Small conductance (SK) calcium-activated potassium channels are a type of Ca2+-activated K+ channels. SK channels, apparently voltage insensitive, are gated by submicromolar-levels of intracellular Ca2+ ions and are important for regulating afterhyperpolarization in central neurones and other cell types.
Additional recommended knowledge
SK channels are thought to be involved in synaptic plasticity and can be pharmacologically blocked by a plant-derived neurotoxin Bicuculline
The SK channel family contains 3 members - Sk1, SK2 and SK3.
All cloned SK channels, SK1, SK2 and SK3 are sensitive to the bee venom apamin and the scorpion venom tamapin.
Several SK channel family subunits were cloned (See for example Dr. John Adelman http://www.ohsu.edu/vollum/faculty/adelman/
Classification
- Kca2.x : Kca2.1 (KCNN1), Kca2.2 (KCNN2), Kca2.3 (KCNN3)
- Kca3.x: Kca3.1 (KCNN4)
- Kca4.x: Kca4.1 (KCNT1), Kca4.2 (KCNT2)
Membrane transport protein: ion channels |
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Ca2+: Calcium channel | Voltage-dependent calcium channel (L-type/Cavα(1.1, 1.2, 1.3, 1.4), N-type, P-type/Cavα(2.1), Q-type, R-type, T-type, β-subunits (β1, β2, β4), γ-subunits (γ2) • Inositol triphosphate receptor • Ryanodine receptor • Cation channels of sperm • Two-pore channel |
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Na+: Sodium channel | Navα (1.1, 1.2, 1.4, 1.5, 1.7, 1.9) • Navβ (1, 3, 4) • Epithelial sodium channel |
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K+: Potassium channel | Voltage-gated (Kvα (1.1, 1.2, 1.3, 1.4, 1.5, 2.1, 4.2, 4.3, 7.1, 7.2, 7.3, 7.4, 10.1, 11.1/hERG) • Kvβ (1, 2), Shaker gene, KCNE1) • Calcium-activated (BK channel, SK channel, SK3) • Inward-rectifier Kir (1.1, 2.1, 2.2, 2.3, 3.1, 3.2, 3.4, 4.1, 4.2, 6.1, 6.2)) • Tandem pore domain K2P (1, 2, 3, 4, 6, 9) |
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Cl-: Chloride channel | Cystic fibrosis transmembrane conductance regulator |
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Porin | Aquaporin (1, 2, 3, 4) • Voltage-dependent anion channel (1) |
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Cations: TRP | TRPA (1) • TRPC (1, 2, 3, 4, 4AP, 5, 6, 7) • TRPM (1, 2, 3, 4, 5, 6, 7, 8) • TRPML (Mucolipin-1) • TRPP (1, 2)• TRPV (1, 2, 3, 4, 5, 6) |
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Other/general | Voltage-gated ion channel • Ligand-gated ion channel • Cyclic nucleotide-gated ion channel (α1, α3, β3, H1, H2, H4) • Stretch-activated ion channel |
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