Title: T-Tubule - an overview | ScienceDirect Topics
Headings: T-Tubule
T-Tubule
Ion Channel Trafficking
T-Tubules
Skeletal Muscle
T-tubules Are Surface Invaginations; the SR Is an Internal Membrane System
Structure and Function of Calcium Release Channels
2 T Tubules and CRUs Revert to More Primitive Forms Under Pathological Conditions
Muscles
Coupling Action Potentials to Contraction
The Cellular Basis of Cardiac Contractility
The SR Releases Stored Ca 2+ to Activate Contraction
Disorders of Muscle Excitability
Calcium couples muscle membrane excitation to filament contraction
Muscle physiology
Excitation–contraction coupling
EXERCISE | Muscle
Voltage-dependent Sarcoplasmic Reticulum Ca 2+ Release

Content: Since CRU anchor T tubules to the myofibrils, both would result in T network disarrangement. Further, is the disorder due to a regression from a fully differentiated architecture to a more primitive one, or is the expression of an ongoing process of degeneration and regeneration, where the latter does not achieve a final result? A partial answer to some of these questions comes from the observation that reduced e–c coupling effectiveness in experimental cardiac hypertrophy may be interpreted as a reduction in functional coupling of CaV1.2 and RyR2 channels ( Gomez et al., 1997) and traced to an apparent disconnection between RyR and CaV1.2 clusters in the failing heart ( Song et al., 2006 ). A similar, although more limited, separation of RyR and CaV1.2 clusters is found in a pan triadin null mouse model, where expression levels of all junctional proteins are decreased, with an impairment of e–c coupling and susceptibility to ventricular arrhythmia ( Chopra et al., 2009 ). T tubules in fast fibers of skeletal muscles respond in a very sensitive manner to a number of interventions that also influence the relationship of T tubules to SR and the frequency of CRUs. Disordered T networks with frequent longitudinal extensions; evidence of new T tubule formation and multiple SR–T tubule contacts (pentads, heptads) are found in denervated ( Takekura, Tamaki, Nishizawa, & Kasuga, 2003 );