Voltage-gated calcium channel
Two-pore channel | |||||||||
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Identifiers | |||||||||
Symbol | TPC | ||||||||
Pfam | PF08473 | ||||||||
OPM superfamily | 8 | ||||||||
OPM protein | 6c96 | ||||||||
Membranome | 214 | ||||||||
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Voltage-gated calcium channels (VGCCs), also known as voltage-dependent calcium channels (VDCCs), are a group of voltage-gated ion channels found in the membrane of excitable cells (e.g., muscle, glial cells, neurons, etc.) with a permeability to the calcium ion Ca2+.[1][2] These channels are slightly permeable to sodium ions, so they are also called Ca2+–Na+ channels, but their permeability to calcium is about 1000-fold greater than to sodium under normal physiological conditions.[3]
At physiologic or resting membrane potential, VGCCs are normally closed. They are activated (i.e.: opened) at depolarized membrane potentials and this is the source of the "voltage-gated" epithet. The concentration of calcium (Ca2+ ions) is normally several thousand times higher outside the cell than inside. Activation of particular VGCCs allows a Ca2+ influx into the cell, which, depending on the cell type, results in activation of calcium-sensitive potassium channels, muscular contraction,[4] excitation of neurons, up-regulation of gene expression, or release of hormones or neurotransmitters.
VGCCs have been immunolocalized in the zona glomerulosa of normal and hyperplastic human adrenal, as well as in aldosterone-producing adenomas (APA), and in the latter T-type VGCCs correlated with plasma aldosterone levels of patients.[5] Excessive activation of VGCCs is a major component of excitotoxicity, as severely elevated levels of intracellular calcium activates enzymes which, at high enough levels, can degrade essential cellular structures.
Structure
[edit]Voltage-gated calcium channels are formed as a complex of several different subunits:
Channel subunits
[edit]There are several different kinds of high-voltage-gated calcium channels (HVGCCs). They are structurally homologous among varying types; they are all similar, but not structurally identical. In the laboratory, it is possible to tell them apart by studying their physiological roles and/or inhibition by specific toxins. High-voltage-gated calcium channels include the neural N-type channel blocked by
Current type | 1,4-dihydropyridine sensitivity (DHP) | ||
---|---|---|---|
L-type | blocks | resistant | resistant |
N-type | resistant | blocks | resistant |
P/Q-type | resistant | resistant | blocks |
R-type | resistant | resistant | resistant |
Reference for the table can be found at Dunlap, Luebke and Turner (1995).[7]
α 1 Subunit
[edit]The
Type | Voltage | Associated subunits | Most often found in | |
---|---|---|---|---|
L-type calcium channel ("Long-Lasting" AKA "DHP Receptor") | HVA (high voltage activated) | Cav1.1 (CACNA1S) Cav1.2 (CACNA1C) Cav1.3 (CACNA1D) Cav1.4 (CACNA1F) |
Skeletal muscle, smooth muscle, bone (osteoblasts), ventricular myocytes** (responsible for prolonged action potential in cardiac cell; also termed DHP receptors), dendrites and dendritic spines of cortical neurones | |
P-type calcium channel ("Purkinje") /Q-type calcium channel | HVA (high voltage activated) | Cav2.1 (CACNA1A) | Purkinje neurons in the cerebellum / Cerebellar granule cells | |
N-type calcium channel ("Neural"/"Non-L") | HVA (high voltage activated) | Cav2.2 (CACNA1B) | Throughout the brain and peripheral nervous system. | |
R-type calcium channel ("Residual") | intermediate voltage activated | Cav2.3 (CACNA1E) | Cerebellar granule cells, other neurons | |
T-type calcium channel ("Transient") | low voltage activated | Cav3.1 (CACNA1G) Cav3.2 (CACNA1H) Cav3.3 (CACNA1I) |
neurons, cells that have pacemaker activity, bone (osteocytes) |
α 2δ Subunit
[edit]The
Co-expression of the
The
β Subunit
[edit]The intracellular
It is hypothesized that the cytosolic
In addition to this trafficking role, the
Until very recently, the interaction between a highly conserved 18-amino acid region on the
γ Subunit
[edit]The
There are 8 genes for gamma subunits:
Muscle physiology
[edit]When a smooth muscle cell is depolarized, it causes opening of the voltage-gated (L-type) calcium channels.[13][14] Depolarization may be brought about by stretching of the cell, agonist-binding its G protein-coupled receptor (GPCR), or autonomic nervous system stimulation. Opening of the L-type calcium channel causes influx of extracellular Ca2+, which then binds calmodulin. The activated calmodulin molecule activates myosin light-chain kinase (MLCK), which phosphorylates the myosin in thick filaments. Phosphorylated myosin is able to form crossbridges with actin thin filaments, and the smooth muscle fiber (i.e., cell) contracts via the sliding filament mechanism. (See reference[13] for an illustration of the signaling cascade involving L-type calcium channels in smooth muscle).
L-type calcium channels are also enriched in the t-tubules of striated muscle cells, i.e., skeletal and cardiac myofibers. When these cells are depolarized, the L-type calcium channels open as in smooth muscle. In skeletal muscle, the actual opening of the channel, which is mechanically gated to a calcium-release channel (a.k.a. ryanodine receptor, or RYR) in the sarcoplasmic reticulum (SR), causes opening of the RYR. In cardiac muscle, opening of the L-type calcium channel permits influx of calcium into the cell. The calcium binds to the calcium release channels (RYRs) in the SR, opening them; this phenomenon is called "calcium-induced calcium release", or CICR. However the RYRs are opened, either through mechanical-gating or CICR, Ca2+ is released from the SR and is able to bind to troponin C on the actin filaments. The muscles then contract through the sliding filament mechanism, causing shortening of sarcomeres and muscle contraction.
Changes in expression during development
[edit]Early in development, there is a high amount of expression of T-type calcium channels. During maturation of the nervous system, the expression of N or L-type currents becomes more prominent.[15] As a result, mature neurons express more calcium channels that will only be activated when the cell is significantly depolarized. The different expression levels of low-voltage activated (LVA) and high-voltage activated (HVA) channels can also play an important role in neuronal differentiation. In developing Xenopus spinal neurons LVA calcium channels carry a spontaneous calcium transient that may be necessary for the neuron to adopt a GABAergic phenotype as well as process outgrowth.[16]
Clinical significance
[edit]Voltage-gated calcium channels antibodies are associated with Lambert-Eaton myasthenic syndrome and have also been implicated in paraneoplastic cerebellar degeneration.[17]
Voltage-gated calcium channels are also associated with malignant hyperthermia[18] and Timothy syndrome.[19]
Mutations of the CACNA1C gene, with a single-nucleotide polymorphism in the third intron of the Cav1.2 gene,[20] are associated with a variant of long QT syndrome called Timothy's syndrome[21] and also with Brugada syndrome.[22] Large-scale genetic analyses have shown the possibility that CACNA1C is associated with bipolar disorder[23] and subsequently also with schizophrenia.[24][25][26] Also, a CACNA1C risk allele has been associated to a disruption in brain connectivity in patients with bipolar disorder, while not or only to a minor degree, in their unaffected relatives or healthy controls.[27]
See also
[edit]References
[edit]- ^ a b Catterall WA, Perez-Reyes E, Snutch TP, Striessnig J (December 2005). "International Union of Pharmacology. XLVIII. Nomenclature and structure-function relationships of voltage-gated calcium channels". Pharmacological Reviews. 57 (4): 411–25. doi:10.1124/pr.57.4.5. PMID 16382099. S2CID 10386627.
- ^ 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. 49 (2): 151–64. doi:10.1007/BF03020488. PMID 11823393.
- ^ Hall JE (2011). Guyton and Hall Textbook of Medical Physiology with Student Consult Online Access (PDF) (12th ed.). Philadelphia: Elsevier Saunders. p. 64. ISBN 978-1-4160-4574-8. Archived from the original (PDF) on 2011-05-16. Retrieved 2011-03-22.
- ^ Wilson DP, Susnjar M, Kiss E, Sutherland C, Walsh MP (August 2005). "Thromboxane A2-induced contraction of rat caudal arterial smooth muscle involves activation of Ca2+ entry and Ca2+ sensitization: Rho-associated kinase-mediated phosphorylation of MYPT1 at Thr-855, but not Thr-697". The Biochemical Journal. 389 (Pt 3): 763–74. doi:10.1042/BJ20050237. PMC 1180727. PMID 15823093.
- ^ Felizola SJ, Maekawa T, Nakamura Y, Satoh F, Ono Y, Kikuchi K, Aritomi S, Ikeda K, Yoshimura M, Tojo K, Sasano H (October 2014). "Voltage-gated calcium channels in the human adrenal and primary aldosteronism". The Journal of Steroid Biochemistry and Molecular Biology. 144 Pt B (part B): 410–6. doi:10.1016/j.jsbmb.2014.08.012. PMID 25151951. S2CID 23622821.
- ^ Dolphin AC (January 2006). "A short history of voltage-gated calcium channels". British Journal of Pharmacology. 147 (Suppl 1): S56-62. doi:10.1038/sj.bjp.0706442. PMC 1760727. PMID 16402121.
- ^ Dunlap K, Luebke JI, Turner TJ (February 1995). "Exocytotic Ca2+ channels in mammalian central neurons". Trends in Neurosciences. 18 (2): 89–98. doi:10.1016/0166-2236(95)93882-X. PMID 7537420.
- ^ Zakon HH (June 2012). "Adaptive evolution of voltage-gated sodium channels: the first 800 million years" (PDF). Proceedings of the National Academy of Sciences of the United States of America. 109 (Suppl 1): 10619–25. Bibcode:2012PNAS..10910619Z. doi:10.1073/pnas.1201884109. PMC 3386883. PMID 22723361.
- ^ Tombola F, Pathak MM, Isacoff EY (1 November 2006). "How does voltage open an ion channel?". Annual Review of Cell and Developmental Biology. 22 (1): 23–52. doi:10.1146/annurev.cellbio.21.020404.145837. PMID 16704338.
- ^ Cens T, Rousset M, Leyris JP, Fesquet P, Charnet P (Jan–Apr 2006). "Voltage- and calcium-dependent inactivation in high voltage-gated Ca(2+) channels". Progress in Biophysics and Molecular Biology. 90 (1–3): 104–17. doi:10.1016/j.pbiomolbio.2005.05.013. PMID 16038964.
- ^ Zvejniece L, Vavers E, Svalbe B, Veinberg G, Rizhanova K, Liepins V, Kalvinsh I, Dambrova M (October 2015). "R-phenibut binds to the
α 2-δ subunit of voltage-dependent calcium channels and exerts gabapentin-like anti-nociceptive effects". Pharmacology Biochemistry and Behavior. 137: 23–9. doi:10.1016/j.pbb.2015.07.014. PMID 26234470. S2CID 42606053. - ^ Bichet D, Cornet V, Geib S, Carlier E, Volsen S, Hoshi T, Mori Y, De Waard M (January 2000). "The I-II loop of the Ca2+ channel alpha1 subunit contains an endoplasmic reticulum retention signal antagonized by the beta subunit". Neuron. 25 (1): 177–90. doi:10.1016/S0896-6273(00)80881-8. PMID 10707982.
- ^ a b Webb RC (December 2003). "Smooth muscle contraction and relaxation". Advances in Physiology Education. 27 (1–4): 201–6. doi:10.1152/advan.00025.2003. PMID 14627618. S2CID 14267377.
- ^ Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2002). Molecular Biology of the Cell (4th ed.). New York, NY: Garland Science. p. 1616. ISBN 0-8153-3218-1.
- ^ Sanes DH, Reh TA (2012). Development of the nervous system (Third ed.). Elsevier Academic Press. pp. 211–214. ISBN 9780080923208. OCLC 762720374.
- ^ Rosenberg SS, Spitzer NC (October 2011). "Calcium signaling in neuronal development". Cold Spring Harbor Perspectives in Biology. 3 (10): a004259. doi:10.1101/cshperspect.a004259. PMC 3179332. PMID 21730044.
- ^ Bekircan-Kurt CE, Derle Çiftçi E, Kurne AT, Anlar B (March 2015). "Voltage gated calcium channel antibody-related neurological diseases". World Journal of Clinical Cases. 3 (3): 293–300. doi:10.12998/wjcc.v3.i3.293. PMC 4360501. PMID 25789302.
- ^ Monnier N, Procaccio V, Stieglitz P, Lunardi J (June 1997). "Malignant-hyperthermia susceptibility is associated with a mutation of the alpha 1-subunit of the human dihydropyridine-sensitive L-type voltage-dependent calcium-channel receptor in skeletal muscle". American Journal of Human Genetics. 60 (6): 1316–25. doi:10.1086/515454. PMC 1716149. PMID 9199552.
- ^ Splawski I, Timothy K, Sharpe L, Decher N, Kumar P, Bloise R, Napolitano C, Schwartz P, Joseph R, Condouris K, Tager-Flusberg H, Priori S, Sanguinetti M, Keating M (2004). "Ca(V)1.2 calcium channel dysfunction causes a multisystem disorder including arrhythmia and autism". Cell. 119 (1): 19–31. doi:10.1016/j.cell.2004.09.011. PMID 15454078.
- ^ Imbrici P, Camerino DC, Tricarico D (2013-05-07). "Major channels involved in neuropsychiatric disorders and therapeutic perspectives". Frontiers in Genetics. 4: 76. doi:10.3389/fgene.2013.00076. PMC 3646240. PMID 23675382.
- ^ Pagon RA, Bird TC, Dolan CR, Stephens K, Splawski I, Timothy KW, Priori SG, Napolitano C, Bloise R (1993). "Timothy Syndrome". PMID 20301577.
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(help)[clarification needed] - ^ Hedley PL, Jørgensen P, Schlamowitz S, Moolman-Smook J, Kanters JK, Corfield VA, Christiansen M (Sep 2009). "The genetic basis of Brugada syndrome: a mutation update". Human Mutation. 30 (9): 1256–66. doi:10.1002/humu.21066. PMID 19606473.
- ^ Ferreira MA, O'Donovan MC, Meng YA, Jones IR, Ruderfer DM, Jones L, et al. (Sep 2008). "Collaborative genome-wide association analysis supports a role for ANK3 and CACNA1C in bipolar disorder". Nature Genetics. 40 (9): 1056–8. doi:10.1038/ng.209. PMC 2703780. PMID 18711365.
- "Channeling Mental Illness: GWAS Links Ion Channels, Bipolar Disorder". Schizophrenia Research Forum. Archived from the original on 2010-12-18.
- ^ Green EK, Grozeva D, Jones I, Jones L, Kirov G, Caesar S, Gordon-Smith K, Fraser C, Forty L, Russell E, Hamshere ML, Moskvina V, Nikolov I, Farmer A, McGuffin P, Holmans PA, Owen MJ, O'Donovan MC, Craddock N (Oct 2010). "The bipolar disorder risk allele at CACNA1C also confers risk of recurrent major depression and of schizophrenia". Molecular Psychiatry. 15 (10): 1016–22. doi:10.1038/mp.2009.49. PMC 3011210. PMID 19621016.
- ^ Curtis D, Vine AE, McQuillin A, Bass NJ, Pereira A, Kandaswamy R, Lawrence J, Anjorin A, Choudhury K, Datta SR, Puri V, Krasucki R, Pimm J, Thirumalai S, Quested D, Gurling HM (Feb 2011). "Case-case genome-wide association analysis shows markers differentially associated with schizophrenia and bipolar disorder and implicates calcium channel genes". Psychiatric Genetics. 21 (1): 1–4. doi:10.1097/YPG.0b013e3283413382. PMC 3024533. PMID 21057379.
- ^ Schizophrenia Working Group of the Psychiatric Genomics Consortium (2014-07-24). "Biological insights from 108 schizophrenia-associated genetic loci". Nature. 511 (7510): 421–427. Bibcode:2014Natur.511..421S. doi:10.1038/nature13595. ISSN 1476-4687. PMC 4112379. PMID 25056061.
- ^ Radua J, Surguladze SA, Marshall N, Walshe M, Bramon E, Collier DA, Prata DP, Murray RM, McDonald C (May 2013). "The impact of CACNA1C allelic variation on effective connectivity during emotional processing in bipolar disorder". Molecular Psychiatry. 18 (5): 526–7. doi:10.1038/mp.2012.61. PMID 22614292.
External links
[edit]- "Voltage-Gated Ion Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.
- Calcium+Channels at the U.S. National Library of Medicine Medical Subject Headings (MeSH)