カルシウム活性化カリウムチャネル

WordNet

direct the flow of; "channel information towards a broad audience" (同)canalize, canalise
a television station and its programs; "a satellite TV channel"; "surfing through the channels"; "they offer more than one hundred channels" (同)television channel, TV channel
a passage for water (or other fluids) to flow through; "the fields were crossed with irrigation channels"; "gutters carried off the rainwater into a series of channels under the street"
(often plural) a means of communication or access; "it must go through official channels"; "lines of communication were set up between the two firms" (同)communication channel, line
a path over which electrical signals can pass; "a channel is typically what you rent from a telephone company" (同)transmission channel
a deep and relatively narrow body of water (as in a river or a harbor or a strait linking two larger bodies) that allows the best passage for vessels; "the ship went aground in the channel"
aerate (sewage) so as to favor the growth of organisms that decompose organic matter (同)aerate
make (substances) radioactive
make active or more active; "activate an old file"
make more adsorptive; "activate a metal"
rendered active; e.g. rendered radioactive or luminescent or photosensitive or conductive
(of e.g. a molecule) made reactive or more reactive (同)excited
(military) set up and placed on active assignment; "a newly activated unit"
(of sewage) treated with aeration and bacteria to aid decomposition
a light soft silver-white metallic element of the alkali metal group; oxidizes rapidly in air and reacts violently with water; is abundant in nature in combined forms occurring in sea water and in carnallite and kainite and sylvite (同)K, atomic number 19
a white metallic element that burns with a brilliant light; the fifth most abundant element in the earths crust; an important component of most plants and animals (同)Ca, atomic number 20

PrepTutorEJDIC

〈C〉『水路』(川・湾・運河の船の通行ができる深い部分) / 〈U〉河床・川底 / 〈C〉『海峡』 / 〈C〉みぞ(groove),(道路の)水渠(すいきょ) / 《複数形で》(運搬・伝達の)正式の経路(手続き);(一般に)経路 / 〈C〉(テレビ・ラジオの)チャンネル / …‘に'水路を開く / …‘に'みぞを堀る / …'を'伝える,流す
…'を'活動的にする / …‘に'放射能を与える / 〈物質〉'を'活性化する
ポタシウム,カリウム(金属元素;化学記号はK)
『カルシウム』(金属元素;化学記号は『Ca』)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/15 00:40:05」(JST)

wiki en

Calcium-activated potassium channels are potassium channels gated by calcium, or are structurally or phylogenetically related to calcium gated channels. In humans they are divided into BK channels, IK channels, and SK channels based on their conductance (big, intermediate, and small conductance).

This family of ion channels is, for the most part, activated by intracellular Ca²⁺ and contains 8 members in the human genome. However, some of these channels (the K_Ca4 and K_Ca5 channels) are responsive instead other intracellular ligands, such as Na⁺, Cl⁻, and pH. Furthermore, multiple members of family are both ligand and voltage activated, further complicating the description of this family. The K_Ca channel α subunits have six or seven transmembrane segments, similar to the K_V channels but occasionally with an additional N-terminal transmembrane helix. The α subunits make homo- and hetero-tetrameric complexes. The calcium binding domain may be contained in the α subunit sequence, as in K_Ca1, or may be through an additional calcium binding protein such as calmodulin.

Homology classification

Human K_Ca Channels

Below is a list of the 8 known human calcium-activated potassium channel grouped according to sequence homology of transmembrane hydrophobic cores:^[1]

BK channel

K_Ca1.1 (BK, Slo1, Maxi-K, KCNMA1)
- Beta subunits: β1, β2, β3, β4

SK channel

K_Ca2.1 (SK1, KCNN1)
K_Ca2.2 (SK2, KCNN2)
K_Ca2.3 (SK3, KCNN3)

IK channel

K_Ca3.1 (IKCa1, SK4, KCNN4)

Other subfamilies

K_Ca4.1 (Slack, Slo2.2, KCNT1)
K_Ca4.2 (Slick, Slo2.1, KCNT2)
K_Ca5.1 (Slo3, KCNU1)

Prokaryotic K_Ca Channels

A number of prokaryotic K_Ca channels have been described, both structurally and functionally. All are either gated by calcium or other ligands and are homologus to the human K_Ca channels, in particular the K_Ca1.1 gating ring. These structures have served as templates for ligand gating.

Protein	Species	Ligand	Function	Reference
Kch	Escherichia coli	Unknown	Channel	^[2]^[3]
MthK	Methanothermobacter thermautotrophicus	Calcium, Cadmium, Barium, pH	Channel	^[4]^[5]^[6]^[7]^[8]
TrkA/TrkH	Vibrio parahaemolyticus	ATP, ADP	Channel	^[9]^[10]
KtrAB	Bacillus subtilis	ATP, ADP	Transporter	^[11]
GsuK	Geobacter sulfurreducens	Calcium, ADP, NAD	Channel	^[12]
TM1088	Thermotoga maritima	Unknown	Unknown	^[13]

References

^ Wei AD, Gutman GA, Aldrich R, Chandy KG, Grissmer S, Wulff H (Dec 2005). "International Union of Pharmacology. LII. Nomenclature and molecular relationships of calcium-activated potassium channels". Pharmacological Reviews 57 (4): 463–72. doi:10.1124/pr.57.4.9. PMID 16382103.
^ Milkman R (Apr 1994). "An Escherichia coli homologue of eukaryotic potassium channel proteins". Proceedings of the National Academy of Sciences of the United States of America 91 (9): 3510–4. Bibcode:1994PNAS...91.3510M. doi:10.1073/pnas.91.9.3510. PMID 8170937.
^ Jiang Y, Pico A, Cadene M, Chait BT, MacKinnon R (Mar 2001). "Structure of the RCK domain from the E. coli K+ channel and demonstration of its presence in the human BK channel". Neuron 29 (3): 593–601. PMID 11301020.
^ Jiang Y, Lee A, Chen J, Cadene M, Chait BT, MacKinnon R (May 2002). "Crystal structure and mechanism of a calcium-gated potassium channel". Nature 417 (6888): 515–22. Bibcode:2002Natur.417..515J. doi:10.1038/417515a. PMID 12037559.
^ Smith FJ, Pau VP, Cingolani G, Rothberg BS (2013). "Structural basis of allosteric interactions among Ca2+-binding sites in a K+ channel RCK domain". Nature Communications 4: 2621. Bibcode:2013NatCo...4E2621S. doi:10.1038/ncomms3621. PMID 24126388.
^ Ye S, Li Y, Chen L, Jiang Y (Sep 2006). "Crystal structures of a ligand-free MthK gating ring: insights into the ligand gating mechanism of K+ channels". Cell 126 (6): 1161–73. doi:10.1016/j.cell.2006.08.029. PMID 16990139.
^ Dvir H, Valera E, Choe S (Aug 2010). "Structure of the MthK RCK in complex with cadmium". Journal of Structural Biology 171 (2): 231–7. doi:10.1016/j.jsb.2010.03.020. PMID 20371380.
^ Smith FJ, Pau VP, Cingolani G, Rothberg BS (Dec 2012). "Crystal structure of a Ba(2+)-bound gating ring reveals elementary steps in RCK domain activation". Structure 20 (12): 2038–47. doi:10.1016/j.str.2012.09.014. PMID 23085076.
^ Cao Y, Jin X, Huang H, Derebe MG, Levin EJ, Kabaleeswaran V, Pan Y, Punta M, Love J, Weng J, Quick M, Ye S, Kloss B, Bruni R, Martinez-Hackert E, Hendrickson WA, Rost B, Javitch JA, Rajashankar KR, Jiang Y, Zhou M (Mar 2011). "Crystal structure of a potassium ion transporter, TrkH". Nature 471 (7338): 336–40. Bibcode:2011Natur.471..336C. doi:10.1038/nature09731. PMC 3077569. PMID 21317882.
^ Cao Y, Pan Y, Huang H, Jin X, Levin EJ, Kloss B, Zhou M (Apr 2013). "Gating of the TrkH ion channel by its associated RCK protein TrkA". Nature 496 (7445): 317–22. Bibcode:2013Natur.496..317C. doi:10.1038/nature12056. PMC 3726529. PMID 23598339.
^ Vieira-Pires RS, Szollosi A, Morais-Cabral JH (Apr 2013). "The structure of the KtrAB potassium transporter". Nature 496 (7445): 323–8. Bibcode:2013Natur.496..323V. doi:10.1038/nature12055. PMID 23598340.
^ Kong C, Zeng W, Ye S, Chen L, Sauer DB, Lam Y, Derebe MG, Jiang Y (2012). "Distinct gating mechanisms revealed by the structures of a multi-ligand gated K(+) channel". eLife 1: e00184. doi:10.7554/eLife.00184. PMC 3510474. PMID 23240087.
^ Deller MC, Johnson HA, Miller MD, Spraggon G, Elsliger MA, Wilson IA, Lesley SA (2015). "Crystal Structure of a Two-Subunit TrkA Octameric Gating Ring Assembly". PloS One 10 (3): e0122512. Bibcode:2015PLoSO..1022512D. doi:10.1371/journal.pone.0122512. PMC 4380455. PMID 25826626.

External links

Calcium-Activated Potassium Channels at the US National Library of Medicine Medical Subject Headings (MeSH)
"Calcium-Activated Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.

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★リンクテーブル★

リンク元	「カルシウム活性化カリウムチャネル」
拡張検索	「large-conductance calcium-activated potassium channel」「intermediate-conductance calcium-activated potassium channel」「large-conductance calcium-activated potassium channel alpha subunit」「large-conductance calcium-activated potassium channel beta subunit」「small-conductance calcium-activated potassium channel」
関連記事	「channel」「activated」「activate」「calcium」