Chloride-dependent sarcoplasmic reticulum Ca2+ release correlates with increased Ca2+ activation of ryanodine receptors

被引:30
作者
Fruen, BR [1 ]
Kane, PK [1 ]
Mickelson, JR [1 ]
Louis, CF [1 ]
机构
[1] UNIV MINNESOTA,DEPT BIOCHEM,ST PAUL,MN 55108
关键词
D O I
10.1016/S0006-3495(96)79445-6
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The mechanism by which chloride increases sarcoplasmic reticulum (SR) Ca2+ permeability was investigated. In the presence of 3 mu M Ca2+, Ca2+ release from Ca-45(2+)-loaded SR vesicles prepared from porcine skeletal muscle was increased approximately 4-fold when the media contained 150 mM chloride versus 150 mM propionate, whereas in the presence of 30 nM Ca2+, Ca2+ release was similar in the chloride- and the propionate-containing media. Ca2+-activated [H-3]ryanodine binding to skeletal muscle SR was also increased (2- to 10-fold) in media in which propionate or other organic anions were replaced with chloride; however, chloride had little or no effect on cardiac muscle SR Ca-45(2+) release or [H-3]ryanpdine binding. Ca2+-activated [H-3]ryanodine binding was increased similar to 4.5-fold after reconstitution of skeletal muscle RYR protein into liposomes, and [H-3]ryanodine binding to reconstituted RYR protein was similar in chloride- and propionate- containing media, suggesting that the sensitivity of the RYR protein to changes in the anionic composition of the media may be diminished upon reconstitution. Together, our results demonstrate a close correlation between chloride-dependent increases in SR Ca2+ permeability and increased Ca2+ activation of skeletal muscle RYR channels. We postulate that media containing supraphysiological concentrations of chloride or other inorganic anions may enhance skeletal muscle RYR activity by favoring a conformational state of the channel that exhibits increased activation by Ca2+ in comparison to the Ca2+ activation exhibited by this channel in native membranes in the presence of physiological chloride (less than or equal to 10 mM). Transitions to this putative Ca2+-activatable state may thus provide a mechanism for controlling the activation of RYR channels in skeletal muscle.
引用
收藏
页码:2522 / 2530
页数:9
相关论文
共 35 条
[32]   MECHANISM OF CHLORIDE-DEPENDENT RELEASE OF CA2+ IN THE SARCOPLASMIC-RETICULUM OF RABBIT SKELETAL-MUSCLE [J].
SUKHAREVA, M ;
MORRISSETTE, J ;
CORONADO, R .
BIOPHYSICAL JOURNAL, 1994, 67 (02) :751-765
[33]  
Sukhareva M., 1996, Biophysical Journal, V70, pA168
[34]   CONFORMATIONAL-CHANGES IN THE JUNCTIONAL FOOT PROTEIN CA2+ RELEASE CHANNEL MEDIATE DEPOLARIZATION-INDUCED CA2+ RELEASE FROM SARCOPLASMIC-RETICULUM [J].
YANO, M ;
ELHAYEK, R ;
IKEMOTO, N .
JOURNAL OF BIOLOGICAL CHEMISTRY, 1995, 270 (07) :3017-3021
[35]   EFFECTS OF PERCHLORATE ON DEPOLARIZATION-INDUCED CONFORMATIONAL-CHANGES IN THE JUNCTIONAL FOOT PROTEIN AND CA2+ RELEASE FROM SARCOPLASMIC-RETICULUM [J].
YANO, M ;
ELHAYEK, R ;
IKEMOTO, N .
BIOCHEMISTRY, 1995, 34 (39) :12584-12589