HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 286/1/C179    most recent 00176.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (16) Citing Articles via Google Scholar Google Scholar Articles by Lee, E. H. Articles by Allen, P. D. Search for Related Content PubMed PubMed Citation Articles by Lee, E. H. Articles by Allen, P. D.

MUSCLE CELL BIOLOGY AND CELL MOTILITY

Conformational coupling of DHPR and RyR1 in skeletal myotubes is influenced by long-range allosterism: evidence for a negative regulatory module

¹Department of Anesthesia Research, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; ²Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616; ³Laboratory of Cellular Physiology, CeSI Center for Research on Ageing, Università degli Studi G. d'Annunzio, 66013 Chieti, Italy; and ⁴Department of Life Science, Kwangju Institute of Science and Technology, Kwangju 500-712, Korea

Submitted 1 May 2003 ; accepted in final form 11 September 2003

Four ryanodine receptor type 1 and 2 chimeras (R4, R9, R10, and R16) and their respective wild-type ryanodine receptors (type 1 and 2; wtRyR1 and wtRyR2) were expressed in dyspedic 1B5 to identify possible negative regulatory modules of the Ca²⁺ release channel that are under the influence of the dihydropyridine receptor (DHPR). Responses of intact 1B5 myotubes expressing each construct to caffeine in the absence or presence of either La³⁺ and Cd²⁺ or the organic DHPR blocker nifedipine were determined by imaging single 1B5 myotubes loaded with fluo 4. The presence of La³⁺ and Cd²⁺ or nifedipine in the external medium at concentrations known to block Ca²⁺ entry through the DHPRs significantly decreased the caffeine EC₅₀ of wtRyR1 (2.80 ± 0.12 to 0.83 ± 0.09 mM; P < 0.05). On the other hand, DHPR blockade did not significantly alter the caffeine EC₅₀ values of wtRyR2, chimeras R10 and R16, whereas the caffeine EC₅₀ values of chimeras R4 and R9 were significantly increased (1.27 ± 0.05 to 2.60 ± 0.16 mM, and 1.15 ± 0.03 to 2.11 ± 0.32 mM, respectively; P < 0.05). Despite the fact that all the chimeras form fully functional Ca²⁺ release channels in situ, sarcoplasmic reticulum (SR) containing R4, R10, and R16 did not possess high-affinity binding of [³H]ryanodine regardless of Ca²⁺ concentration. These results suggest the presence of an interaction between RyR1 and the DHPR, which is not present in RyR2, that contributes negative control of SR Ca²⁺ release induced by direct agonists such as caffeine. Although we were unable to define the negative module using RyR1-RyR2 chimeras, they further demonstrated that the RyR is very sensitive to long-range allosterism.

ryanodine receptor type 1; dihydropyridine receptor; excitation-contraction coupling; negative module

This article has been cited by other articles:

				T. Yang, E. Esteve, I. N. Pessah, T. F. Molinski, P. D. Allen, and J. R. Lopez Elevated resting [Ca2+]i in myotubes expressing malignant hyperthermia RyR1 cDNAs is partially restored by modulation of passive calcium leak from the SR Am J Physiol Cell Physiol, May 1, 2007; 292(5): C1591 - C1598. [Abstract] [Full Text] [PDF]

				N. Weisleder, M. Brotto, S. Komazaki, Z. Pan, X. Zhao, T. Nosek, J. Parness, H. Takeshima, and J. Ma Muscle aging is associated with compromised Ca2+ spark signaling and segregated intracellular Ca2+ release J. Cell Biol., August 28, 2006; 174(5): 639 - 645. [Abstract] [Full Text] [PDF]

				Y. Hirata, M. Brotto, N. Weisleder, Y. Chu, P. Lin, X. Zhao, A. Thornton, S. Komazaki, H. Takeshima, J. Ma, et al. Uncoupling Store-Operated Ca2+ Entry and Altered Ca2+ Release from Sarcoplasmic Reticulum through Silencing of Junctophilin Genes Biophys. J., June 15, 2006; 90(12): 4418 - 4427. [Abstract] [Full Text] [PDF]

				J. Zhou, J. Yi, L. Royer, B. S. Launikonis, A. Gonzalez, J. Garcia, and E. Rios A probable role of dihydropyridine receptors in repression of Ca2+ sparks demonstrated in cultured mammalian muscle Am J Physiol Cell Physiol, February 1, 2006; 290(2): C539 - C553. [Abstract] [Full Text] [PDF]

				X.-F. Hu, X. Liang, K.-Y. Chen, H. Xie, Y. Xu, P.-H. Zhu, and J. Hu Modulation of the Oligomerization of Isolated Ryanodine Receptors by their Functional States Biophys. J., September 1, 2005; 89(3): 1692 - 1699. [Abstract] [Full Text] [PDF]

				Y. W. Zhou, S. A. Oak, S. E. Senogles, and H. W. Jarrett Laminin-{alpha}1 globular domains 3 and 4 induce heterotrimeric G protein binding to {alpha}-syntrophin's PDZ domain and alter intracellular Ca2+ in muscle Am J Physiol Cell Physiol, February 1, 2005; 288(2): C377 - C388. [Abstract] [Full Text] [PDF]

				R. G. Weiss, K. M. S. O'Connell, B. E. Flucher, P. D. Allen, M. Grabner, and R. T. Dirksen Functional analysis of the R1086H malignant hyperthermia mutation in the DHPR reveals an unexpected influence of the III-IV loop on skeletal muscle EC coupling Am J Physiol Cell Physiol, October 1, 2004; 287(4): C1094 - C1102. [Abstract] [Full Text] [PDF]