scholarly journals RyR1-related myopathy mutations in ATP and calcium binding sites impair channel regulation

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Qi Yuan ◽  
Haikel Dridi ◽  
Oliver B. Clarke ◽  
Steven Reiken ◽  
Zephan Melville ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Weakness ◽  
Binding Sites ◽  
Calcium Binding ◽  
Atp Binding ◽  
Release Channel ◽  
Channel Regulation ◽  
Adenine Ring ◽  
High Concentrations ◽  
Inherited Mutations

AbstractThe type 1 ryanodine receptor (RyR1) is an intracellular calcium (Ca2+) release channel on the sarcoplasmic/endoplasmic reticulum that is required for skeletal muscle contraction. RyR1 channel activity is modulated by ligands, including the activators Ca2+ and ATP. Patients with inherited mutations in RyR1 may exhibit muscle weakness as part of a heterogeneous, complex disorder known as RYR1-related myopathy (RYR1-RM) or more recently termed RYR1-related disorders (RYR1-RD). Guided by high-resolution structures of skeletal muscle RyR1, obtained using cryogenic electron microscopy, we introduced mutations into putative Ca2+ and ATP binding sites and studied the function of the resulting mutant channels. These mutations confirmed the functional significance of the Ca2+ and ATP binding sites identified by structural studies based on the effects on channel regulation. Under normal conditions, Ca2+ activates RyR1 at low concentrations (µM) and inhibits it at high concentrations (mM). Mutations in the Ca2+-binding site impaired both activating and inhibitory regulation of the channel, suggesting a single site for both high and low affinity Ca2+-dependent regulation of RyR1 function. Mutation of residues that interact with the adenine ring of ATP abrogated ATP binding to the channel, whereas mutating residues that interact with the triphosphate tail only affected the degree of activation. In addition, patients with mutations at the Ca2+ or ATP binding sites suffer from muscle weakness, therefore impaired RyR1 channel regulation by either Ca2+ or ATP may contribute to the pathophysiology of RYR1-RM in some patients.

Mechanisms of Pi regulation of the skeletal muscle SR Ca2+ release channel

2000 ◽  
Vol 278 (3) ◽  
pp. C601-C611 ◽  
Author(s):  
Edward M. Balog ◽  
Bradley R. Fruen ◽  
Patricia K. Kane ◽  
Charles F. Louis
Keyword(s):  
Skeletal Muscle ◽  
Single Channel ◽  
Adenine Nucleotides ◽  
Muscle Fibers ◽  
Open Probability ◽  
Release Channel ◽  
High Concentrations ◽  
Channel Open Time ◽  
Stimulation Of

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.

Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum

1997 ◽  
Vol 82 (2) ◽  
pp. 447-452 ◽  
Author(s):  
Terence G. Favero ◽  
, Anthony C. Zable ◽  
, David Colter ◽  
Jonathan J. Abramson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Single Channel ◽  
Channel Activity ◽  
Release Channel ◽  
Muscle Lactate ◽  
Tension Development ◽  
Contraction Coupling ◽  
Single Channel Activity ◽  
High Concentrations

Favero, Terence G., Anthony C. Zable, David Colter, and Jonathan J. Abramson. Lactate inhibits Ca2+-activated Ca2+-channel activity from skeletal muscle sarcoplasmic reticulum. J. Appl. Physiol. 82(2): 447–452, 1997.—Sarcoplasmic reticulum (SR) Ca2+-release channel function is modified by ligands that are generated during about of exercise. We have examined the effects of lactate on Ca2+- and caffeine-stimulated Ca2+ release, [3H]ryanodine binding, and single Ca2+-release channel activity of SR isolated from rabbit white skeletal muscle. Lactate, at concentrations from 10 to 30 mM, inhibited Ca2+- and caffeine-stimulated [3H]ryanodine binding to and inhibited Ca2+- and caffeine-stimulated Ca2+ release from SR vesicles. Lactate also inhibited caffeine activation of single-channel activity in bilayer reconstitution experiments. These findings suggest that intense muscle activity, which generates high concentrations of lactate, will disrupt excitation-contraction coupling. This may lead to decreases in Ca2+ transients promoting a decline in tension development and contribute to muscle fatigue.

scholarly journals Properties of the non-specific calcium-binding sites of rabbit skeletal-muscle myosin

1980 ◽  
Vol 185 (1) ◽  
pp. 265-268 ◽  
Author(s):  
J Wikman-Coffelt
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Binding Sites ◽  
Calcium Binding ◽  
Light Chains ◽  
Binding Properties ◽  
Skeletal Muscle Myosin ◽  
Heavy Chains ◽  
Calcium Binding Sites ◽  
Muscle Myosin

The non-specific Ca2+-binding sites of skeletal-muscle myosin are located on the light chains; with the dissociation of light chains there is a corresponding decrease in the number of Ca2+-binding sites on light-chain-deficient myosin. The released light chains have a decreased binding affinity. Myosin heavy chains indirectly influence the Ca2+-binding properties of light chains by increasing the affinity of light chains for bivalent cations; this influence varies with pH. Because of light-chain dissociation at low Ca2+ and/or Mg2+ concentrations, anomalies may exist when analyses of non-specific Ca2+-binding properties of myosin are assessed by dialysis equilibrium.

A Mechanism for Both Capacitative Ca2+ Entry and Excitation-Contraction Coupled Ca2+ Release by the Sarcoplasmic Reticulum of Skeletal Muscle Cells

2002 ◽  
Vol 227 (6) ◽  
pp. 425-431 ◽  
Author(s):  
Mohammad Naimul Islam ◽  
Bisni Narayanan ◽  
Raymond S. Ochs
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Muscle Cells ◽  
Cell Types ◽  
Release Channel ◽  
Close Proximity ◽  
High Concentrations ◽  
Combined Channel ◽  
Uncompetitive Inhibitor

We have previously established that L6 skeletal muscle cell cultures display capacitative calcium entry (CCE), a phenomenon established with other cells in which Ca2+ uptake from outside cells increases when the endoplasmic reticulum (sarcoplasmic reticulum in muscle, or SR) store is decreased. Evidence for CCE rested on the use of thapsigargin (Tg), an inhibitor of the SR CaATPase and consequently transport of Ca2+ from cytosol to SR, and measurements of cytosolic Ca2+. When Ca2+ is added to Ca2+-free cells in the presence of Tg, the measured cytosolic Ca2+ rises. This has been universally interpreted to mean that as SR Ca2+ is depleted, exogenous Ca2+ crosses the plasma membrane, but accumulates in the cytosol due to CaATPase inhibition. Our goal in the present study was to examine CCE in more detail by measuring Ca2+ in both the SR lumen and the cytosol using established fluorescent dye techniques for both. Surprisingly, direct measurement of SR Ca2+ in the presence of Tg showed an increase in luminal Ca2+ concentration in response to added exogenous Ca2+. While we were able to reproduce the conventional demonstration of CCE—an increase of Ca2+ in the cytosol in the presence of thapsigargin—we found that this process was inhibited by the prior addition of ryanodine (Ry), which inhibits the SR Ca2+ release channel, the ryanodine receptor (RyR). This was also unexpected if Ca2+ enters the cytosol first. When Ca2+ was added prior to Ry, the later was unable to exert any inhibition. This implies a competitive interaction between Ca2+ and Ry at the RyR. In addition, we found a further paradox: we had previously found Ry to be an uncompetitive inhibitor of Ca2+ transport through the RyR during excitation-contraction coupling. We also found here that high concentrations of Ca2+ inhibited its own uptake, a known feature of the RyR. We confirmed that Ca2+ enters the cells through the dihydropyridine receptor (DHPR, also known as the L-channel) by demonstrating inhibition by diltiazem. A previous suggestion to the contrary had used Mn2+ in place of direct Ca2+ measurements; we showed that Mn2+ was not inhibited by diltiazem and was not capacitative, and thus not an appropriate probe of Ca2+ flow in muscle cells. Our findings are entirely explained by a new model whereby Ca2+ enters the SR from the extracellular space directly through a combined channel formed from the DHPR and the RyR. These are known to be in close proximity in skeletal muscle. Ca2+ subsequently appears in the cytosol by egress through a separate, unoccupied RyR, explaining Ry inhibition. We suggest that upon excitation, the DHPR, in response to the electrical field of the plasma membrane, shifts to an erstwhile-unoccupied receptor, and Ca2+ is released from the now open RyR to trigger contraction. We discuss how this model also resolves existing paradoxes in the literature, and its implications for other cell types.

scholarly journals Interaction between Ryanodine and Neomycin Binding Sites on Ca Release Channel from Skeletal Muscle Sarcoplasmic Reticulum

1996 ◽  
Vol 271 (14) ◽  
pp. 8387-8393 ◽  
Author(s):  
Jian Ping Wang ◽  
Dolores H. Needleman ◽  
Alexander B. Seryshev ◽  
Bahman Aghdasi ◽  
Kenneth J. Slavik ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Release Channel

scholarly journals Chloroform extract of hog barn dust modulates skeletal muscle ryanodine receptor calcium-release channel (RyR1)

2010 ◽  
Vol 109 (3) ◽  
pp. 830-839 ◽  
Author(s):  
Chengju Tian ◽  
Chun Hong Shao ◽  
Danielle S. Fenster ◽  
Mark Mixan ◽  
Debra J. Romberger ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptor ◽  
Muscle Weakness ◽  
Calcium Release ◽  
Single Channel ◽  
Calcium Release Channel ◽  
Open Probability ◽  
Skeletal Muscle Function ◽  
Release Channel ◽  
Skeletal Muscle Weakness

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.

scholarly journals Mutation Analysis of the Calcium Binding Site of Skeletal Muscle Ryanodine Receptor Calcium Release Channel

2019 ◽  
Vol 116 (3) ◽  
pp. 520a-521a
Author(s):  
Venkat R. Chirasani ◽  
Le Xu ◽  
Jordan S. Carter ◽  
Hannah G. Addis ◽  
Daniel A. Pasek ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Ryanodine Receptor ◽  
Mutation Analysis ◽  
Calcium Binding ◽  
Calcium Release ◽  
Calcium Release Channel ◽  
Calcium Binding Site ◽  
Release Channel

scholarly journals Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

1968 ◽  
Vol 52 (4) ◽  
pp. 622-642 ◽  
Author(s):  
Arselio P. Carvalho
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Local Anesthetics ◽  
Calcium Binding ◽  
Rabbit Skeletal Muscle ◽  
Cellular Membranes ◽  
Binding Properties ◽  
45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 - 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

Mutations to Gly2370, Gly2373 or Gly2375 in malignant hyperthermia domain 2 decrease caffeine and cresol sensitivity of the rabbit skeletal-muscle Ca2+-release channel (ryanodine receptor isoform 1)

2001 ◽  
Vol 360 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Guo Guang DU ◽  
Hideto OYAMADA ◽  
Vijay K. KHANNA ◽  
David H. MacLENNAN
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Malignant Hyperthermia ◽  
Ryanodine Receptor ◽  
Atp Binding ◽  
Regulatory Domain ◽  
Wild Type ◽  
Release Channel ◽  
Binding Motifs ◽  
Channel Opening

Mutations G2370A, G2372A, G2373A, G2375A, Y3937A, S3938A, G3939A and K3940A were made in two potential ATP-binding motifs (amino acids 2370–2375 and 3937–3940) in the Ca2+-release channel of skeletal-muscle sarcoplasmic reticulum (ryanodine receptor or RyR1). Activation of [3H]ryanodine binding by Ca2+, caffeine and ATP (adenosine 5′-[β,γ-methylene]triphosphate, AMP-PCP) was used as an assay for channel opening, since ryanodine binds only to open channels. Caffeine-sensitivity of channel opening was also assayed by caffeine-induced Ca2+ release in HEK-293 cells expressing wild-type and mutant channels. Equilibrium [3H]ryanodine-binding properties and EC50 values for Ca2+ activation of high-affinity [3H]ryanodine binding were similar between wild-type RyR1 and mutants. In the presence of 1mM AMP-PCP, Ca2+-activation curves were shifted to higher affinity and maximal binding was increased to a similar extent for wild-type RyR1 and mutants. ATP sensitivity of channel opening was also similar for wild-type and mutants. These observations apparently rule out sequences 2370–2375 and 3937–3940 as ATP-binding motifs. Caffeine or 4-chloro-m-cresol sensitivity, however, was decreased in mutants G2370A, G2373A and G2375A, whereas the other mutants retained normal sensitivity. Amino acids 2370–2375 lie within a sequence (amino acids 2163–2458) in which some eight RyR1 mutations have been associated with malignant hyperthermia and shown to be hypersensitive to caffeine and 4-chloro-m-cresol activation. By contrast, mutants G2370A, G2373A and G2375A are hyposensitive to caffeine and 4-chloro-m-cresol. Thus amino acids 2163–2458 form a regulatory domain (malignant hyperthermia regulatory domain 2) that regulates caffeine and 4-chloro-m-cresol sensitivity of RyR1.

Sign in / Sign up

Export Citation Format

Share Document