- 関
- large-conductance calcium-activated potassium channel
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"
- the 2nd letter of the Roman alphabet (同)b
- the blood group whose red cells carry the B antigen (同)type_B, group B
- official routes of communication; "you have to go through channels"
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
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/14 01:39:42」(JST)
[Wiki en表示]
| KCNMA1 |
|
The domain structure of BK channels
|
| Identifiers |
| Symbol |
KCNMA1 |
| Alt. symbols |
SLO |
| Entrez |
3778 |
| HUGO |
6284 |
| OMIM |
600150 |
| RefSeq |
NM_002247 |
| UniProt |
Q12791 |
| Other data |
| Locus |
Chr. 10 q22 |
| KCNMB1 |
| Identifiers |
| Symbol |
KCNMB1 |
| Entrez |
3779 |
| HUGO |
6285 |
| OMIM |
603951 |
| RefSeq |
NM_004137 |
| UniProt |
Q16558 |
| Other data |
| Locus |
Chr. 5 q34 |
| KCNMB2 |
| Identifiers |
| Symbol |
KCNMB2 |
| Entrez |
10242 |
| HUGO |
6286 |
| OMIM |
605214 |
| RefSeq |
NM_181361 |
| UniProt |
Q9Y691 |
| Other data |
| Locus |
Chr. 3 q26.32 |
| KCNMB3 |
| Identifiers |
| Symbol |
KCNMB3 |
| Alt. symbols |
KCNMB2, KCNMBL |
| Entrez |
27094 |
| HUGO |
6287 |
| OMIM |
605222 |
| RefSeq |
NM_171828 |
| UniProt |
Q9NPA1 |
| Other data |
| Locus |
Chr. 3 q26.3-q27 |
| KCNMB3L |
| Identifiers |
| Symbol |
KCNMB3L |
| Alt. symbols |
KCNMB2L, KCNMBLP |
| Entrez |
27093 |
| HUGO |
6288 |
| RefSeq |
NG_002679 |
| Other data |
| Locus |
Chr. 22 q11.1 |
| KCNMB4 |
| Identifiers |
| Symbol |
KCNMB4 |
| Entrez |
27345 |
| HUGO |
6289 |
| OMIM |
605223 |
| RefSeq |
NM_014505 |
| UniProt |
Q86W47 |
| Other data |
| Locus |
Chr. 12 q15 |
| Calcium-activated BK potassium channel alpha subunit |
| Identifiers |
| Symbol |
BK_channel_a |
| Pfam |
PF03493 |
| InterPro |
IPR003929 |
| Available protein structures: |
| Pfam |
structures |
| PDB |
RCSB PDB; PDBe; PDBj |
| PDBsum |
structure summary |
|
BK channels (Big Potassium), also called Maxi-K or slo1, are potassium channels characterized by their large conductance of potassium ions (K+) through cell membranes. These channels are activated (opened) by changes in membrane electrical potential and/or by increases in concentration of intracellular calcium ion (Ca2+).[1][2] Opening of BK channels allows K+ to passively flow through the channel, down the electrochemical gradient. Under typical physiological conditions, this results in an efflux of K+ from the cell, which leads to cell membrane hyperpolarization (an increase in the electrical potential across the cell membrane) and a decrease in cell excitability (a decrease in the probability that the cell will transmit an action potential).
BK channels are essential for the regulation of several key physiological processes including smooth muscle tone and neuronal excitability.[3] They control the contraction of smooth muscle and are involved with the electrical tuning of hair cells in the cochlea. BK channels also contribute to the behavioral effects of ethanol in the worm C. elegans under high exogenous doses (> 100 mM) [4] that have been shown to correspond to biologically relevant internal ethanol concentrations.[5] It remains to be determined if BK channels contribute to intoxication in humans.
Contents
- 1 Structure
- 2 Pharmacology
- 3 See also
- 4 References
- 5 External links
Structure
As with most other voltage-gated potassium channels, BK channels have a tetrameric structure. Each monomer of the channel-forming alpha subunit is the product of the KCNMA1 gene. Modulatory beta subunits (encoded by KCNMB1, KCNMB2, KCNMB3, or KCNMB4) can associate with the tetrametic channel.
BK channels are a prime example of modular protein evolution. Each BK channel alpha subunit consists of (from N- to C-terminal):
- A unique transmembrane domain (S0)[6] that precedes the 6 transmembrane domains (S1-S6) conserved in all voltage-dependent K+ channels.
- A voltage sensing domain (S1-S4).
- A K+ channel pore domain (S5, selectivity filter, and S6).
- A cytoplasmic C-terminal domain (CTD) consisting of a pair of RCK domains that assemble into an octameric gating ring on the intracellular side of the tetrameric channel.[7][8][9][10][11] The CTD contains four primary binding sites for Ca2+, called "calcium bowls", encoded within the second RCK domain of each monomer.[2][7][11][12]
Available X-ray structures:
- 3MT5 - Crystal Structure of the Human BK Gating Apparatus[2]
- 3NAF - Structure of the Intracellular Gating Ring from the Human High-conductance Ca2+ gated K+ Channel (BK Channel)[7]
- 3U6N - Open Structure of the BK channel Gating Ring[12]
Pharmacology
BK channels are pharmacological targets for the treatment of several medical disorders including stroke[13] and overactive bladder.[14] Although pharmaceutical companies have attempted to develop synthetic molecules targeting BK channels,[15] their efforts have proved largely ineffective. For instance, BMS-204352 (MaxiPost), a molecule developed by Bristol-Myers Squibb, failed to improve clinical outcome in stroke patients compared to placebo.[16] BK channels have also been found to be activated by exogenous pollutants and endogenous gazotransmitters carbon monoxide[17][18] and hydrogen sulphide.[19]
BK channels can be readily inhibited by a range of compounds including tetraethylammonium (TEA), paxilline[20] and iberiotoxin.[21]
See also
- Calcium-activated potassium channel subunit alpha-1
- Calcium-activated potassium channel
- Voltage-gated potassium channel
References
- ^ Miller C (2000). "An overview of the potassium channel family". Genome Biol. 1 (4): reviews0004.1–reviews0004.5. doi:10.1186/gb-2000-1-4-reviews0004. PMC 138870. PMID 11178249.
- ^ a b c Yuan P, Leonetti MD, Pico AR, Hsiung Y, MacKinnon R (July 2010). "Structure of the human BK channel Ca2+-activation apparatus at 3.0 A resolution". Science 329 (5988): 182–6. doi:10.1126/science.1190414. PMC 3022345. PMID 20508092.
- ^ EntrezGene 3778
- ^ Davies AG, Pierce-Shimomura JT, Kim H, VanHoven MK, Thiele TR, Bonci A, Bargmann CI, McIntire SL (December 2003). "A central role of the BK potassium channel in behavioral responses to ethanol in C. elegans". Cell 115 (6): 655–66. doi:10.1016/S0092-8674(03)00979-6. PMID 14675531.
- ^ Alaimo JT, Davis SJ, Song SS, Burnette CR, Grotewiel M, Shelton KL, Pierce-Shimomura JT, Davies AG, Bettinger JC. (April 2012). "Ethanol metabolism and osmolarity modify behavioral responses to ethanol in C. elegans". Alcohol Clin Exp Res 36 (11): 1840–50. doi:10.1111/j.1530-0277.2012.01799.x. PMID 22486589.
- ^ Wallner M, Meera P, Toro L (December 1996). "Determinant for beta-subunit regulation in high-conductance voltage-activated and Ca(2+)-sensitive K+ channels: an additional transmembrane region at the N terminus". Proc. Natl. Acad. Sci. U.S.A. 93 (25): 14922–7. doi:10.1073/pnas.93.25.14922. PMC 26238. PMID 8962157.
- ^ a b c Wu Y, Yang Y, Ye S, Jiang Y (July 2010). "Structure of the gating ring from the human large-conductance Ca(2+)-gated K(+) channel". Nature 466 (7304): 393–7. doi:10.1038/nature09252. PMC 2910425. PMID 20574420.
- ^ Jiang Y, Pico A, Cadene M, Chait BT, MacKinnon R (March 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. doi:10.1016/S0896-6273(01)00236-7. PMID 11301020.
- ^ Pico AR (2003). RCK domain model of calcium activation in BK channels (PhD thesis). New York: The Rockfeller University. hdl:10209/211.
- ^ Yusifov T, Savalli N, Gandhi CS, Ottolia M, Olcese R (January 2008). "The RCK2 domain of the human BKCa channel is a calcium sensor". Proc. Natl. Acad. Sci. U.S.A. 105 (1): 376–81. doi:10.1073/pnas.0705261105. PMC 2224220. PMID 18162557.
- ^ a b Schreiber M, Salkoff L (September 1997). "A novel calcium-sensing domain in the BK channel". Biophys. J. 73 (3): 1355–63. doi:10.1016/S0006-3495(97)78168-2. PMC 1181035. PMID 9284303.
- ^ a b Yuan P, Leonetti MD, Hsiung Y, MacKinnon R (January 2012). "Open structure of the Ca2+ gating ring in the high-conductance Ca2+-activated K+ channel". Nature 481 (7379): 94–7. doi:10.1038/nature10670. PMC 3319005. PMID 22139424.
- ^ Gribkoff VK, Starrett JE Jr, Dworetzky SI. (2001). "Maxi-K potassium channels: form, function, and modulation of a class of endogenous regulators of intracellular calcium.". Neuroscientist 2: 166–77. PMID 11496927.
- ^ Jeffrey J. Layne , Bernhard Nausch , Søren-Peter Olesen , Mark T. Nelso (2009). "BK channel activation by NS11021 decreases excitability and contractility of urinary bladder smooth muscle". American Journal of Physiology - Regulatory, Integrative and Comparative Physiology 298 (R378-R384). doi:10.1152/ajpregu.00458.2009. PMID 19923353.
- ^ Gribkoff VK, Winquist RJ (May 2005). "Voltage-gated cation channel modulators for the treatment of stroke". Expert Opin Investig Drugs 14 (5): 579–92. doi:10.1517/13543784.14.5.579. PMID 15926865.
- ^ Jensen BS (2002). "BMS-204352: a potassium channel opener developed for the treatment of stroke". CNS Drug Rev 8 (4): 353–60. doi:10.1111/j.1527-3458.2002.tb00233.x. PMID 12481191.
- ^ Dubuis E, Potier M, Wang R, Vandier C (February 2005). "Continuous inhalation of carbon monoxide attenuates hypoxic pulmonary hypertension development presumably through activation of BKCa channels". Cardiovasc. Res. 65 (3): 751–61. doi:10.1016/j.cardiores.2004.11.007. PMID 15664403.
- ^ Hou S, Xu R, Heinemann SH, Hoshi T (March 2008). "The RCK1 high-affinity Ca2+ sensor confers carbon monoxide sensitivity to Slo1 BK channels". Proc. Natl. Acad. Sci. U.S.A. 105 (10): 4039–43. doi:10.1073/pnas.0800304105. PMC 2268785. PMID 18316727.
- ^ Sitdikova GF, Weiger TM, Hermann A (February 2010). "Hydrogen sulfide increases calcium-activated potassium (BK) channel activity of rat pituitary tumor cells". Pflugers Arch. 459 (3): 389–97. doi:10.1007/s00424-009-0737-0. PMID 19802723.
- ^ "Paxilline, from Fermentek".
- ^ Candia S, Garcia ML, Latorre R (August 1992). "Mode of action of iberiotoxin, a potent blocker of the large conductance Ca(2+)-activated K+ channel". Biophys. J. 63 (2): 583–90. doi:10.1016/S0006-3495(92)81630-2. PMC 1262182. PMID 1384740.
External links
- BK 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.
|
Membrane transport protein: ion channels (TC 1A)
|
|
|
Ca2+: Calcium channel
|
|
| Ligand-gated |
- Inositol trisphosphate receptor
- Ryanodine receptor
|
|
| Voltage-gated |
- L-type/Cavα
- N-type/Cavα2.2
- P-type/Cavα
- Q-type/Cavα2.1
- R-type/Cavα2.3
- T-type/Cavα
- α2δ-subunits
- β-subunits
- γ-subunits
- Cation channels of sperm
- Two-pore channel
|
|
|
|
|
Na+: Sodium channel
|
|
| Constitutively active |
- Epithelial sodium channel
|
|
| Proton-gated |
- Amiloride-sensitive cation channel
|
|
| Voltage-gated |
- Navα
- 1.1
- 1.2
- 1.3
- 1.4
- 1.5
- 1.6
- 1.7
- 1.8
- 1.9
- 7A
- Navβ
|
|
|
|
|
K+: Potassium channel
|
|
| Calcium-activated |
- BK channel
- SK channel
- IK channel
- KCa
- 1.1
- 2.1
- 2.2
- 2.3
- 3.1
- 4.1
- 4.2
- 5.1
|
|
| Inward-rectifier |
|
|
| Tandem pore domain |
- K2P
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 9
- 10
- 12
- 13
- 15
- 16
- 17
- 18
|
|
| Voltage-gated |
- Kvα1-6
- 1.1
- 1.2
- 1.3
- 1.4
- 1.5
- 1.6
- 1.7
- 1.8
-
-
-
-
-
- Kvβ
- KCNIP
- minK/ISK
- minK/ISK-like
- MiRP
- Shaker gene
|
|
|
|
|
Miscellaneous
|
|
| Cl-: Chloride channel |
- Calcium-activated chloride channels
- Anoctamin
- Bestrophin
- Chloride Channel Accessory
- CFTR
- CLCN
- CLIC
- CLNS
|
|
| H+: Proton channel |
|
|
| M+: CNG cation channel |
|
|
| M+: TRP cation channel |
- TRPA (1)
- TRPC
- TRPM
- TRPML
- TRPN
- TRPP
- TRPV
|
|
| H2O (+ solutes): Porin |
- Aquaporin
- Voltage-dependent anion channel
- General bacterial porin family
|
|
| Cytoplasm: Gap junction |
- Connexin: A
- GJA1
- GJA3
- GJA4
- GJA5
- GJA8
- GJA9
- GJA10
- B
- GJB1
- GJB2
- GJB3
- GJB4
- GJB5
- GJB6
- GJB7
- C
- D
|
|
|
|
|
By gating mechanism
|
|
| Ion channel class |
- Ligand-gated
- Light-gated
- Voltage-gated
- Stretch-activated
|
|
|
|
|
see also disorders
B memb: cead, trns (1A, 1C, 1F, 2A, 3A1, 3A2-3, 3D), other
|
|
UpToDate Contents
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
English Journal
- Property of large conductance Ca(2+)-activated K(+) channels from Fasciola hepatica incorporated into planar lipid bilayer.
- Jang JH, Park JB, Kim SD, Lee SY, Hong SJ, Ryu PD.SourceDepartment of Pharmacology, Research Institute of Veterinary Science, College of Veterinary Medicine, Seoul National University, 599 Gwanank-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
- Veterinary parasitology.Vet Parasitol.2012 May 25;186(3-4):281-8. Epub 2011 Nov 20.
- Fasciola hepatica causes biliary epithelial hyperplasia and obstructive jaundice in humans and animals. Using a planar lipid bilayer technique, we further characterized the single channel property of large conductance K(+)-permeable channels that were previously identified from F. hepatica. The sing
- PMID 22154253
- The contribution of RCK domains to human BK channel allosteric activation.
- Savalli N, Pantazis A, Yusifov T, Sigg D, Olcese R.SourceUCLA - Anesthesiology, United States.
- The Journal of biological chemistry.J Biol Chem.2012 May 3. [Epub ahead of print]
- Large conductance voltage- and Ca2+-activated K+ (BK) channels are potent regulators of cellular processes including neuronal firing, synaptic transmission, cochlear hair cell tuning, insulin release and smooth muscle tone. Their unique activation pathway relies on structurally-distinct regulatory d
- PMID 22556415
Japanese Journal
- Upregulation of STREX splice variant of the large conductance Ca^<2+>-activated potassium (BK) channel in a rat model of mesial temporal lobe epilepsy
- ERMOLINSKY Boris S.,SKINNER Frank,GARCIA Ileana,ARSHADMANSAB Massoud F.,PACHECO OTALORA Luis F.,ZAREI Masoud M.,GARRIDO-SANABRIA Emilio R.
- Neuroscience research : the official journal of the Japan Neuroscience Society 69(1), 73-80, 2011-01-01
- NAID 10028190294
- Effect of Source/Drain Doping Gradient on Threshold Voltage Variation in Double-Gate Fin Field Effect Transistors as Determined by Discrete Random Doping
- Moon Dae-hyun,Song Jae-Joon,Kim Ohyun
- Jpn J Appl Phys 49(10), 104301-104301-4, 2010-10-25
- … We present a numerical simulation and physical analysis of how a single dopant in the channel region effects the variation of threshold voltage $\Delta V_{\text{th}}$ in highly scaled (gate length = 16 nm) and undoped double-gate fin field effect transistors. … The presence of a single contaminant dopant in an undoped channel with an abrupt source/drain (S/D) doping gradient can cause a severe change in $\Delta V_{\text{th}}$ (140 mV owing to a single acceptor; …
- NAID 150000053230
Related Links
- カリウムチャネル（英語：potassium channel）とは、細胞膜に存在するイオンチャネルの 一種である。ほとんどの細胞に存在し、カリウムイオンを選択的に ... BKチャネル（BK channel）; SKチャネル（SK channel）. 細胞内カルシウムを増加させる刺激後の抑制 ...
- BK channels (Big Potassium), also called Maxi-K or slo1, are ion channels characterized by their large conductance of potassium ions (K+) through cell membranes. These channels are activated (opened) by changes in membrane electrical ...
★リンクテーブル★
[★]
- 英
- large-conductance calcium-activated potassium channel、BK channel
- 関
- 大コンダクタンスカリウムチャネル、BKチャネル、大コンダクタンスカルシウム依存性カリウムチャネル
[★]
大コンダクタンスカルシウム活性化カリウムチャネル、大コンダクタンスカルシウム依存性カリウムチャネル
- 関
- BK channel
[★]
- 英
- BK channel
- 関
- BKチャネル、大コンダクタンスカルシウム活性化カリウムチャネル
[★]
- Mg2+存在下でC3, B, Dが反応してC3bBbとなり、これがC3転換酵素(C3bBb)あるいはC5転換酵素(C3bBb3b)を形成する。これらはP(properdin)と結合して活性化し、それぞれC3、C5を活性化する
[★]
- 川床、川底。水路、河道
- 海峡
- 水管、導管
- 溝
- 経路、ルート。道筋、方向
- 関
- ion channel、ionic channel
[★]