Activation gate

The first molecule, the Ca2+ channel, is required for coupling at the triad. Skeletal muscle contains higher concentrations of this L-type Ca2+ channel that can be accounted for on the basis of measured voltage-dependent Ca2+ influx because much of the Ca2+ channel protein in the T-tubular membrane does not actively gate calcium ion movement but, rather, acts as a voltage transducer that links depolarization of the T-tubular membrane to Ca2+ release through a receptor protein in the SR membrane. The ryanodine receptor mediates sarcoplasmic reticulum Ca2+ release. The bar-like structures that connect the terminal elements of the SR with the T-tubular membrane in the triad are formed by a large protein that is the principal pathway for Ca2+ release from the SR. This protein, which binds the... 

Mitcheson, J.S., Chen, J. and Sanguinetti, M.C. (2000) Trapping of a methanesulfonanilide by closure of the hERG potassium channel activation gate. The Journal of General Physiology, 115, 229-240. 

Chapter 5 Reference Number Year of Publication Chapter 5 and Reference Figure Numbers Activation Gate Open/ Closed... 

Fig. 1. Example of a receptor structure. Some anti-epileptic drugs interact with a receptor site on a Na" " channel and enhance the activity of the inactivation gate (I) decreasing the ahihty of neurons to fire at high frequencies. (A) indicates the activation gate of this ion channel. (Reprinted by permission from McNamara JO. Emerging insights into the genesis of epilepsy. Nature 1999 399(Suppl) A15-22, 1999 Macmillan Magazines Ltd.)...

A schematic representation of Na+ channels cycling through different conformational states during the cardiac action potential. Transitions between resting, activated, and inactivated states are dependent on membrane potential and time. The activation gate is shown as m and the inactivation gate as h. Potentials typical for each state are shown under each channel schematic as a function of time. The dashed line indicates that part of the action potential during which most Na+ channels are completely or partially inactivated and unavailable for reactivation. 

A further step in channel design must involve the introduction of (proton-, ion-, redox- or light-activated) gates and control elements for regulating opening and... 

Schmitt, J. M., Guire, E. S., Saneyoshi, T. and Soderling, T. R., 2005, Calmodulin-dependent kinase kinase/calmodulin kinase I activity gates extracellular-regulated kinase-dependent long-term potentiation, J Neurosci, 25, pp 1281-90. 

Armstrong, C. M. Bezanllla, F. Charge movement associated with the opening and closing of the activation gates of the Na channels. J. Gen. Physiol. 1974, 63, 533-552. 

Cortes, D., Cuello, L., and Perozo, E. (2001). Molecular architecture of full-length KcsA role of cytoplasmic domains in ion permeation and activation gating./ Gen. Physiol. 117, 165-180. 

Perozo, E., Cortes, D. M., and Cuello, L. G. (1999). Structural rearrangements underlying K+-channel activation gating. Science 285, 73-78. 

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