The 30 S lobster skeletal muscle Ca2+ release channel (ryanodine receptor) has functional properties distinct from the mammalian channel proteins

• Published in: The Journal of biological chemistry 1992-08, Vol.267 (22), p.15893-15901
• Main Authors: JEONG-HO SEOK, LE XU, KRAMARCY, N. R, SEALOCK, R, MEISSNER, G
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Calcium - metabolism; Calcium Channels - physiology; Cell receptors; Cell structures and functions; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Immunoblotting; Kinetics; Mammals; Membrane Potentials - drug effects; Miscellaneous; Molecular and cellular biology; Molecular Weight; Muscles - physiology; Nephropidae; Receptors, Cholinergic - isolation & purification; Receptors, Cholinergic - metabolism; Receptors, Cholinergic - physiology; Ryanodine - metabolism; Ryanodine - pharmacology; Ryanodine Receptor Calcium Release Channel
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)49618-X

The 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (Chaps)-solubilized ryanodine receptor (RyR) of lobster skeletal muscle has been isolated by rate density centrifugation as a 30 S protein complex. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the purified 30 S receptor revealed a single high molecular weight protein band with a mobility intermediate between those of the mammalian skeletal and cardiac M(r) 565,000 RyR polypeptides. Immunoblot analysis showed no or only minimal cross-reactivity with the rabbit skeletal and canine cardiac RyR polypeptides. By immunofluorescence the lobster RyR was localized to the junctions of the A-I bands. Following planar lipid bilayer reconstitution of the purified 30 S lobster RyR, single channel K+ and Ca2+ currents were observed which were modified by ryanodine and optimally activated by millimolar concentrations of cis (cytoplasmic) Ca2+. Vesicle-45Ca2+ flux measurements also indicated an optimal activation of the lobster Ca2+ channel by millimolar Ca2+, whereas 45Ca2+ efflux from mammalian skeletal and cardiac muscle sarcoplasmic reticulum (SR) vesicles is optimally activated by micromolar Ca2+. Further, mammalian muscle SR Ca2+ release activity is modulated by Mg2+ and ATP, whereas neither ligand appreciably affected 45Ca2+ efflux from lobster SR vesicles. These results suggested that lobster and mammalian muscle express immunologically and functionally distinct SR Ca2+ release channel protein complexes.