Residue Gln4863 within a Predicted Transmembrane Sequence of the Ca2+ Release Channel (Ryanodine Receptor) Is Critical for Ryanodine Interaction

Despite the pivotal role of ryanodine in ryanodine receptor (RyR) research, the molecular basis of ryanodine-RyR interaction remains largely undefined. We investigated the role of the proposed transmembrane helix TM10 in ryanodine interaction and channel function. Each amino acid residue within the TM10 sequence, 4844IIFDITFFFFVIVILLAIIQGLII4867, of the mouse RyR2 was mutated to either alanine or glycine. Mutants were expressed in human embryonic kidney 293 cells, and their properties were assessed. Mutations D4847A, F4850A, F4851A, L4858A, L4859A, and I4866A severely curtailed the release of intracellular Ca2+ in human embryonic kidney 293 cells in response to extracellular caffeine and diminished [3H]ryanodine binding to cell lysates. Mutations F4846A, T4849A, I4855A, V4856A, and Q4863A eliminated or markedly reduced [3H]ryanodine binding, but cells expressing these mutants responded to extracellular caffeine by releasing stored Ca2+. Interestingly these two groups of mutants, each with similar properties, are largely located on opposite sides of the predicted TM10 helix. Single channel analyses revealed that mutation Q4863A dramatically altered the kinetics and apparent affinity of ryanodine interaction with single RyR2 channels and abolished the effect of ryanodol, an analogue of ryanodine, whereas the single channel conductance of the Q4863A mutant and its responses to caffeine, ATP, and Mg2+ were comparable to those of the wild type channels. Furthermore the effect of ryanodine on single Q4863A mutant channels was influenced by the transmembrane holding potential. Together these results suggest that the TM10 sequence and in particular the Q4863 residue constitute an important determinant of ryanodine interaction. Despite the pivotal role of ryanodine in ryanodine receptor (RyR) research, the molecular basis of ryanodine-RyR interaction remains largely undefined. We investigated the role of the proposed transmembrane helix TM10 in ryanodine interaction and channel function. Each amino acid residue within the TM10 sequence, 4844IIFDITFFFFVIVILLAIIQGLII4867, of the mouse RyR2 was mutated to either alanine or glycine. Mutants were expressed in human embryonic kidney 293 cells, and their properties were assessed. Mutations D4847A, F4850A, F4851A, L4858A, L4859A, and I4866A severely curtailed the release of intracellular Ca2+ in human embryonic kidney 293 cells in response to extracellular caffeine and diminished [3H]ryanodine binding to cell lysates. Mutations F4846A, T4849A, I4855A, V4856A, and Q4863A eliminated or markedly reduced [3H]ryanodine binding, but cells expressing these mutants responded to extracellular caffeine by releasing stored Ca2+. Interestingly these two groups of mutants, each with similar properties, are largely located on opposite sides of the predicted TM10 helix. Single channel analyses revealed that mutation Q4863A dramatically altered the kinetics and apparent affinity of ryanodine interaction with single RyR2 channels and abolished the effect of ryanodol, an analogue of ryanodine, whereas the single channel conductance of the Q4863A mutant and its responses to caffeine, ATP, and Mg2+ were comparable to those of the wild type channels. Furthermore the effect of ryanodine on single Q4863A mutant channels was influenced by the transmembrane holding potential. Together these results suggest that the TM10 sequence and in particular the Q4863 residue constitute an important determinant of ryanodine interaction. Ryanodine receptors (RyRs) 1The abbreviations used are: RyRryanodine receptorHEKhuman embryonic kidneyTMtransmembraneCHAPS3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonatewtwild typeGSTglutathione S-transferaseFKBP12.6FK506-binding protein, 12.6 kDa.1The abbreviations used are: RyRryanodine receptorHEKhuman embryonic kidneyTMtransmembraneCHAPS3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonatewtwild typeGSTglutathione S-transferaseFKBP12.6FK506-binding protein, 12.6 kDa. are a family of intracellular Ca2+ release channels located in the sarco(endo)plasmic reticulum of a variety of cells. They play an essential role in various cellular functions including excitation-contraction coupling, fertilization, and apoptosis (1Berridge M.J. Lipp P. Bootman M.D. Nat. Rev. Mol. Cell. Biol. 2000; 1: 11-21Crossref PubMed Scopus (4319) Google Scholar, 2Coronado R. Morrissette J. Sukhareva M. Vaughan D.M. Am. J. Physiol. 1994; 266: C1485-C1504Crossref PubMed Google Scholar, 3Meissner G. Annu. Rev. Physiol. 1994; 56: 485-508Crossref PubMed Scopus (834) Google Scholar, 4Ogawa Y. Crit. Rev. Biochem. Mol. Biol. 1994; 29: 229-274Crossref PubMed Scopus (227) Google Scholar, 5Sutko J.L. Airey J.A. Welch W. Ruest L. Pharmacol. Rev. 1997; 49: 53-98PubMed Google Scholar, 6Franzini-Armstrong C. Protasi F. Physiol. Rev. 1997; 77: 699-729Crossref PubMed Scopus (585) Google Scholar, 7Fill M. Copello J.A. Physiol. Rev. 2002; 82: 893-922Crossref PubMed Scopus (868) Google Scholar). Three RyR isoforms, RyR1, RyR2, and RyR3, are expressed in mammalian tissues. Mutations in the RyR1 gene have been linked to two human diseases, malignant hyperthermia and central core disease (8Mickelson J.R. Louis C.F. Physiol. Rev. 1996; 76: 537-592Crossref PubMed Scopus (258) Google Scholar, 9Loke J. MacLennan D.H. Am. J. Med. 1998; 104: 470-486Abstract Full Text Full Text PDF PubMed Scopus (171) Google Scholar, 10Dirksen R. Avila G. Trends Cardiovasc. Med. 2002; 12: 189Crossref PubMed Scopus (100) Google Scholar), while mutations in the RyR2 genes are associated with polymorphic ventricular tachycardia and arrhythmogenic right ventricular cardiomyopathy type 2 (11Marks A. Priori S. Memmi M. Kontula K. Laitinen P. J. Cell. Physiol. 2002; 190: 1-6Crossref PubMed Scopus (166) Google Scholar, 12Scoote M. Williams A. Cardiovasc. Res. 2002; 56: 359-372Crossref PubMed Scopus (51) Google Scholar). To understand the impact of the disease-causing mutations and hence the molecular and cellular basis of the diseases, detailed knowledge of the structure-function relationships of RyRs is required. ryanodine receptor human embryonic kidney transmembrane 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate wild type glutathione S-transferase FK506-binding protein, 12.6 kDa. ryanodine receptor human embryonic kidney transmembrane 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate wild type glutathione S-transferase FK506-binding protein, 12.6 kDa. One of the most widely used probes for studying the structure and function of RyRs is ryanodine, a plant alkaloid. The high affinity and specificity of the interaction of ryanodine with RyRs has facilitated the identification, purification, and cloning of the channel (2Coronado R. Morrissette J. Sukhareva M. Vaughan D.M. Am. J. Physiol. 1994; 266: C1485-C1504Crossref PubMed Google Scholar, 3Meissner G. Annu. Rev. Physiol. 1994; 56: 485-508Crossref PubMed Scopus (834) Google Scholar, 4Ogawa Y. Crit. Rev. Biochem. Mol. Biol. 1994; 29: 229-274Crossref PubMed Scopus (227) Google Scholar, 5Sutko J.L. Airey J.A. Welch W. Ruest L. Pharmacol. Rev. 1997; 49: 53-98PubMed Google Scholar). Ryanodine has also been used to investigate the structural changes associated with channel gating and the mechanisms of ion conduction. Large ryanodine-induced conformational changes in the three-dimensional structure of RyR, in particular in the cytoplasmic assembly, have been observed (13Orlova E.V. Serysheva I.I. van Heel M. Hamilton S.L. Chiu W. Nat. Struct. Biol. 1996; 3: 547-552Crossref PubMed Scopus (146) Google Scholar). By monitoring the actions of ryanodine on single RyR channels it has been established that this ligand causes profound alterations in channel function. Interactions of ryanodine with a high affinity site on the channel induce the occurrence of a reduced conductance state with increased open probability, producing an overall effect of channel activation. In the presence of high micromolar to millimolar concentrations of ryanodine the RyR channel closes (5Sutko J.L. Airey J.A. Welch W. Ruest L. Pharmacol. Rev. 1997; 49: 53-98PubMed Google Scholar, 14Williams A.J. West D.J. Sitsapesan R. Q. Rev. Biophys. 2001; 34: 61-104Crossref PubMed Scopus (107) Google Scholar). While the functional effects of ryanodine have been well characterized, the structural basis of the action of ryanodine is largely undefined. To identify the determinants of ryanodine-RyR interaction within the ryanodine molecule, a large number of ryanodine derivatives (ryanoids) have been generated, and their binding properties have been characterized. The affinity and kinetics of interaction with RyR of different ryanoids were found to vary considerably. Unlike ryanodine, which modifies RyR in an irreversible manner on the time scale of single channel experiments, some ryanoids exhibit a reversible effect on single RyR channel function. These reversible ryanoids have provided useful probes for studying the mechanisms of ryanoid-RyR interaction and have been used to demonstrate that ryanoid-RyR interaction is influenced by transmembrane voltage (15Tinker A. Sutko J.L. Ruest L. Deslongchamps P. Welch W. Airey J.A. Gerzon K. Bidasee K.R. Besch Jr., H.R. Williams A.J. Biophys. J. 1996; 70: 2110-2119Abstract Full Text PDF PubMed Scopus (51) Google Scholar, 16Tanna B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 1998; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 2000; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. PubMed Scopus Google Scholar). analyses of the binding properties of various ryanoids have revealed that the the of the ryanodine is for high affinity ryanodine binding to In to the on the ryanodine are also in binding to RyR (5Sutko J.L. Airey J.A. Welch W. Ruest L. Pharmacol. Rev. 1997; 49: 53-98PubMed Google Scholar). The molecular determinants of ryanodine binding in the RyR with those in the ryanodine and functional have the ryanodine binding site to the the of RyR C. A. D.H. C. Y. Hamilton S.L. J. Biol. 1994; Full Text PDF PubMed Google Scholar, P. M.J. J. Biol. 1994; Full Text PDF PubMed Google Scholar, J. J. Biophys. J. 1997; Full Text PDF PubMed Scopus Google Scholar). in of a of the high affinity ryanodine binding site in RyR in a located in a transmembrane and and F. J. K. M. G. MacLennan D.H. J. Biol. Full Text PDF PubMed Google Scholar), Mutations in this or markedly high affinity [3H]ryanodine binding to RyR, that this an essential determinant of ryanodine interaction M. P. L. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar, L. L. A. C. G. Biophys. J. 2000; Full Text Full Text PDF PubMed Scopus Google Scholar, MacLennan D.H. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). The to the determinants of ryanodine interaction with RyR of the ryanodine are in ryanodine ryanodine with in the of RyR P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar), determinants of binding most in that the of the RyR on the of the RyR A.J. West D.J. Sitsapesan R. Q. Rev. Biophys. 2001; 34: 61-104Crossref PubMed Scopus (107) Google Scholar), have proposed that the central of the RyR which is in by the TM10 determinants for ryanodine interaction P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar). To this have a of the of the TM10 in ryanodine interaction and RyR channel function. We have mutated each residue in the TM10 sequence and the effects of the mutations by monitoring and ryanodine-induced release of intracellular Ca2+ in cells and by binding of [3H]ryanodine to RyR in cell lysates. We have that mutations in the TM10 the response of RyR to caffeine ryanodine and dramatically the binding of We have also that a single within TM10 dramatically the kinetics and affinity of ryanodine interaction with single RyR2 channels. These that the TM10 is an essential determinant of ryanodine interaction with of this has been in R. J. C. L. Biophys. J. Scholar). was was was and plant were and were was (5Sutko J.L. Airey J.A. Welch W. Ruest L. Pharmacol. Rev. 1997; 49: 53-98PubMed Google Scholar). and mutations were the proposed transmembrane helix TM10 of the mouse ryanodine receptor by the 77: PubMed Scopus Google The a mutation in the TM10 was the and was the mouse RyR2 Each mutation was by The of mutations and within the proposed of RyR2 has been M. P. L. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar). cells on in for were with of wild type or mutant RyR2 the of Ca2+ J. Scholar). and 2 in of cells were P. J. Physiol. 2001; PubMed Scopus Google and were with that was with and with of for The were with plant and a 2 2 2 and each time for The to the were by the of of P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google and for The were by R. J. B. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). The were to for in the presence of to J. S. A. 76: PubMed Scopus Google Scholar). The was for with and The was with the and each time for with The was with the and with for each time for the were by the and the [3H]ryanodine binding to cell was P. J. Physiol. 2001; PubMed Scopus Google with some binding was in a of of binding of cell caffeine, and the for The binding was with of and and was with The were and the associated with the were by binding was by [3H]ryanodine binding in the presence of binding were in of Ryanodine with Single Q4863A interaction of ryanodine with Q4863A mutant channels was B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. PubMed Scopus Google Scholar). In in the and were single channel and were used to the The apparent for and of ryanodine interaction were the in the and the and The were used to the voltage and the of and and and are the a particular voltage and and is the of the of the of and holding a with and and and The voltage of the is The was the and Single Ca2+ in cells was the Ca2+ P. J. Physiol. 2001; PubMed Scopus Google Scholar). RyR2 and mutant were cell by and were used for single channel P. J. Physiol. 2001; PubMed Scopus Google Scholar). and of Mutants in the TM10 proposed transmembrane TM10 of amino acid to F. J. K. M. G. MacLennan D.H. J. Biol. Full Text PDF PubMed Google the of in TM10 the To investigate the role of the TM10 in ryanodine-RyR mutated each amino acid residue in the TM10 sequence to alanine in the of residue to by the To the of these mutants, cells were with or mutant RyR2 The expressed and mutant RyR2 were by to cell by and with an in TM10 mutants were expressed in cells, and their of were comparable with that of the of the was cells with the These results also that TM10 mutants the to of Mutations in the TM10 on the impact of the mutations on ryanodine-RyR interaction by [3H]ryanodine binding to each TM10 mutant in cell lysates. binding was in the presence of Ca2+ and caffeine, a which the RyR channel is and hence is for the of in [3H]ryanodine to the of RyR2 TM10 Mutants and binding in of of the In mutants and binding of or of RyR2 2 and mutants were expressed in cells a comparable the of [3H]ryanodine binding to this of mutants was to These that mutations in the TM10 of RyR2 have a profound on the binding of binding and caffeine and ryanodine response of TM10 in a and Ryanodine of the and the high affinity ryanodine binding site is the RyR channel is in an open B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 1998; PubMed Scopus Google Scholar, A. M. M.J. K. Hamilton S.L. Mol. Pharmacol. Google Scholar, S. Williams A. Biophys. PubMed Scopus Google Scholar, M.J. Hamilton S.L. J. Biol. Full Text PDF PubMed Google Scholar), the profound in [3H]ryanodine binding to some TM10 mutants that these mutations channels that open the used in binding In the mutant is a functional Ca2+ release To the functional state of the TM10 mutant channels that binding of [3H]ryanodine and ryanodine-induced release of intracellular Ca2+ in cells expressing and mutant cells were with a Ca2+ Ca2+ were by the and the of extracellular caffeine or in a in in cells expressing RyR2 was by caffeine and expressing mutants and release of Ca2+ in the presence of either caffeine that these mutants Ca2+ release channels in cells. Furthermore ryanodine-induced Ca2+ release was also in cells expressing the mutants and that these mutant channels to ryanodine in cells their of [3H]ryanodine binding in cell lysates. the or ryanodine-induced intracellular Ca2+ release was in cells expressing mutants or expressed in comparable to these mutants alterations in channel by caffeine and binding and the responses to caffeine and ryanodine of cells expressing RyR2 and TM10 mutants are in that TM10 mutants that [3H]ryanodine binding in of of Ca2+ release channels in cells and that cells with the or ryanodine-induced Ca2+ release of the mutants in the TM10 sequence, is the mutant that [3H]ryanodine binding and ryanodine-induced Ca2+ release but Ca2+ release and These suggest that residue is to play a role in ryanodine-RyR interaction. of the on the and of Ryanodine with Single RyR2 of residue in ryanodine-RyR interaction was investigated by monitoring the effect of ryanodine on single mutant channels. We have that the interaction of ryanodine with single RyR2 channels a in open and a in conductance P. L. J. Biol. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). the of of ryanodine RyR2 is that the interaction irreversible on the time scale of a single channel to either [3H]ryanodine binding to the mutant channel or ryanodine-induced Ca2+ release in cells expressing this mutant that the mutation has effects on ryanodine interaction with with this found that the interaction of ryanodine with single mutant channels was a single mutant channel by Ca2+ in the of these observed the and open The of ryanodine to the of the channel to the occurrence of of gating in which conductance was reduced and increased with that the of is channel B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 1998; PubMed Scopus Google Scholar), the of Ca2+ to increased and the occurrence of ryanodine observed ryanodine of single mutant channels was reversible in to the irreversible effect of ryanodine on single RyR2 channels. mutation dramatically the kinetics of ryanodine interaction with The responses of single mutant channels to well were similar to those of the RyR2 channels. The single mutant channels were by caffeine, and and by Mg2+ The relationships and holding for and of the mutant channel are in of conductance of the and are and and are comparable to those of the of RyR2 channels M. P. L. J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). While the mutation a profound in the kinetics of ryanodine interaction it to alterations in channel or the of gating by of Ryanodine with Single has been that the effects of reversible ryanoids on single RyR2 channels are on the transmembrane holding (15Tinker A. Sutko J.L. Ruest L. Deslongchamps P. Welch W. Airey J.A. Gerzon K. Bidasee K.R. Besch Jr., H.R. Williams A.J. Biophys. J. 1996; 70: 2110-2119Abstract Full Text PDF PubMed Scopus (51) Google Scholar, 16Tanna B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 1998; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 2000; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. PubMed Scopus Google Scholar). the of ryanodine action is also on the transmembrane to the of ryanodine action on single RyR2 channels. The of ryanodine of single mutant channels to the voltage of ryanodine To this the single channel of the mutant in the presence of ryanodine and the in the and various transmembrane holding These were used to the of ryanodine and To the of on the of of ryanodine single channels were to by Ca2+ 2 caffeine by of in a transmembrane holding of the channel of gating and of which was by a in The occurrence and of the gating the transmembrane to the channel in the These are of voltage on ryanodine of single channels. of this voltage was by the and and various transmembrane holding that the of of ryanodine with the channel while the of increased the transmembrane holding to The voltage of and is and a voltage of ryanodine interaction of ryanodine interaction with single mutant channels is influenced by transmembrane holding potential. that the transmembrane holding in were the to the of the while the cytoplasmic of the channel was the of single channel was the to the cytoplasmic of the also that the voltage used in this is the opposite of that used in the the voltage of interaction with RyR2 (15Tinker A. Sutko J.L. Ruest L. Deslongchamps P. Welch W. Airey J.A. Gerzon K. Bidasee K.R. Besch Jr., H.R. Williams A.J. Biophys. J. 1996; 70: 2110-2119Abstract Full Text PDF PubMed Scopus (51) Google Scholar, 16Tanna B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 1998; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 2000; PubMed Scopus Google Scholar, B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. PubMed Scopus Google Scholar). The the and the of Ryanodine with reversible interaction ryanodine and single channels also to the and properties of ryanodine interaction. The and the of the in are and The and of high affinity [3H]ryanodine binding to RyR2 were and P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar, C. P. M. S. PubMed Scopus Google Scholar, Mol. Pharmacol. Google Scholar, MacLennan D.H. J. Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). The and for ryanodine interaction with single mutant channels are and those of ryanodine binding to RyR2 that the mutation has an effect on the on the of ryanodine interaction with that the affinity of ryanodine interaction with the channel was also influenced by transmembrane holding potential. The the were reduced the holding on the of the channel to The or the is apparent affinity of ryanodine interaction with single mutant channels is that of ryanodine binding to RyR2 by [3H]ryanodine binding P. J. Physiol. 2001; PubMed Scopus Google Scholar). the mutation dramatically the affinity of ryanodine interaction with RyR2 by the of the on of Single RyR2 the mutation also the kinetics and affinity of interaction of ryanoids with RyR2, the effect of ryanodol, an analogue of ryanodine that the the on RyR2 and mutant channels. a single RyR2 channel by Ca2+ and of to the the channel to of gating and of gating by a in conductance and a in These are with of the kinetics and functional of interaction of with RyR2 channels B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. 2000; PubMed Scopus Google Scholar). To the of interaction with the mutant increased the of the channel to by caffeine and in and the of a high of to the mutant channel to conductance those with the RyR2 channels by a of the ligand either or transmembrane holding the mutation the effect of on single RyR2 channels. We have proposed that the of the RyR channel and the these two transmembrane a with the established structure of the channel A.J. West D.J. Sitsapesan R. Q. Rev. Biophys. 2001; 34: 61-104Crossref PubMed Scopus (107) Google Scholar). In this proposed structure of the RyR TM10 to the helix of and the TM10 of each a the of the the of the TM10 in channel function and ryanodine-RyR interaction has been In the have the impact of mutations in the TM10 on various of RyR2 function. results the that the TM10 an important determinant of ryanodine interaction and channel function. on their response to caffeine and ryanodine and their to the TM10 mutants The of these of and These mutants of [3H]ryanodine binding and responded to and to the of TM10 mutants, which of [3H]ryanodine binding and or response to caffeine or The severely [3H]ryanodine binding with this of mutants is to a in channel activation. of mutants and These mutant channels or [3H]ryanodine but or ryanodine-induced Ca2+ these mutants Ca2+ release channels in cells, the of [3H]ryanodine binding to these mutants in cell is to to the of the ryanodine binding that ryanodine some release of stored intracellular Ca2+ in cells expressing these mutant channels that these ryanodine open these channels to some the of [3H]ryanodine binding in the that the ryanodine-RyR to a of [3H]ryanodine binding The of the changes a detailed The mutant is the of the of TM10 while Ca2+ release channel [3H]ryanodine concentrations 2 and to and ryanodine-induced Ca2+ that this mutation has for ryanodine interaction. with this mutation altered the kinetics and affinity of ryanodine interaction with single RyR2 channels. The interaction of ryanodine with single mutant channels is The apparent affinity of the interaction of ryanodine with the mutant channel is that of ryanodine with the RyR2 the conductance of the mutant channel and its response to of caffeine, ATP, and were comparable to those of single RyR2 channels. Furthermore mutation abolished the effect of on single RyR2 channels. These that residue an essential determinant of ryanoid-RyR interaction. The of [3H]ryanodine binding and ryanodine-induced Ca2+ release with this mutant is to the altered kinetics and markedly reduced affinity of ryanodine interaction. is the results of that mutations within the TM10 of RyR2 have effects on channel function and ryanodine interaction. The molecular mechanisms by which mutations in TM10 ryanodine binding and channel are The different of the mutations are to to their in the structure of the TM10 sequence, which is In an to the structural basis for the impact of the mutations have the TM10 an is apparent the that most of the 2 which have in profound alterations in channel including and but are located on of the helix the most of the and which functional channels but high affinity ryanodine including and but are located on the opposite of the helix The of mutants with similar properties that the TM10 helix for channel and ryanodine The results of also that the effect of ryanodine, the effect of reversible on single RyR2 channel function is influenced by the transmembrane holding potential. The of ryanodine with and single channels with transmembrane potential. of the voltage of interaction of ryanoids with different that the voltage of ryanoid-RyR interaction results a in receptor affinity a of changes in the RyR the of a or the voltage the RyR channel B. Welch W. Ruest L. Sutko J.L. Williams A.J. J. Physiol. PubMed Scopus Google Scholar). The molecular determinants for this in receptor and affinity that the mutant the voltage of interaction that residue for ryanodine binding, is to in conformational of the of RyR to the structural basis of this binding analyses of a number of ryanoids have established while the the a structural on the ryanodine to high affinity with structural in the RyR to in high affinity ryanodine In of this have that mutations in the RyR2 to the channel sequence functional channels but high affinity [3H]ryanodine binding P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar). that the sequence within the of RyR2 an essential determinant of ryanodine binding P. M. L. Biophys. J. 2002; 82: Full Text Full Text PDF PubMed Scopus Google Scholar). The results of the that the TM10 determinant of ryanodine interaction. is the determinants on the RyR2 and ryanodine with each that the mutation the effect of on RyR2 channels suggest that residue or TM10 is a determinant in the interaction with the on the ryanodine has of the effects of mutations in the TM10 and of RyR2 on of channel function by various ryanoids of structure to the and mechanisms in the ryanodine and We for and on analyses of interaction with

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.