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)

A high affinity [3H]ryanodine receptor has been solubilized from rabbit brain membranes and biochemically characterized. [3H]Ryanodine binding to rabbit brain membranes is specific and saturable, with a Kd of 1.3 nM. [3H]Ryanodine binding is enriched in membranes from the hippocampus but is significantly lower in membranes from the brain stem and spinal cord. Approximately 60% of [3H]ryanodine-labeled receptor is solubilized from brain membranes using 2.5% CHAPS and 10 mg/ml phosphatidylcholine containing 1 M NaCl. The solubilized brain [3H]ryanodine receptor sediments through sucrose gradients like the skeletal receptor as a large (approximately 30 S) complex. Solubilized receptor is specifically immunoprecipitated by sheep polyclonal antibodies against purified skeletal muscle ryanodine receptor coupled to protein A-Sepharose. [3H]Ryanodine-labeled receptor binds to heparin-agarose, and a protein of approximately 400,000 Da, which is cross-reactive with two polyclonal antibodies raised against the skeletal muscle ryanodine receptor, elutes from the column and is enriched in peak [3H]ryanodine binding fractions. These results suggest that the approximately 400,000-Da protein is the brain form of the high affinity ryanodine receptor and that it shares several properties with the skeletal ryanodine receptor including a large oligomeric structure composed of approximately 400,000-Da subunits.
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PMID:Solubilization and biochemical characterization of the high affinity [3H]ryanodine receptor from rabbit brain membranes. 221 13

Single-channel recordings have indicated that ryanodine receptor (RyR1) mutation Arg615Cys of porcine malignant hyperthermia-susceptible (MHS) muscle is not directly associated with the enhanced caffeine sensitivity of MH(S) muscle [1]. In the present study, the effect of a novel activator of RyR1, 4-chlorom-cresol (4-CmC), was investigated on high-affinity [3H]ryanodine binding to porcine skeletal sarcoplasmic reticulum. The 4-CmC affinity of [3H]ryanodine binding to MHS vesicles was 2-fold higher compared to that in normal tissue. This enhanced affinity was confirmed when the effect of 4-CmC on [3H]ryanodine binding to the isolated CHAPS-solubilized MHS RyR1 was investigated. 4-CmC is, therefore, suggested to be a potent tool to distinguish between Ca2+ release from MHS and normal muscle.
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PMID:4-Chloro-m-cresol: a specific tool to distinguish between malignant hyperthermia-susceptible and normal muscle. 867 99

A rapid assay for high affinity [3H]ryanodine binding to 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS)-solubilized recombinant or native Ca2+ release channel proteins (ryanodine receptor, RyR) was devised. The key to preservation of high affinity [3H]ryanodine binding sites in the presence of increasing concentrations of CHAPS was the addition of phosphatidylcholine. This assay was used to characterize the equilibrium and kinetic properties of [3H]ryanodine binding to recombinant skeletal (RyR1) and cardiac (RyR2) Ca2+ release channels and the effects on binding of physiological modulators including ATP, Ca2+, and Mg2+. Both RyR1 and RyR2 had a single high affinity ryanodine binding site and low affinity sites, but [3H]ryanodine binding to recombinant RyR2 was not sensitive to ATP activation or Ca2+ inactivation and was less sensitive to Mg2+ inhibition. The [3H]ryanodine binding assay was used to estimate the expression level of recombinant RyR2 and RyR1, and to show that RyR2 can be expressed at very high levels in HEK-293 cells. Analysis of the properties of recombinant RyR2 and RyR1 by measurement of intracellular Fura-2 fluorescence revealed that the different properties of RyR2 and RyR1 are retained in the recombinant expressed proteins.
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PMID:Characterization of recombinant rabbit cardiac and skeletal muscle Ca2+ release channels (ryanodine receptors) with a novel [3H]ryanodine binding assay. 983 97

We showed that frog alpha-ryanodine receptor (alpha-RyR) had a lower gain of Ca(2+)-induced Ca(2+) release (CICR) activity than beta-RyR in sarcoplasmic reticulum (SR) vesicles, indicating selective "stabilization" of the former isoform (Murayama T and Ogawa Y. J Biol Chem 276: 2953-2960, 2001). To know whether this is also the case with mammalian RyR1, we determined [(3)H]ryanodine binding of RyR1 and RyR3 in bovine diaphragm SR vesicles. The value of [(3)H]ryanodine binding (B) was normalized by the number of maximal binding sites (B(max)), whereby the specific activity of each isoform was expressed. This B/B(max) expression demonstrated that ryanodine binding of individual channels for RyR1 was <15% that for RyR3. Responses to Ca(2+), Mg(2+), adenine nucleotides, and caffeine were not substantially different between in situ and purified isoforms. These results suggest that the gain of CICR activity of RyR1 is markedly lower than that of RyR3 in mammalian skeletal muscle, indicating selective stabilization of RyR1 as is true of frog alpha-RyR. The stabilization was partly eliminated by FK506 and partly by solubilization of the vesicles with CHAPS, each of which was additive to the other. In contrast, high salt, which greatly enhances [(3)H]ryanodine binding, caused only a minor effect on the stabilization of RyR1. None of the T-tubule components, coexisting RyR3, or calmodulin was the cause. The CHAPS-sensitive intra- and intermolecular interactions that are common between mammalian and frog skeletal muscles and the isoform-specific inhibition by FKBP12, which is characteristic of mammals, are likely to be the underlying mechanisms.
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PMID:RyR1 exhibits lower gain of CICR activity than RyR3 in the SR: evidence for selective stabilization of RyR1 channel. 1498 35

Ryanodine receptor (RyR) type 1 (RyR1) exhibits a markedly lower gain of Ca(2+)-induced Ca(2+) release (CICR) activity than RyR type 3 (RyR3) in the sarcoplasmic reticulum (SR) of mammalian skeletal muscle (selective stabilization of the RyR1 channel), and this reduction in the gain is largely eliminated using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS). We have investigated whether the hypothesized interdomain interactions within RyR1 are involved in the selective stabilization of the channel using [(3)H]ryanodine binding, single-channel recordings, and Ca(2+) release from the SR vesicles. Like CHAPS, domain peptide 4 (DP4, a synthetic peptide corresponding to the Leu(2442)-Pro(2477) region of RyR1), which seems to destabilize the interdomain interactions, markedly stimulated RyR1 but not RyR3. Their activating effects were saturable and nonadditive. Dantrolene, a potent inhibitor of RyR1 used to treat malignant hyperthermia, reversed the effects of DP4 or CHAPS in an identical manner. These findings indicate that RyR1 is activated by DP4 and CHAPS through a common mechanism that is probably mediated by the interdomain interactions. DP4 greatly increased [(3)H]ryanodine binding to RyR1 with only minor alterations in the sensitivity to endogenous CICR modulators (Ca(2+), Mg(2+), and adenine nucleotide). However, DP4 sensitized RyR1 four- to six-fold to caffeine in the caffeine-induced Ca(2+) release. Thus the gain of CICR activity critically determines the magnitude and threshold of Ca(2+) release by drugs such as caffeine. These findings suggest that the low CICR gain of RyR1 is important in normal Ca(2+) handling in skeletal muscle and that perturbation of this state may result in muscle diseases such as malignant hyperthermia.
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PMID:Postulated role of interdomain interactions within the type 1 ryanodine receptor in the low gain of Ca2+-induced Ca2+ release activity of mammalian skeletal muscle sarcoplasmic reticulum. 1567 76

Two isoforms of ryanodine receptors are expressed in skeletal muscles, RyR1 and RyR3. We investigated the relative level of expression of RyRs in developing murine skeletal muscles using [3H]ryanodine binding and immunoprecipitation experiments. In the diaphragm RyR3 accounted for 11% of total RyRs in 5-day-old mice and for 3% of total RyRs in 60-day-old mice. In hindlimb muscles, RyR3 accounted for 3% and 1% of total RyRs in 5-day-old and adult mice, respectively. The activity of RyR1 channels in native microsomal vesicles from murine muscles was found to be as low as 35% of that measured after CHAPS exposure, while no inhibition was observed for RyR3. CHAPS sensitivity of recombinant RyR1 and RyR3 expressed in HEK293 cells was also investigated. The activity of recombinant RyR1 but not RyR3 channels was found to be inhibited in native conditions, suggesting that this property may not be dependent on a muscle environment.
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PMID:Expression and functional activity of ryanodine receptors (RyRs) during skeletal muscle development. 1711 45