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: 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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URL: https://www.sciencedirect.com/science/article/pii/B9780128020029000029
Skeletal Muscle
Clara Franzini-Armstrong, Andrew G. Engel, in Muscle, 2012
T-tubules Are Surface Invaginations; the SR Is an Internal Membrane System
T-tubules have a random, mostly longitudinal, disposition between the myofibrils during their initial formation but even at this stage they immediately form junctions with SR elements.