L-type calcium channel
| Calcium channel, voltage-dependent | |
|---|---|
 Crystallographic structure | |
| Identifiers | |
| Symbol | Calcium channel, voltage-dependent |
Immunohistochemical analysis of L-type calcium channel Cav1.3 (CACNA1D) in human adrenal cortex. Marked immunoreactivity was detected in the zona glomerulosa. In the figure: ZG = zona glomerulosa, ZF = zona fasciculata, AC = adrenal capsule. Immunohistochemistry was performed according to published methods.[1]
The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel.[2]
"L" stands for long-lasting referring to the length of activation. This channel has four subunits (Cav1.1, Cav1.2, Cav1.3, Cav1.4).
L-type calcium channels are responsible for the excitation-contraction coupling of skeletal, smooth, cardiac muscle, and for aldosterone secretion in endocrine cells of the adrenal cortex.[1]
In cardiac myocytes, the L-type calcium channel passes inward Ca2+ current and triggers calcium release from the sarcoplasmic reticulum by activating ryanodine receptor 2 (RyR2) (calcium-induced-calcium-release).[3] Phosphorylation of these channels increases their permeability to calcium and increases the contractility of their respective cardiac myocytes.
L-type calcium channel blocker drugs are used as cardiac antiarrhythmics or antihypertensives, depending on whether the drugs have higher affinity for the heart (the phenylalkylamines, like verapamil), or for the vessels (the dihydropyridines, like nifedipine).
In skeletal muscle, there is a very high concentration of L-type calcium channels, situated in
the T-tubules. Muscle depolarization results in large gating
currents, but anomalously low calcium flux, which is now
explained by the very slow activation of the ionic currents. For
this reason, little or no Ca2+ passes across the T-tubule
membrane during a single action potential.
Contents
1 Structure
2 Genes
3 See also
4 References
5 External links
Structure
Like most voltage-gated ion channels, the α-subunit is composed of 4 subunits. Each subunit is formed by 6 alpha-helical, transmembrane domains that cross the membrane (numbered S1-S6). The S1-S4 subunits make up the voltage sensor, while S5-S6 subunits make up the selectivity filter.[4]
Alpha subunit of a generic voltage-gated ion channel
Genes
CACNA1C, CACNA1D, CACNA1S, CACNA1F
See also
- CACNA1C
- CACNA1D
- CACNA1S
- CACNA1F
References
^ ab Felizola SJ, Maekawa T, Nakamura Y, Satoh F, Ono Y, Kikuchi K, Aritomi S, Ikeda K, Yoshimura M, Tojo K, Sasano H (2014). "Voltage-gated calcium channels in the human adrenal and primary aldosteronism". J Steroid Biochem Mol Biol. 144 (part B): 410–416. doi:10.1016/j.jsbmb.2014.08.012. PMID 25151951..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ Rossier, Michel F. (2016). "T-Type Calcium Channel: A Privileged Gate for Calcium Entry and Control of Adrenal Steroidogenesis". Frontiers in Endocrinology. 7. doi:10.3389/fendo.2016.00043. ISSN 1664-2392.
^ Yamakage M, Namiki A (February 2002). "Calcium channels--basic aspects of their structure, function and gene encoding; anesthetic action on the channels--a review". Canadian Journal of Anaesthesia = Journal Canadien D'anesthesie. 49 (2): 151–64. doi:10.1007/BF03020488. PMID 11823393.
^ Catterall, William A.; Perez-Reyes, Edward; Snutch, Terrance P.; Striessnig, Joerg (December 2005). "International Union of Pharmacology. XLVIII. Nomenclature and Structure-Function Relationships of Voltage-Gated Calcium Channels". Pharmacol Rev. 57 (4): 411–425. doi:10.1124/pr.57.4.5. PMID 16382099. Retrieved 30 November 2014.
External links
"Voltage-Gated Calcium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.
L-Type+Calcium+Channel at the US National Library of Medicine Medical Subject Headings (MeSH)
