Characterization of Type 3 Ryanodine Receptor (RyR3) of Sarcoplasmic Reticulum from Rabbit Skeletal Muscles

Murayama, Takashi; Ogawa, Yasuo

doi:10.1074/jbc.272.38.24030

Cited by 70 publications

(74 citation statements)

References 44 publications

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“…The Ca 2+ dependence of WT RyR3 has been previously published based on immunoprecipitated protein and the resulting data fitted using a single-site model indicating monophasic activation of WT RyR3 by Ca 2+ [28] and [29]. Two significant methodological differences distinguish the present study.…”

Section: Resultsmentioning

confidence: 90%

Allosterically coupled calcium and magnesium binding sites are unmasked by ryanodine receptor chimeras

Voss

Allen

Pessah

et al. 2008

Biochemical and Biophysical Research Communications

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We studied cation regulation of wild type ryanodine receptor type 1 ( WT RyR1), type 3 ( WT RyR3) and RyR3/RyR1 chimeras (Ch) expressed in 1B5 dyspedic myotubes. Using [ 3 H]ryanodine binding to sarcoplasmic reticulum (SR) membranes, Ca 2+ titrations with WT RyR3 and three chimeras show biphasic activation that is allosterically coupled to attenuated inhibition relative to WT RyR1. Chimeras show biphasic Mg 2+ inhibition profiles at 3 and 10μM Ca 2+ , no observable inhibition at 20μM Ca 2+ and monophasic inhibition at 100μM Ca 2+ . Ca 2+ imaging of intact myotubes expressing Ch-4 exhibit caffeine-induced Ca 2+ transients with inhibition kinetics that are significantly slower than those expressing WT RyR1 or WT RyR3. Four new aspects of RyR regulation are evident: 1) high affinity (H) activation and low affinity (L) inhibition sites are allosterically coupled, 2) Ca 2+ facilitates removal of the inherent Mg 2+ block, 3) WT RyR3 exhibits reduced cooperativity between H activation sites when compared to WT RyR1, and 4) uncoupling of these sites in Ch-4 results in decreased rates of inactivation of caffeine-induced Ca transients.Keywords ryanodine receptors; calcium-induced calcium release; channel regulation Three isoforms of wild type ryanodine receptors ( WT RyR1, 2 and 3) are expressed in specialized regions of endoplasmic/sarcoplasmic reticulum (ER/SR) in most mammalian cells where they function as Ca 2+ Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Materials and Methods Chimeric RyR1/RyR3 constructsSpecific primers were designed for PCR amplification of the selected fragments using WT RyR1 as a template. Amplified fragments from WT RyR1 encoding aa 1681-2217 (Ch-17), 1924-2446 (Ch-21) and 1681-3770 (Ch-4) were inserted, in frame, into the endogenous restriction site(s) of HSV-RyR3 plasmid as described previously [20]. All chimeric constructs were cloned into the HSV-1 amplicon vector and packaged using a helper virus-free packaging system [22]. Cell culture, infection and membrane preparation1B5 myoblasts were cultured and differentiated into myotubes as described previously [20] and [23]. Plates with differentiated myotubes were infected with virion containing wild type and RyR1/RyR3 chimeric cDNA for 2 h and membrane extracts were prepared 36 h after infection. Myotubes were homogenized and membrane fractions obtained by differential centrifugation as described previously [24].[ cold buffer, placed into 5 ml scintillation cocktail (ScintiVerse; Fisher Scientific) and radioactivity counted. Equations for binding analysisCurve fitting was ...

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Section: Resultsmentioning

confidence: 90%

Allosterically coupled calcium and magnesium binding sites are unmasked by ryanodine receptor chimeras

Voss

Allen

Pessah

et al. 2008

Biochemical and Biophysical Research Communications

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“…Evidence that strongly suggests that solubilized receptors do indeed mimic reconstituted receptors when exposed to modulatory ligands comes from ryanodine binding experiments, which have been done using solubilized RyR3. Ryanodine is known to preferentially bind to the open form of the receptor over the closed form (41), and for solubilized RyR3, ryanodine binding is modulated by known receptor activators and inhibitors in much the same manner as channel gating in bilayer experiments (19,22).…”

Section: Open Versus Closed Ryr3 Reconstructionsmentioning

confidence: 99%

“…Reconstructions were determined for RyR3 under buffer conditions that should favor open and closed states of the receptor based upon conductance measurements on purified receptors following their incorporation into lipid bilayers (16,19,20,22). However, we cannot be certain that the solubilized RyR3 used for cryo-microscopy behaves exactly as do the receptors in a bilayer environment.…”

Section: Open Versus Closed Ryr3 Reconstructionsmentioning

confidence: 99%

Three-dimensional Structure of Ryanodine Receptor Isoform Three in Two Conformational States as Visualized by Cryo-electron Microscopy

Sharma¹,

Jeyakumar²,

Fleischer³

et al. 2000

Journal of Biological Chemistry

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Using cryo-electron microscopy and single particle image processing techniques, we present the first threedimensional reconstructions of isoform 3 of the ryanodine receptor/calcium release channel (RyR3). Reconstructions were carried out on images obtained from a purified, detergent-solubilized receptor for two different buffer conditions, which were expected to favor open and closed functional states of the channel. As for the heart (RyR2) and skeletal muscle (RyR1) receptor isoforms, RyR3 is a homotetrameric complex comprising two main components, a multidomain cytoplasmic assembly and a smaller (ϳ20% of the total mass) transmembrane region. Although the isoforms show structural similarities, consistent with the ϳ70% overall sequence identity of the isoforms, detailed comparisons of RyR3 with RyR1 showed one region of highly significant difference between them. This difference indicated additional mass present in RyR1, and it likely corresponds to a region of the RyR1 sequence (residues 1303-1406, known as diversity region 2) that is absent from RyR3. The reconstructions of RyR3 determined under "open" and "closed" conditions were similar to each other in overall architecture. A difference map computed between the two reconstructions reveals subtle changes in conformation at several widely dispersed locations in the receptor, the most prominent of which is a ϳ4°ro-tation of the transmembrane region with respect to the cytoplasmic assembly.

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“…It is clear that RyR1 is the key isoform in terms of skeletal muscle activation as many skeletal muscles, including some very fast ones, express only RyR1, proving that RyR1 alone can sustain effective e-c coupling (9,(13)(14)(15)(16). Only RyR1 is capable of forging the link with ␣1sDHPR necessary for skeletal muscle type e-c coupling and for the organization of four DHPRs into a tetrad (17).…”

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confidence: 99%

Type 3 ryanodine receptors of skeletal muscle are segregated in a parajunctional position

Felder

Franzini‐Armstrong

2002

Proc. Natl. Acad. Sci. U.S.A.

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A key event in skeletal muscle activation is the rapid release of Ca 2؉ from the sarcoplasmic reticulum (SR), the Ca 2؉ storage organelle in the muscle cell. The surface membrane͞transverse tubules and the SR form functional units (calcium release units containing one or two couplons or junctions), where the voltage-sensing dihydropyridine receptor of the surface membrane interacts with the SR Ca 2؉ release channel [ryanodine receptor (RyR)] and depolarization of the cell membrane is converted into Ca 2؉ release from the SR. Although RyR1 is the most important isoform in skeletal muscle, some muscles also express high levels of RyR3, an isoform with a wide tissue distribution. The cytoplasmic domains of RyRs are visible in the electron microscope as periodically disposed feet. We find that, in muscles containing only RyR1, feet are exclusively located over the junctional SR surface facing the surface membrane͞transverse tubule. In muscles containing RyR1 as well as RyR3, additional feet are located in lateral parajunctional regions immediately adjacent to junctional SR. Biochemical content of RyR3 and content of parajunctional feet are highly correlated in different muscles and the disposition of parajunctional versus junctional feet are notably different. On the basis of these two observations, we postulate that RyR3s are restricted to the parajunctional region, and thus their activation must be indirect and derivative during excitation-contraction coupling.

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Characterization of Type 3 Ryanodine Receptor (RyR3) of Sarcoplasmic Reticulum from Rabbit Skeletal Muscles

Cited by 70 publications

References 44 publications

Allosterically coupled calcium and magnesium binding sites are unmasked by ryanodine receptor chimeras

Allosterically coupled calcium and magnesium binding sites are unmasked by ryanodine receptor chimeras

Three-dimensional Structure of Ryanodine Receptor Isoform Three in Two Conformational States as Visualized by Cryo-electron Microscopy

Type 3 ryanodine receptors of skeletal muscle are segregated in a parajunctional position

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