Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UNIPROT:P21817 (RyR1)
1,154 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
...
PMID:The ryanodine receptor/calcium channel genes are widely and differentially expressed in murine brain and peripheral tissues. 787 12

Ryanodine receptors are key molecules in excitation-contraction coupling of skeletal muscle. They form the pore of the calcium release channel, which is regulated by Ca and ATP. Multiple proton titration sites are involved in controlling the different open states of the channel, as indicated by the following: i) the channel had a biphasic response to changes in proton concentrations around neutral pH; ii) the activities of the channel were inhibited by acidic pHs in a highly cooperative manner; and iii) the channel exhibited pronounced hysteresis to changes in pH. Four distinct conductance states can be identified in the single ryanodine-activated calcium release channel. The distribution of the multiple conductance states depends on the level of [Ca], ATP, and pH in the recording solution. The data are consistent with the multimeric structure of the skeletal muscle ryanodine receptor.
...
PMID:Highly cooperative and hysteretic response of the skeletal muscle ryanodine receptor to changes in proton concentrations. 794 77

In the present study, we have identified calmodulin binding sequences in the skeletal muscle ryanodine receptor Ca2+ release channel. Ligand overlays on RYR fusion proteins indicate that the skeletal muscle RYR contains three calmodulin binding regions defined by residues 2937-3225, 3546-3655, and 4425-4621. The RYR fusion protein PC28 (residues 2937-3225) bound calmodulin in the presence of EGTA and Ca2+, while RYR fusion protein PC26 (residues 3546-3655) exhibited strong calmodulin binding at 10 microM Ca2+. The RYR fusion protein PC15 (residues 4425-4621) did not bind calmodulin in the presence of either EGTA or 10-50 microM Ca2+. In the presence of 100-500 microM Ca2+, the RYR fusion protein PC15 exhibited an affinity for calmodulin of approximately 50 nM. Peptides RYR1 PM2 (residues 3610-3629) and RYR1 PM3 (4534-4552) encompassing putative RYR-calmodulin binding sites were synthesized. The synthetic peptides interacted directly with dansylcalmodulin as demonstrated by their capacity to affect the fluorescence emission of dansylcalmodulin. Missense mutation analysis indicates that the Lys and Arg residues are essential for calmodulin binding to the synthetic peptide RYR1 PM3. The RYR calmodulin binding site defined by peptide PM3 lies in the myoplasmic loop 2, a few residues upstream of the putative transmembrane segment M5; the other two calmodulin binding sites are next to the putative transmembrane segments M' and M''. Thus, the effect of calmodulin on Ca2+ release might involve the regulation of the putative transmembrane segments M5, M', and M''.
...
PMID:Identification and characterization of three calmodulin binding sites of the skeletal muscle ryanodine receptor. 804 9

We have shown previously that the skeletal muscle ryanodine receptor mRNA of approximately 16,000 nucleotides codes 5,037 amino acid residues constituting the calcium release channel in skeletal muscle. In this study, RNA blot hybridization analysis shows that the brain contains an RNA species with an estimated size of approximately 2,400 nucleotides hybridizable with the 3'-terminal region of the skeletal muscle ryanodine receptor cDNA. cDNA cloning and genome analysis indicated that two transcripts differing in their start sites are produced from the skeletal muscle ryanodine receptor gene in a tissue-specific fashion, and that the mRNA in brain may code the carboxyl-terminal region of the ryanodine receptor molecule. cDNA expression experiments suggested that the ATG triplet encoding Met4382 of the skeletal muscle ryanodine receptor can function as a translation initiation codon, and that the expressed protein composed of the carboxy terminal 656 amino acid residues of the receptor is located on the endoplasmic reticulum membrane.
...
PMID:A brain-specific transcript from the 3'-terminal region of the skeletal muscle ryanodine receptor gene. 809 30

Expression studies with skeletal and cardiac muscle cDNAs have suggested that the putative cytoplasmic loop region of the dihydropyridine receptor (DHPR) alpha 1 subunit between transmembrane repeats II and III (DCL) is a major determinant of the type of excitation-contraction coupling (skeletal or cardiac) in rescued dysgenic muscle cells (Tanabe, T., Beam, K. G., Adams, B. A., Niidome, T., and Numa, S. (1990) Nature 346, 567-569). In this study, the possibility of a direct functional interaction with the sarcoplasmic reticulum ryanodine receptor/Ca2+ release channel has been tested by expressing the DCLs of the mammalian skeletal and cardiac muscle DHPR alpha 1 subunit in Escherichia coli. The purified peptides activated the skeletal muscle ryanodine receptor/Ca2+ release channel in single channel and [3H]ryanodine binding measurements, by increasing channel open probability and the affinity of [3H]ryanodine binding, respectively. The two peptides did not activate the cardiac muscle Ca2+ release channel. Other proteins (polylysine, serum albumin) also increased [3H]ryanodine binding and Ca2+ release channel activity, but their activation mechanisms were distinguishable from DCLs. These results show that the II-III cytoplasmic loop of the skeletal and cardiac DHPR alpha 1 subunit functionally interacts with the skeletal, but not cardiac, muscle Ca2+ release channel. Furthermore, our studies suggest that in addition to the DHPR, the sarcoplasmic reticulum Ca2+ release channel may determine the type of E-C coupling that exists in muscle.
...
PMID:Activation of the skeletal muscle calcium release channel by a cytoplasmic loop of the dihydropyridine receptor. 812 2

Ryanodine receptors/Ca2+ release channels play an important role in regulating the intracellular free calcium concentrations in both muscle and nonmuscle cells. Ryanodine, a neutral plant alkaloid, specifically binds to and modulates these Ca2+ release channels. In the work described here, we characterize the interaction of a tritium-labeled, photoactivable derivative of ryanodine (3H-labeled 10-O-[3-(4-azidobenzamido)propionyl]ryanodine ([3H]ABRy)) with the ryanodine receptor of skeletal, cardiac, and brain membranes. Scatchard analysis demonstrates that this ligand binds to a single class of high affinity sites in skeletal muscle triads. Furthermore, competition binding assays of [3H]ryanodine with skeletal, cardiac, and brain membranes in the presence of increasing concentrations of unlabeled ABRy illustrate that this azido derivative of ryanodine is able to specifically displace [3H]ryanodine from its binding site(s). Analysis of the effects of Ca2+, ATP, and KCl on [3H]ABRy binding in triad membranes shows a similar modulation of binding to that seen in these membranes with [3H]ryanodine. Photoaffinity labeling of triads with [3H]ABRy resulted in specific and covalent incorporation of [3H]ABRy into a 565-kDa protein that was shown to be the skeletal muscle ryanodine receptor. Digestion of the labeled ryanodine receptor revealed a [3H]ABRy-labeled 76-kDa tryptic fragment that was identified with an antibody directed against the COOH-terminal of the receptor. These results demonstrate that the 76-kDa COOH-terminal tryptic fragment contains the high affinity binding site for ryanodine.
...
PMID:Photoaffinity labeling of the ryanodine receptor/Ca2+ release channel with an azido derivative of ryanodine. 817 31

The Ca2+ release channel of skeletal muscle sarcoplasmic reticulum is modulated in a biphasic manner by the plant alkaloid ryanodine and there are two distinct binding sites on this channel for ryanodine. The Ca2+ release channel is a homotetramer with a subunit of 5037 amino acids. The ability of sarcoplasmic reticulum membranes to bind [3H]ryanodine to the high affinity site is lost upon proteolysis with trypsin. [3H]Ryanodine, however, bound before proteolysis remains bound after trypsin digestion. If the high affinity site is first occupied with [3H]ryanodine and then 100 microM ryanodine is added to occupy the low affinity sites, almost all of [3H]ryanodine bound to the high affinity site remains bound after proteolysis. Proteolysis causes the solubilized Ca2+ release channel containing bound [3H]ryanodine to undergo four discrete shifts in sedimentation (30 S-->28 S-->26 S-->19 S-->14 S). Polypeptides having apparent molecular masses of 76, 66, 56, 45, 37, and 27 kDa can be identified in the 14 S complex. The 76-, 56-, 45-, and 27-kDa polypeptides have been partially sequenced from the NH2 terminus. In addition, the 76-, 66-, and 27-kDa fragments are recognized by an antibody to the last 9 amino acids at the carboxyl terminus of the skeletal muscle ryanodine receptor and the 76-, 66-, and 37-kDa fragments are recognized by an antibody to a peptide matching the sequence 4670-4685. The 56-kDa and the 45-kDa fragments are not Ca2+ release channel fragments. Both high and low affinity ryanodine binding sites are found in the 14 S complex and are, therefore, most likely located between Arg-4475 and the carboxyl terminus.
...
PMID:Localization of the high and low affinity [3H]ryanodine binding sites on the skeletal muscle Ca2+ release channel. 819 43

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.
...
PMID:Genomic organization of the porcine skeletal muscle ryanodine receptor (RYR1) gene coding region 4624 to 7929. 828 38

Calcium release from intracellular stores is the signal generated by numerous regulatory pathways including those mediated by hormones, neurotransmitters and electrical activation of muscle. Recently two forms of intracellular calcium release channels (CRCs) have been identified. One, the inositol 1,4,5-trisphosphate receptors (IP3Rs) mediate IP3-induced Ca2+ release and are believed to be present on the ER of most cell types. A second form, the ryanodine receptors (RYRs) of the sarcoplasmic reticulum, have evolved specialized functions relevant to muscle contraction and are the major CRCs found in striated muscles. Though structurally related, IP3Rs and RYRs have distinct physiologic and pharmacologic profiles. In the heart, where the dominant mechanism of intracellular calcium release during excitation-contraction coupling is Ca(2+)-induced Ca2+ release via the RYR, a role for IP3-mediated Ca2+ release has also been proposed. It has been assumed that IP3Rs are expressed in the heart as in most other tissues, however, it has not been possible to state whether cardiac IP3Rs were present in cardiac myocytes (which already express abundant amounts of RYR) or only in non-muscle cells within the heart. This lack of information regarding the expression and structure of an IP3R within cardiac myocytes has hampered the elucidation of the significance of IP3 signaling in the heart. In the present study we have used combined in situ hybridization to IP3R mRNA and immunocytochemistry to demonstrate that, in addition to the RYR, an IP3R is also expressed in rat cardiac myocytes. Immunoreactivity and RNAse protection have shown that the IP3R expressed in cardiac myocytes is structurally similar to the IP3R in brain and vascular smooth muscle. Within cardiac myocytes, IP3R mRNA levels were approximately 50-fold lower than that of the cardiac RYR mRNA. Identification of an IP3R in cardiac myocytes provides the basis for future studies designed to elucidate its functional role both as a mediator of pharmacologic and hormonal influences on the heart, and in terms of its possible interaction with the RYR during excitation-contraction coupling in the heart.
...
PMID:Inositol 1,4,5-trisphosphate receptor expression in cardiac myocytes. 838 5

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.
...
PMID:Characterization and photoaffinity labeling of the ATP binding site of the ryanodine receptor from skeletal muscle. 838 21


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---