Selective modulation of coupled ryanodine receptors during microdomain activation of calcium/calmodulin-dependent kinase II in the dyadic cleft

Eef Dries, Virginie Bito, Ilse Lenaerts, Gudrun Antoons, Karin R. Sipido*, Niall Macquaide

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


RATIONALE: In ventricular myocytes of large mammals with low T-tubule density, a significant number of ryanodine receptors (RyRs) are not coupled to the sarcolemma; cardiac remodeling increases noncoupled RyRs.

OBJECTIVE: Our aim was to test the hypothesis that coupled and noncoupled RyRs have distinct microdomain-dependent modulation.

METHODS AND RESULTS: We studied single myocytes from pig left ventricle. The T-tubule network was analyzed in 3-dimension (3D) to measure distance to membrane of release sites. The rising phase of the Ca(2+) transient was correlated with proximity to the membrane (confocal imaging, whole-cell voltage-clamp, K5fluo-4 as Ca(2+) indicator). Ca(2+) sparks after stimulation were thus identified as resulting from coupled or noncoupled RyRs. We used high-frequency stimulation as a known activator of Ca(2+)/calmodulin-dependent kinase II. Spark frequency increased significantly more in coupled than in noncoupled RyRs. This specific modulation of coupled RyRs was abolished by the Ca(2+)/calmodulin-dependent kinase II blockers autocamtide-2-related inhibitory peptide and KN-93, but not by KN-92. Colocalization of Ca(2+)/calmodulin-dependent kinase II and RyR was not detectably different for coupled and noncoupled sites, but the F-actin disruptor cytochalasin D prevented the specific modulation of coupled RyRs. NADPH oxidase 2 inhibition by diphenyleneiodonium or apocynin, or global reactive oxygen species scavenging, also prevented coupled RyR modulation. During stimulated Ca(2+) transients, frequency-dependent increase of the rate of Ca(2+) rise was seen in coupled RyR regions only and abolished by autocamtide-2-related inhibitory peptide. After myocardial infarction, selective modulation of coupled RyR was lost.

CONCLUSIONS: Coupled RyRs have a distinct modulation by Ca(2+)/calmodulin-dependent kinase II and reactive oxygen species, dependent on an intact cytoskeleton and consistent with a local Ca(2+)/reactive oxygen species microdomain, and subject to modification with disease.

Original languageEnglish
Pages (from-to)1242-1252
Number of pages11
JournalCirculation Research
Issue number11
Publication statusPublished - 8 Nov 2013


  • Animals
  • Calcium/metabolism
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2/physiology
  • Disease Models, Animal
  • Imaging, Three-Dimensional
  • Membrane Microdomains/physiology
  • Microscopy, Confocal
  • Myocardial Infarction/metabolism
  • Myocytes, Cardiac/pathology
  • Patch-Clamp Techniques
  • Reactive Oxygen Species/metabolism
  • Ryanodine Receptor Calcium Release Channel/physiology
  • Sarcolemma/physiology
  • Sarcoplasmic Reticulum/metabolism
  • Swine


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