Related Experiment Video
Updated: Jan 1, 2026

Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles
Published on: October 15, 2014
Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains
Muriel Sébastien1, Perrine Aubin1, Jacques Brocard1
1Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France.
Abstract:
In skeletal muscle, proteins of the calcium release complex responsible for the excitation-contraction (EC) coupling are exclusively localized in specific reticulum-plasma membrane (ER-PM) contact points named triads. The CRC protein triadin (T95) is localized in the sarcoplasmic reticulum (SR) subdomain of triads where it forms large multimers. However, the mechanisms leading to the steady-state accumulation of T95 in these specific areas of SR are largely unknown. To visualize T95 dynamics, fluorescent chimeras were expressed in triadin knockout myotubes, and their mobility was compared with the mobility of Sec61β, a membrane protein of the SR unrelated to the EC coupling process. At all stages of skeletal muscle cells differentiation, we show a permanent flux of T95 diffusing in the SR membrane. Moreover, we find evidence that a longer residence time in the ER-PM contact point is due to the transmembrane domain of T95 resulting in an overall triad localization.
Related Concept Videos
Excitation-Contraction Coupling in Skeletal Muscles
When an action...
Cross-bridge Cycle
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....
Actin and Myosin in Muscle Contraction
Microscopic Anatomy of Skeletal Muscles
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
The Sarcomere
Each...

