Related Experiment Video
Updated: Oct 8, 2026

Genetic and Biochemical Approaches for In Vivo and In Vitro Assessment of Protein Oligomerization: The Ryanodine Receptor Case Study
Published on: July 27, 2016
Native skeletal muscle dihydropyridine receptor exists as a supramolecular triad complex
1Department of Pharmacology, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Ireland.
Abstract:
One of the central elements of excitation-contraction coupling, the voltage-sensing dihydropyridine receptor, is believed to exist as a high-molecular-mass complex in the triad junction. Although freeze-fracture electron microscopical analysis suggests a tetrad complex, no direct biochemical evidence exists demonstrating the actual size of the native membrane complex. Using a combination of various two-dimensional gel electrophoresis techniques, we show here that the principal alpha1-subunit of the dihydropyridine receptor and its auxiliary alpha2-subunit form a triad complex of approximately 2800 kDa under native conditions. Established Ca2+-ATPase tetramers and calsequestrin monomers were employed for the internal standardization of the gel systems used. Thus, the large voltage-sensing complex appears to be tightly associated, since it does not disintegrate during subcellular fractionation and native electrophoresis procedures. Our findings support the cell biological hypothesis that native dihydropyridine receptor units form a tetrad structure within the transverse tubules.
Related Concept Videos
Excitation-Contraction Coupling in Skeletal Muscles
When an action potential...
Overview of Skeletal Muscle
Actin and Myosin in Muscle Contraction
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Cross-bridge Cycle
Transducer Mechanism: Enzyme-Linked Receptors
Major types that are helpful drug targets include:
