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

A polypeptide of high molecular mass has been detected in mammalian brain by a monoclonal antibody, 5C3, raised against skeletal muscle ryanodine receptor. 5C3 does not crossreact with the cardiac ryanodine receptor, the isoform which is believed to be located in many regions of the brain. Endogenous proteases in brain formed a prominent immunogenic fragment of 116 kDa whereas five immunostaining polypeptides greater than 200 kDa were observed in skeletal muscle. Mild trypsin digestion of brain microsomes resulted in fragments of approximately 400 and approximately 280 kDa, of similar mass to two peptides formed from the skeletal muscle ryanodine receptor. However a peptide of 28 kDa, resistant to trypsin, was observed in muscle but not in brain. The brain polypeptide recognised by 5C3 is therefore not identical to the skeletal muscle ryanodine receptor.
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PMID:Monoclonal antibody to skeletal muscle ryanodine receptor detects a polypeptide in rat brain: comparison of immunogenic fragments after limited proteolysis. 801 88

The photoaffinity analog of ATP, 3'-O-(4-benzoyl)benzoyl-adenosine 5'-triphosphate (Bz2ATP) was used to covalently label and to identify the ATP binding site of the skeletal muscle ryanodine receptor. Like ATP, Bz2ATP stimulates up to fivefold the binding of ryanodine to its receptor. Photoactivation by ultraviolet light of the benzophenone group in the [alpha-32P]Bz2ATP results in covalent binding of [alpha-32P]Bz2ATP to the 450-kDa polypeptide, the ryanodine receptor's subunit. An apparent molar stiochiometry of Bz2ATP to the tetrameric ryanodine receptor complex of 1.146 +/- 0.087 (n = 2) was estimated. The covalent binding of [alpha-32P]Bz2ATP was inhibited by ATP and analogous compounds in the order: ATP = AdoPP[CH2]P = ADP = Ado = cAMP > AMP > ITP = GTP. Similar specificity was obtained for the stimulation of ryanodine binding by these nucleotides. ATP increased the ryanodine binding affinity by about sixfold. The polycationic dye ruthenium red, known as an inhibitor of Ca2+ release and ryanodine binding, inhibited the labeling of the ryanodine receptor by [alpha-32P]Bz2ATP. Tryptic digestion of the ryanodine receptor revealed a [alpha-32P]Bz2ATP-labeled 76-kDa tryptic fragment. Digestion of either the [alpha-32P]Bz2ATP-labeled 450-kDa or the 76-kDa polypeptides with S. aureus resulted in the appearance of four labeled fragments of 39, 33, 27 and 13 kDa, where the 39-kDa fragment is the precursor of the 27-kDa and 13-kDa fragments. The results suggest that the regulation of Ca2+ release by ATP involves an ATP binding site(s) located on the 27-kDa and 13-kDa fragments of the ryanodine receptor protein.
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PMID:Characterization and photoaffinity labeling of the ATP binding site of the ryanodine receptor from skeletal muscle. 838 21

A fusion protein encompassing Gly341 of the skeletal muscle ryanodine receptor was used to raise monoclonal antibodies; epitope mapping demonstrates that monoclonal antibody 419 (mAb419) reacts with a sequence a few residues upstream from Gly341. The mAb419 was then used to probe ryanodine receptor (RYR) functions. Our results show that upon incubation of triads vesicles with mAb419 the Ca2+-induced Ca2+ release rate at pCa 8 was increased. Equilibrium evaluation of [3H]ryanodine binding at different [Ca2+] indicates that mAb419 shifted the half-maximal [Ca2+] for stimulation of ryanodine binding to lower value (0.1 versus 1.2 microM). Such functional effects may be due to a direct action of the Ab on the Ca2+ binding domain of the RYR or to the perturbation by the Ab of the intramolecular interaction between the immunopositive region and regulatory domain of the RYR. The latter hypothesis was tested directly using the optical biosensor BIAcore (Pharmacia Biotech Inc.): we show that the immunopositive RYR polypeptide is able to interact with the native RYR complex. Ligand overlays with immunopositive digoxigenin-RYR fusion protein indicate that such an interaction might occur with a calmodulin binding domain (defined by residues 3010-3225) and with a polypeptide defined by residues 799-1172. In conclusion our results suggest that the stimulation by the mAb419 of the RYR channel activity is due to the perturbation of an intramolecular interaction between the immunopositive polypeptide and a Ca2+ regulatory site probably corresponding to a calmodulin binding domain.
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PMID:Role of malignant hyperthermia domain in the regulation of Ca2+ release channel (ryanodine receptor) of skeletal muscle sarcoplasmic reticulum. 879 51

We investigated type 3 isoform (RyR3) of ryanodine receptor in rabbit skeletal muscles using an antibody specific for RyR3. By Western blot analysis and by immunoprecipitation, a single polypeptide for RyR3 was detected in sarcoplasmic reticulum vesicles from rabbit diaphragm but not in those from back muscle. The molecular mass was slightly smaller than that of RyR1, the major isoform in skeletal muscles. Each of RyR1 and RyR3 formed a homotetramer in rabbit diaphragm. RyR3 had a single class of [3H]ryanodine binding sites of high affinity (KD = 1.6 nM). From the Bmax of the binding, the content of RyR3 was estimated to be only 0.6% of RyR1 in rabbit diaphragm. -3H-Ryanodine binding to RyR3 was biphasically dependent on Ca2+, as is true of RyR1, and was stimulated further by adenine nucleotide, caffeine, or high salt concentration. Procaine and ruthenium red inhibited the binding. RyR3 was more resistant to Mg2+ inhibition than RyR1. Interestingly, RyR3 showed about a 7-fold lower Ca2+ sensitivity for activation than RyR1. Comparison with the counterparts in bullfrog skeletal muscles indicates that the Ca2+ sensitivities of RyR3 homologs are similar to each other, whereas those of RyR1 homologs are species-specific.
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PMID:Characterization of type 3 ryanodine receptor (RyR3) of sarcoplasmic reticulum from rabbit skeletal muscles. 929 56

Ryanodine receptors are a family of intracellular Ca2+ release channel proteins, which exist as tetrameric complexes of large ( approximately 5000 amino acid residue) polypeptide monomers. As well as controlling striated muscle contraction and neurotransmitter release, these channel proteins have been implicated in several pathological states. In order to characterise ryanodine receptors in various tissues, mouse monoclonal antibodies were developed against the type 1 isoform isolated from skeletal muscle. Several of these antibodies recognise ryanodine receptor in skeletal muscle, as well as high molecular weight (k-HMW) protein in kidney microsomes. Like the ryanodine receptor, the k-HMW protein binds 45Ca2+ and sediments as a large complex upon sucrose density-gradient centrifugation. In contrast, the k-HMW protein does not bind ryanodine and is glycosylated. Furthermore, monoclonal and polyclonal antibodies generated against purified k-HMW protein do not recognise skeletal muscle ryanodine receptor. Characterisation of a cDNA clone encoding part of the k-HMW protein revealed that it is likely to be the rabbit homologue of human megalin, an autoimmune antigen in membranous glomerulonephritis. Potential consequences of immunological similarities between ryanodine receptors and megalin are discussed in terms of autoimmune disease.
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PMID:Autoimmune antigen megalin displays similarities with skeletal muscle ryanodine receptor/Ca2+ release channel. 1034 Dec 94