Title: Transverse Tubular System - an overview | ScienceDirect Topics
Headings: Transverse Tubular System
Transverse Tubular System
Cardiovascular Physiology
Transverse Tubules
Ion Channel Trafficking
T-Tubules
Functional Organization of Vertebrate Plasma Membrane
2.4 T-tubules, physiology, and disease
Skeletal Muscle
T-tubules Are Surface Invaginations; the SR Is an Internal Membrane System
Cardiac Rhythm
4.2.1 Ca++ Regulation
Cardiovascular Physiology
Membrane Depolarization and Activator Calcium
Structure and Function of Calcium Release Channels
2 T Tubules and CRUs Revert to More Primitive Forms Under Pathological Conditions
Ion Channel Trafficking in the Heart
Ca V 1.2 Channel Trafficking in the Heart
Ca V 1.2 Forward Trafficking in Normal Heart Physiology
Ca V 1.2 Forward Trafficking in Heart Pathophysiology
Accessory Proteins Involved in Ca V 1.2 Targeted Delivery
T-Tubules and Ca V 1.2 Regulation in Normal Heart Physiology
T-Tubules and Ca V 1.2 Regulation in Heart Pathophysiology
Ca V 1.2 Internalization
Muscles
Coupling Action Potentials to Contraction
Skeletal Muscle Excitability
AIII Further Evidence that the T-Tubules Fire Na + -Dependent AP s

Content: Localization of LTCCs to T-tubules is critical in bringing LTCCs to the vicinity of calcium sense and release channel RyR at SR membrane. Approximation of LTCCs and RyRs form a functional microdomain, the cardiac dyads, which are the individual calcium-releasing units in cardiomyocytes. As discussed earlier, Targeted Delivery also applies to Cav1.2 channel localization to T-tubule surface, which requires a membrane scaffolding protein BIN1. 26 Interestingly, BIN1 also forms minifolds within T-tubules, affecting extracellular ion diffusion thereby controlling the driving force of Cav1.2 channel activity. 6 BIN1-folded subdomains within T-tubules may also limit LTCC lateral diffusion once the channels are inserted into T-tubule membrane, to maintain functional LTCC-RyR dyads. Therefore, BIN1-like membrane scaffold proteins may help localize particular pools of ion channel proteins to membrane subdomains for compartmentalized regulation of ion channel activity and function. Similarly, ankyrin B can play a role similar to BIN1 in clustering NCX/NKA/InsP3 complex to microdomains distinct from the dyads. 71 Integrity of NCX/NKA/InsP3 complex is critical in removing calcium from the clefts between T-tubule surface and SR membrane, facilitating calcium decline during relaxation. Therefore, intracellular calcium equilibrium can be achieved by balancing calcium entry through LTCC clustered at BIN1-membrane and calcium removal by NCX anchored at ankyrin B-induced membrane. View chapter Purchase book
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