the dihydropyridine receptor and the sodium channel of the human skeletal muscle have been found to be located in the chromosome 17q11.2-24 region which, in fact, could be additional candidates for the MH defect. The dihydropyridine receptor is linked to the ryanodine receptor and involved in the calcium regulation of skeletal muscle. Very recent studies have shown linkage to DNA markers from chromosome 7q- and chromosome 3q13.1 regions and the MHS phenotype in two distinct families with history of MH. However, the relevance of this observation is so far unknown. At present, unambiguous preoperative screening of MH disposition based on molecular genetic characteristics is not available because of the enormous heterogeneity of the human MH syndrome. Thus, the halothane-caffeine in-vitro contracture test according to the standard protocol of the "European MH Group" must be performed in order to discover MH susceptibility.
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PMID:[What significance to genotype changes have in diagnosis of malignant hyperthermia?]. 896 26

A single base change in the RYR1 gene encoding the skeletal muscle ryanodine receptor (calcium-sensitive calcium-release channel of the sarcoplasmic reticulum), resulting in the substitution of G1021 by A, has been proposed to underlie malignant-hyperthermia (MH) susceptibility in as many as 10% of cases in the European population. As part of our mutation-screening program in MH-susceptible (MHS) individuals, we have investigated this substitution in individuals from 151 unrelated British MHS families and have detected G1021A heterozygotes in 7 families. This mutation was not found in 156 unrelated MH-negative (MHN) individuals. We also examined eight families with central core disease (CCD): the mutation did not occur in any family members of any disease status (affected or unaffected for CCD, MHS, or MHN). In one large family, the G1021A mutation was found but did not show complete cosegregation with MH susceptibility: it occurred in only 7/12 MHS individuals in the kinship, and susceptibility was inherited from parents who were G1021 homozygotes, as well as from parents who were heterozygotes. On the basis of these findings, it is clearly unreliable at present to offer presymptomatic DNA testing for MH status, even in families in which a mutation has been detected.
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PMID:The G1021A substitution in the RYR1 gene does not cosegregate with malignant hyperthermia susceptibility in a British pedigree. 910 29

Malignant hyperthermia (MH) is a potentially fatal autosomal dominant disorder of skeletal muscle and is triggered in susceptible people by all commonly used inhalation anaesthetics and depolarizing neuromuscular blocking agents. To date, eight mutations in the skeletal muscle ryanodine receptor gene (RYR1) have been identified in malignant hyperthermia susceptible (MHS) and central core disease (CCD) cases. We have screened the RYR1 gene in affected individuals for novel MHS mutations by single stranded conformational polymorphism (SSCP) analysis and have identified a G to T transition mutation which results in the replacement of a conserved arginine (Arg) at position 614 with a leucine (Leu). The Arg614Leu mutation was present in three unrelated MHS individuals of 151 investigated. The mutation was not detected in 148 normal chromosomes and segregated precisely with MHS in family members from one of the probands where DNA was available for analysis. This mutation occurs at the same position as the previously identified Arg to Cys mutation reported in all cases of porcine MH and in approximately 5% of human MH. A comparison of the phenotypes of the Arg614Leu and Arg614Cys probands is presented.
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PMID:Detection of a novel mutation at amino acid position 614 in the ryanodine receptor in malignant hyperthermia. 938 51


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