Coupled gating between cardiac calcium release channels (ryanodine receptors)

SO Marx, J Gaburjakova, M Gaburjakova… - Circulation …, 2001 - Am Heart Assoc
SO Marx, J Gaburjakova, M Gaburjakova, C Henrikson, K Ondrias, AR Marks
Circulation research, 2001Am Heart Assoc
Excitation-contraction coupling in heart muscle requires the activation of Ca2+-release
channels/type 2 ryanodine receptors (RyR2s) by Ca2+ influx. RyR2s are arranged on the
sarcoplasmic reticular membrane in closely packed arrays such that their large cytoplasmic
domains contact one another. We now show that multiple RyR2s can be isolated under
conditions such that they remain physically coupled to one another. When these coupled
channels are examined in planar lipid bilayers, multiple channels exhibit simultaneous …
Abstract
—Excitation-contraction coupling in heart muscle requires the activation of Ca2+-release channels/type 2 ryanodine receptors (RyR2s) by Ca2+ influx. RyR2s are arranged on the sarcoplasmic reticular membrane in closely packed arrays such that their large cytoplasmic domains contact one another. We now show that multiple RyR2s can be isolated under conditions such that they remain physically coupled to one another. When these coupled channels are examined in planar lipid bilayers, multiple channels exhibit simultaneous gating, termed “coupled gating.” Removal of the regulatory subunit, the FK506 binding protein (FKBP12.6), functionally but not physically uncouples multiple RyR2 channels. Coupled gating between RyR2 channels may be an important regulatory mechanism in excitation-contraction coupling as well as in other signaling pathways involving intracellular Ca2+ release.
Am Heart Assoc