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 the present paper we have defined putative functional domains of the ryanodine receptor Ca2+ channel. cDNA fragments of the skeletal muscle ryanodine receptor were fused in-frame with the Escherichia coli trpe protein and the resulting fusion proteins were evaluated for their ability to react with anti-(ryanodine receptor) antibodies, which are known to block Ca(2+)-dependent activation of the Ca(2+)-release channel. Anti-(ryanodine receptor) antibodies react with epitopes lying within a 245-amino-acid-long polypeptide which is located in a region (residues 4380-4625) encompassing most of myoplasmic loop 2, the predicted transmembrane segment M5 and part of the next lumenal loop (45 residues). Purification of the anti-(ryanodine receptor) antibodies by affinity chromatography led to the isolation of a population of antibodies which was capable of decreasing (by > 30%) the doxorubicin-induced Ca2+ release from isolated terminal cisternae. Polyclonal antibodies raised against a ryanodine receptor fusion encompassing part (198 out of 245 residues) of the immunopositive polypeptide decreased by 2-fold the first-order rate constant of Ca(2+)-induced 45Ca2+ efflux from isolated terminal cisternae. These results suggest strongly that the Ca(2+)-activating domain of the skeletal muscle Ca(2+)-release channel is close to, or associated with, myoplasmic loop 2.
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PMID:Identification of the domain recognized by anti-(ryanodine receptor) antibodies which affect Ca(2+)-induced Ca2+ release. 768 74

In earlier studies (Chen, S. R. W., Zhang, L., and MacLennan, D. H. (1992) J. Biol. Chem. 267, 23318-23326), an amino acid sequence, designated 13c2, lying between amino acid residues 4478 and 4512 in the skeletal muscle ryanodine receptor was shown, through the use of a polyclonal antibody, to be involved in Ca(2+)-induced Ca2+ release. In the present study, an immobilized synthetic peptide, PEPEPEPEPE, corresponding to part of the predicted high affinity Ca2+ binding site between residues 4489 and 4499, was used to purify specific antibodies from an anti-13c2 rabbit antiserum. The effect of this affinity-purified, anti-peptide (anti-13cp1) antibody on Ca2+ release channel function was then characterized using single channel recordings across planar lipid bilayers. The anti-peptide antibody inhibited Ca(2+)- or caffeine-activated channel activities without closing the channel but did not diminish ATP-activated channel activity. The addition of ATP reversed the inhibition of the Ca(2+)- or caffeine-activated channel by the antibody, and the antibody-bound, ATP-activated channel was further modulated by Mg2+, ryanodine, and ruthenium red. The major epitopes in the anti-13c2 antibody, previously shown to activate the Ca2+ release channel by increasing the Ca2+ sensitivity of the channel, did not lie in the PE repeat. These results suggest that the PE repeat sequence forms a site involved in the Ca2+ activation pathway.
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PMID:Antibodies as probes for Ca2+ activation sites in the Ca2+ release channel (ryanodine receptor) of rabbit skeletal muscle sarcoplasmic reticulum. 768 61

Calmodulin (CaM) is a regulator of the calcium release channel (ryanodine receptor) of the sarcoplasmic reticulum of skeletal and cardiac muscle. The locations where CaM binds on the surface of the skeletal muscle ryanodine receptor were determined by electron microscopy. Wheat germ CaM was labeled specifically at Cys-27 with a maleimide derivative of a 1.4-nm-diameter gold cluster, and the gold-cluster-labeled CaM was bound to the purified ryanodine receptor. The complexes were imaged in the frozen-hydrated state by cryoelectron microscopy with no stains or fixatives present. In the micrographs, gold clusters were frequently observed near the corners of the square-shaped images of the ryanodine receptors. In some images, all four corners of the receptor were occupied by gold clusters. Image averaging allowed the site of CaM binding to be determined in two dimensions with an estimated precision of 4 nm. No changes were apparent in the quaternary structure of the ryanodine receptor upon binding CaM to the resolution attained, about 3 nm. Side views of the ryanodine receptor, in which the receptor is oriented approximately perpendicular to the much more frequent fourfold symmetric views, were occasionally observed, and showed that the CaM binding site is most likely on the surface of the receptor that faces the cytoplasm. We conclude that the CaM binding site is at least 10 nm from the transmembrane channel of the receptor and, consequently, that long-range conformational changes are involved in the modulation of the calcium channel activity of the receptor by CaM.
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PMID:Localization of calmodulin binding sites on the ryanodine receptor from skeletal muscle by electron microscopy. 769 69

The membrane topology of the skeletal muscle ryanodine receptor (RyR1) was investigated using site-directed antibodies directed against amino acid sequences 2804-2930, 4581-4640, 4860-4886, and 4941-5037. Ab(2804-2930) bound with identical affinity to either closed or permeabilized sarcoplasmic reticulum vesicles, confirming the cytoplasmic location of this segment. Ab(4581-4640) did not bind to closed vesicles but bound well to permeabilized vesicles, supporting a lumenal location for this segment. Ab(4860-4886) did not bind to closed vesicles but exhibited weak binding to the permeabilized vesicles, suggesting that a portion of the epitope may be exposed on the lumenal surface. The C-terminal antibody (Ab(4941-5037)) bound weakly to closed vesicles, and binding was not significantly enhanced by permeabilizing vesicles with low concentrations of non-denaturing detergent. However, the C-terminal antibodies bound efficiently to vesicles which were transiently incubated at alkaline pH or subjected to trypsinolysis, conditions where few of the vesicles were permeabilized. These results support a model for the membrane topology of the ryanodine receptor as proposed by Takeshima et al. (Takeshima, H., Nishimura, S., Matsumoto, T., Ishida, H., Kangawa, K., Minamino, N., Matsuo, H., Ueda, M., Hanaoka, M., Hirose, T., and Numa, S. (1989) Nature 339, 439-445). The results also suggest that the native conformation of the C terminus is inaccessible to antibodies.
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PMID:Lumenal sites and C terminus accessibility of the skeletal muscle calcium release channel (ryanodine receptor). 774 71

We have tested the periodate-oxidized ATP analogue 2',3'-dialdehyde adenosine triphosphate (oATP) as a ligand for the skeletal muscle ryanodine receptor/Ca(2+)-release channel. Ca2+ efflux from passively loaded heavy sarcoplasmic reticulum vesicles of skeletal muscle is biphasic. oATP stimulates the initial phase of Ca2+ release in a concentration-dependent manner (EC50 160 microM), and the efflux proceeds with a half-time in the range 100-200 ms. This oATP-modulated initial rapid Ca2+ release was specifically inhibited by millimolar concentrations of Mg2+ and micromolar concentrations of Ruthenium Red, indicating that the effect of oATP was mediated via the ryanodine receptor. The purified Ca(2+)-release channel was incorporated into planar lipid bilayers, and single-channel recordings were carried out to verify a direct interaction of oATP with the ryanodine receptor. Addition of oATP to the cytoplasmic side activated the channel with an EC50 of 76 microM, which is roughly 30-fold higher than the apparent affinity of ATP. The oATP-induced increase in the open probability of the ryanodine receptor displays a steep concentration-response curve with a Hill coefficient of approximately 2, which suggests a co-operativity of the ATP binding sites in the tetrameric protein. oATP binds to the ryanodine receptor in a quasi-irreversible manner via Schiff base formation between the aldehyde groups of oATP and amino groups in the nucleotide binding pocket. This allows for the covalent specific incorporation of [alpha-32P]oATP by borhydride reduction. A typical adenine nucleotide binding site cannot be identified in the primary sequence of the ryanodine receptor. Our results demonstrate that oATP can be used to probe the structure and function of the nucleotide binding pocket of the ryanodine receptor and presumably of other ATP-regulated ion channels.
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PMID:Activation and labelling of the purified skeletal muscle ryanodine receptor by an oxidized ATP analogue. 775 53

The fluorogenic maleimide 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin (CPM) has been shown to selectively form Michael adducts with hyperreactive sulfhydryls on the skeletal sarcoplasmic reticulum (SR) ryanodine receptor (RyR1) and triadin which are essential for normal Ca2+ channel function (Liu, G., Abramson, J.J., Zable, A.C., and Pessah, I.N. (1994) Mol. Pharmacol. 45, 189-200). The present report demonstrates a functionally important interaction between RyR1 and triadin which involves, in part, redox cycling of hyperreactive sulfhydryls in response to channel activation and inactivation. Nanomolar CPM is shown to selectively label RyR1 and triadin only in the presence of Ca2+ channel inhibitors (Mg2+, neomycin, ruthenium red, or anti-triadin antibody). Treatment of SR with channel activators (micromolar Ca2+, nanomolar ryanodine, or millimolar caffeine), 1) slows CPM labeling kinetics > 10-fold, 2) negates CPM labeling of channel-associated sulfhydryls, and 3) stabilizes a high molecular weight complex (HMWC) which appears on nonreducing SDS-polyacrylamide gel electrophoresis gels. The HMWC is positively identified as RyR1 and triadin by Western blot and immunoprecipitation analyses. High-affinity [3H]ryanodine-binding sites are immunoprecipitated by either anti-RyR1 or anti-triadin antibody dose dependently. 1,4-Naphthoquinone (< or = 40 pmol/micrograms protein) selectively oxidizes hyperreactive sulfhydryls on RyR1 and triadin, induces Ca2+ efflux from SR, and stabilizes the HMWC. The HMWC is reduced by beta-mercaptoethanol or dithiothreitol into its component RyR1 and triadin promoters. The results provide direct evidence for the existence of a functionally important complex between RyR1 and triadin whose stability is determined by the redox state of hyperreactive sulfhydryl moieties which are allosterically regulated by physiological and pharmacological channel ligands. The present results suggest a possible molecular mechanism by which localized transient changes in the redox state within the RyR1-triadin complex can signal information across the SR membrane.
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PMID:Molecular interaction between ryanodine receptor and glycoprotein triadin involves redox cycling of functionally important hyperreactive sulfhydryls. 780 31

The ryanodine receptor is a channel for Ca2+ release from intracellular stores. By PCR analysis, we identified two alternatively spliced regions in mRNA of the mouse skeletal muscle ryanodine receptor (sRyR). The splice variants were characterized by the presence or absence of 15 bp (ASI) and 18 bp (ASII) exons. The exclusion of these exons results in the absence of the regions corresponding to Ala3481-Gln3485 and Val3865-Asn3870, respectively, of rabbit sRyR; these amino acid sequences exist in the modulatory region, where sites for phosphorylation and binding of Ca2+, calmodulin and ATP are postulated to be. We also detected sRyR in brain and heart as well as in skeletal muscle, and the splicing patterns were found to be tissue-specific. Only the ASII-lacking isoform was detected in heart, whereas in other tissues the ASII-containing isoform was predominant. The splicing patterns were also found to change during development. In skeletal muscle, the ASI-containing isoform increased gradually from embryo to adult. The ASII-lacking isoform abruptly increased upon birth, but the ASII-containing isoform increased steadily afterwards. In cerebrum, the ratio of the ASII-containing isoform to the ASII-lacking one increased abruptly during embryonic days 14 and 18. These findings suggest that the alternative splicing of ASI and ASII, by affecting the modulatory region, generates functionally different sRyR isoforms in a tissue-specific and developmentally regulated manner.
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PMID:Tissue-specific and developmentally regulated alternative splicing in mouse skeletal muscle ryanodine receptor mRNA. 783 48

Malignant hyperthermia (MH) is a potentially fatal autosomal dominant disorder of skeletal muscle and is triggered in susceptible people by all commonly used inhalational anaesthetics and depolarizing muscle relaxants. To date, six mutations in the skeletal muscle ryanodine receptor gene (RYR1) have been identified in malignant hyperthermia susceptible (MHS) and central core disease (CCD) cases. Using SSCP analysis, we have screened the RYR1 gene in affected individuals for novel MHS mutations and have identified a G to A transition mutation which results in the replacement of a conserved Gly at position 2433 with an Arg. The Gly2433Arg mutation was present in four of 104 unrelated MHS individuals investigated and was not detected in a normal population sample. This mutation is adjacent to the previously identified Arg2434His mutation reported in a CCD/MH family and indicates that there may be a second region in the RYR1 gene where MHS/CCD mutations cluster.
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PMID:Detection of a novel RYR1 mutation in four malignant hyperthermia pedigrees. 784 12

Ryanodine receptors (RyRs) are intracellular calcium release channels that participate in controlling cytosolic calcium levels. At variance with the probably ubiquitous inositol 1,4,5-trisphosphate-operated calcium channels (1,4,5-trisphosphate receptors), RyRs have been mainly regarded as the calcium release channels controlling skeletal and cardiac muscle contraction. Increasing evidence has recently suggested that RyRs may be more widely expressed, but this has never been extensively examined. Therefore, we cloned three cDNAs corresponding to murine RyR homologues to carry a comprehensive analysis of their expression in murine tissues. Here, we report that the three genes are expressed in almost all tissues analyzed, where tissue-specific patterns of expression were observed. In the uterus and vas deferens, expression of RyR3 was localized to the smooth muscle component of these organs. In the testis, expression of RyR1 and RyR3 was detected in germ cells. RyR mRNAs were also detected in in vitro-cultured cell lines. RyR1, RyR2, and RyR3 mRNA were detected in the cerebrum and in the cerebellum. In situ analysis revealed a cell type-specific pattern of expression in the different regions of the central nervous system. The differential expression of the three ryanodine receptor genes in the central nervous system was also confirmed using specific antibodies against the respective proteins. This widespread pattern of expression suggests that RyRs may participate in the regulation of intracellular calcium homeostasis in a range of cells wider than previously recognized.
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PMID:The ryanodine receptor/calcium channel genes are widely and differentially expressed in murine brain and peripheral tissues. 787 12

Single strand conformational polymorphism analysis was used to screen exons 43 and 44 in the skeletal muscle ryanodine receptor gene from 17 positively diagnosed members of families in which chromosome 19-linked malignant hyperthermia (MH) was segregating. A polymorphism in two unrelated individuals was found to result from the substitution of A for G7297, leading to the substitution of Arg for Gly2433. This mutation is adjacent to a mutation (Arg2434 to His) previously linked to MH and central core disease (Y. Zhang et al., Nature Genet. 1993, 5, 46-50). Subsequent screening showed the presence of the mutation in four of 106 MH families tested and its absence from about 1000 other chromosomes. The mutation was present in all six individuals in four families who had had an MH reaction, in two obligate carriers and in 10 individuals diagnosed as MH susceptible by the caffeine/halothane contracture test (CHCT). The mutation was present in an individual with a normal response to the CHCT and was absent in three individuals with a positive CHCT response. These discrepancies would be consistent with inaccuracies in the CHCT and/or with segregation of a second MH allele within two of the four affected families.
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PMID:The substitution of Arg for Gly2433 in the human skeletal muscle ryanodine receptor is associated with malignant hyperthermia. 788 17


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