scholarly journals Activation and labelling of the purified skeletal muscle ryanodine receptor by an oxidized ATP analogue

1995 ◽  
Vol 308 (1) ◽  
pp. 119-125 ◽  
Author(s):  
M Hohenegger ◽  
A Herrmann-Frank ◽  
M Richter ◽  
F Lehmann-Horn

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.

2002 ◽  
Vol 367 (2) ◽  
pp. 423-431 ◽  
Author(s):  
Martin HOHENEGGER ◽  
Josef SUKO ◽  
Regina GSCHEIDLINGER ◽  
Helmut DROBNY ◽  
Andreas ZIDAR

Calcium is a universal second messenger. The temporal and spatial information that is encoded in Ca2+-transients drives processes as diverse as neurotransmitter secretion, axonal outgrowth, immune responses and muscle contraction. Ca2+-release from intracellular Ca2+ stores can be triggered by diffusible second messengers like InsP3, cyclic ADP-ribose or nicotinic acid—adenine dinucleotide phosphate (NAADP). A target has not yet been identified for the latter messenger. In the present study we show that nanomolar concentrations of NAADP trigger Ca2+-release from skeletal muscle sarcoplasmic reticulum. This was due to a direct action on the Ca2+-release channel/ryanodine receptor type-1, since in single channel recordings, NAADP increased the open probability of the purified channel protein. The effects of NAADP on Ca2+-release and open probability of the ryanodine receptor occurred over a similar concentration range (EC5030nM) and were specific because (i) they were blocked by Ruthenium Red and ryanodine, (ii) the precursor of NAADP, NADP, was ineffective at equimolar concentrations, (iii) NAADP did not affect the conductance and reversal potential of the ryanodine receptor. Finally, we also detected an ADP-ribosyl cyclase activity in the sarcoplasmic reticulum fraction of skeletal muscle. This enzyme was not only capable of synthesizing cyclic GDP-ribose but also NAADP, with an activity of 0.25nmol/mg/min. Thus, we conclude that NAADP is generated in the vicinity of type 1 ryanodine receptor and leads to activation of this ion channel.


2010 ◽  
Vol 109 (3) ◽  
pp. 830-839 ◽  
Author(s):  
Chengju Tian ◽  
Chun Hong Shao ◽  
Danielle S. Fenster ◽  
Mark Mixan ◽  
Debra J. Romberger ◽  
...  

Skeletal muscle weakness is a reported ailment in individuals working in commercial hog confinement facilities. To date, specific mechanisms responsible for this symptom remain undefined. The purpose of this study was to assess whether hog barn dust (HBD) contains components that are capable of binding to and modulating the activity of type 1 ryanodine receptor Ca2+-release channel (RyR1), a key regulator of skeletal muscle function. HBD collected from confinement facilities in Nebraska were extracted with chloroform, filtered, and rotary evaporated to dryness. Residues were resuspended in hexane-chloroform (20:1) and precipitates, referred to as HBDorg, were air-dried and studied further. In competition assays, HBDorg dose-dependently displaced [3H]ryanodine from binding sites on RyR1 with an IC50 of 1.5 ± 0.1 μg/ml ( Ki = 0.4 ± 0.0 μg/ml). In single-channel assays using RyR1 reconstituted into a lipid bilayer, HBDorg exhibited three distinct dose-dependent effects: first it increased the open probability of RyR1 by increasing its gating frequency and dwell time in the open state, then it induced a state of reduced conductance (55% of maximum) that was more likely to occur and persist at positive holding potentials, and finally it irreversibly closed RyR1. In differentiated C2C12 myotubes, addition of HBD triggered a rise in intracellular Ca2+ that was blocked by pretreatment with ryanodine. Since persistent activation and/or closure of RyR1 results in skeletal muscle weakness, these new data suggest that HBD is responsible, at least in part, for the muscle ailment reported by hog confinement workers.


2000 ◽  
Vol 278 (3) ◽  
pp. C601-C611 ◽  
Author(s):  
Edward M. Balog ◽  
Bradley R. Fruen ◽  
Patricia K. Kane ◽  
Charles F. Louis

Inorganic phosphate (Pi) accumulates in the fibers of actively working muscle where it acts at various sites to modulate contraction. To characterize the role of Pi as a regulator of the sarcoplasmic reticulum (SR) calcium (Ca2+) release channel, we examined the action of Pi on purified SR Ca2+ release channels, isolated SR vesicles, and skinned skeletal muscle fibers. In single channel studies, addition of Pi to the cis chamber increased single channel open probability ( P o; 0.079 ± 0.020 in 0 Pi, 0.157 ± 0.034 in 20 mM Pi) by decreasing mean channel closed time; mean channel open times were unaffected. In contrast, the ATP analog, β,γ-methyleneadenosine 5′-triphosphate (AMP-PCP), enhanced P o by increasing single channel open time and decreasing channel closed time. Pi stimulation of [3H]ryanodine binding by SR vesicles was similar at all concentrations of AMP-PCP, suggesting Pi and adenine nucleotides act via independent sites. In skinned muscle fibers, 40 mM Pi enhanced Ca2+-induced Ca2+ release, suggesting an in situ stimulation of the release channel by high concentrations of Pi. Our results support the hypothesis that Pi may be an important endogenous modulator of the skeletal muscle SR Ca2+ release channel under fatiguing conditions in vivo, acting via a mechanism distinct from adenine nucleotides.


1994 ◽  
Vol 267 (3) ◽  
pp. H1010-H1016 ◽  
Author(s):  
A. Boraso ◽  
A. J. Williams

The effect of hydrogen peroxide (H2O2) on the sheep cardiac sarcoplasmic reticulum (SR) Ca(2+)-release channel has been investigated under voltage-clamp conditions after incorporation of native membrane vesicles into planar phospholipid bilayers. In the presence of micromolar activating calcium concentrations on the cytosolic side of the membrane, H2O2 (3-5 mM) increased open probability of the channels. H2O2 did not affect the conductance of the channel or the response to activating compounds, such as ATP and caffeine. H2O2 did not alter the inhibitory response to magnesium or the modification of channels by ryanodine. At subactivating calcium concentrations (approximately 45 pM) on the cytosolic side of the membrane, 5 mM H2O2 was still able to open the channel. Analysis of single-channel open and closed lifetimes suggested that H2O2 had a direct effect on the gating mechanism of the channel. Open probability of the SR Ca(2+)-release channel is reduced by millimolar concentrations of dithiothreitol, a sulfhydryl-protecting compound, in a concentration-dependent manner. In conclusion, it is probable that H2O2 activates the SR Ca(2+)-release channel via an oxidation of cysteine thiol groups in the channel protein.


1997 ◽  
Vol 73 (4) ◽  
pp. 1904-1912 ◽  
Author(s):  
S.R. Chen ◽  
P. Leong ◽  
J.P. Imredy ◽  
C. Bartlett ◽  
L. Zhang ◽  
...  

2007 ◽  
Vol 402 (2) ◽  
pp. 349-357 ◽  
Author(s):  
Takashi Murayama ◽  
Toshiharu Oba ◽  
Hiroshi Hara ◽  
Kikuo Wakebe ◽  
Noriaki Ikemoto ◽  
...  

We have demonstrated recently that CICR (Ca2+-induced Ca2+ release) activity of RyR1 (ryanodine receptor 1) is held to a low level in mammalian skeletal muscle (‘suppression’ of the channel) and that this is largely caused by the interdomain interaction within RyR1 [Murayama, Oba, Kobayashi, Ikemoto and Ogawa (2005) Am. J. Physiol. Cell Physiol. 288, C1222–C1230]. To test the hypothesis that aberration of this suppression mechanism is involved in the development of channel dysfunctions in MH (malignant hyperthermia), we investigated properties of the RyR1 channels from normal and MHS (MH-susceptible) pig skeletal muscles with an Arg615→Cys mutation using [3H]ryanodine binding, single-channel recordings and SR (sarcoplasmic reticulum) Ca2+ release. The RyR1 channels from MHS muscle (RyR1MHS) showed enhanced CICR activity compared with those from the normal muscle (RyR1N), although there was little or no difference in the sensitivity to several ligands tested (Ca2+, Mg2+ and adenine nucleotide), nor in the FKBP12 (FK506-binding protein 12) regulation. DP4, a domain peptide matching the Leu2442–Pro2477 region of RyR1 which was reported to activate the Ca2+ channel by weakening the interdomain interaction, activated the RyR1N channel in a concentration-dependent manner, and the highest activity of the affected channel reached a level comparable with that of the RyR1MHS channel with no added peptide. The addition of DP4 to the RyR1MHS channel produced virtually no further effect on the channel activity. These results suggest that stimulation of the RyR1MHS channel caused by affected inter-domain interaction between regions 1 and 2 is an underlying mechanism for dysfunction of Ca2+ homoeostasis seen in the MH phenotype.


2000 ◽  
Vol 279 (5) ◽  
pp. C1366-C1374 ◽  
Author(s):  
Toshiharu Oba ◽  
Tatsuya Ishikawa ◽  
Takashi Murayama ◽  
Yasuo Ogawa ◽  
Mamoru Yamaguchi

We examined the effect of low concentrations of H2O2 on the Ca2+-release channel/ryanodine receptor (RyR) to determine if H2O2 plays a physiological role in skeletal muscle function. Sarcoplasmic reticulum vesicles from frog skeletal muscle and type 1 RyRs (RyR1) purified from rabbit skeletal muscle were incorporated into lipid bilayers. Channel activity of the frog RyR was not affected by application of 4.4 mM (0.02%) ethanol. Open probability ( P o) of such ethanol-treated RyR channels was markedly increased on subsequent addition of 10 μM H2O2. Increase of H2O2to 100 μM caused a further increase in channel activity. Application of 4.4 mM ethanol to 10 μM H2O2-treated RyRs activated channel activity. Exposure to 10 or 100 μM H2O2 alone, however, failed to increase P o. Synergistic action of ethanol and H2O2 was also observed on the purified RyR1 channel, which was free from FK506 binding protein (FKBP12). H2O2 at 100–500 μM had no effect on purified channel activity. Application of FKBP12 to the purified RyR1 drastically decreased channel activity but did not alter the effects of ethanol and H2O2. These results suggest that H2O2 may play a pathophysiological, but probably not a physiological, role by directly acting on skeletal muscle RyRs in the presence of ethanol.


1986 ◽  
Vol 88 (5) ◽  
pp. 573-588 ◽  
Author(s):  
J S Smith ◽  
R Coronado ◽  
G Meissner

A high-conductance (100 pS in 53 mM trans Ca2+) Ca2+ channel was incorporated from heavy-density skeletal muscle sarcoplasmic reticulum (SR) fractions into planar lipid bilayers of the Mueller-Rudin type. cis Ca2+ in the range of 2-950 microM increased open probability (Po) in single channel records without affecting open event lifetimes. Millimolar ATP was found to be as good as or better than Ca2+ in activation; however, both Ca2+ and ATP were required to fully activate the channel, i.e., to bring Po = 1. Exponential fits to open and closed single channel lifetimes suggested that the channel may exist in many distinct states. Two open and two closed states were identified when the channel was activated by either Ca2+ or ATP alone or by Ca2+ plus nucleotide. Mg2+ was found to permeate the SR Ca channel in a trans-to-cis direction such that iMg2+/iCa2+ = 0.40. cis Mg2+ was inhibitory and in single channel recordings produced an unresolvable flickering of Ca- and nucleotide-activated channels. At nanomolar cis Ca2+, 4 microM Mg2+ completely inhibited nucleotide-activated channels. In the presence of 2 microM cis Ca2+, the nucleotide-activated macroscopic Ba conductance was inhibited by cis Mg2+ with an IC50 equal to 1.5 mM.


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