Journal article
Purified ryanodine receptor from skeletal muscle sarcoplasmic reticulum is the Ca2+-permeable pore of the calcium release channel
The Journal of biological chemistry, Vol.262(34), pp.16636-16643
1987
DOI: 10.1016/S0021-9258(18)49303-9
PMID: 2445748
Abstract
The ryanodine receptor of rabbit skeletal muscle sarcoplasmic reticulum was purified by immunoaffinity chromatography as a single approximately 450,000-Da polypeptide and it was shown to mediate single channel activity identical to that of the ryanodine-treated Ca2+ release channel of the sarcoplasmic reticulum. The purified receptor had a [3H]ryanodine binding capacity (Bmax) of 280 pmol/mg and a binding affinity (Kd) of 9.0 nM. [3H]Ryanodine binding to the purified receptor was stimulated by ATP and Ca2+ with a half-maximal stimulation at 1 mM and 8-9 microM, respectively. [3H]Ryanodine binding to the purified receptor was inhibited by ruthenium red and high concentrations of Ca2+ with an IC50 of 2.5 microM and greater than 1 mM, respectively. Reconstitution of the purified receptor in planar lipid bilayers revealed the Ca2+ channel activity of the purified receptor. Like the native sarcoplasmic reticulum Ca2+ channels treated with ryanodine, the purified receptor channels were characterized by (i) the predominance of long open states insensitive to Mg2+ and ruthenium red, (ii) a main slope conductance of approximately 35 pS and a less frequent 22 pS substate in 54 mM trans-Ca2+ or Ba2+, and (iii) a permeability ratio PBa or PCa/PTris = 8.7. The approximately 450,000-Da ryanodine receptor channel thus represents the long-term open "ryanodine-altered" state of the Ca2+ release channel from sarcoplasmic reticulum. We propose that the ryanodine receptor constitutes the physical pore that mediates Ca2+ release from the sarcoplasmic reticulum of skeletal muscle.
Details
- Title: Subtitle
- Purified ryanodine receptor from skeletal muscle sarcoplasmic reticulum is the Ca2+-permeable pore of the calcium release channel
- Creators
- Toshiaki Imagawa - Univ. Iowa, dep. physiology biophysics, Iowa City IA 52242, United StatesJeffrey S Smith - Univ. Iowa, dep. physiology biophysics, Iowa City IA 52242, United StatesRoberto Coronado - Univ. Iowa, dep. physiology biophysics, Iowa City IA 52242, United StatesKevin P Campbell - Univ. Iowa, dep. physiology biophysics, Iowa City IA 52242, United States
- Resource Type
- Journal article
- Publication Details
- The Journal of biological chemistry, Vol.262(34), pp.16636-16643
- DOI
- 10.1016/S0021-9258(18)49303-9
- PMID
- 2445748
- NLM abbreviation
- J Biol Chem
- ISSN
- 0021-9258
- eISSN
- 1083-351X
- Publisher
- American Society for Biochemistry and Molecular Biology; Bethesda, MD
- Language
- English
- Date published
- 1987
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Iowa Neuroscience Institute
- Record Identifier
- 9984068369402771
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