TABLE 9

KCa5.1 channels

Channel KCa 5.1
Description pH-sensitive large-conductance potassium channel
Other names Slo3, KCNMC1, Kcnma3
Molecular information Human: BC028701 (coding sequence not defined), chr. 8p11.2,7 KCNU1
Mouse: 1112aa, NM_008432, chr. 8
Rat: 1243aa, NM_031828, chr. 15p16
Associated subunits No β-subunits identified
Functional Assays Voltage- and patch-clamp
Current K+-selective (mouse Slo3)
Conductance 106pS with 160 mM symmetric K+ (mouse Slo3)2
Ion Selectivity PK+/PNa+ = 5.0 (mouse Slo3)2
Activation Gated by voltage and internal alkalization (half-maximal activation at pH 7.5)1,2,3,4,5,6
Inactivation None
Activators None
Blockers TEA, 50% block by 49 mM2
Gating inhibitors None
Radioligands None
Channel distribution Testis, spermatocytes2
Physiological functions Not established
Mutations and pathophysiology Not established
Pharmacological significance Not established
Comments No published functional expression data for the human ortholog
  • aa, amino acids; chr., chromosome; TEA, tetraethylammonium.

  • 1. Moss BL and Magleby KL (2001) Gating and conductance properties of BK channels are modulated by the S9-S10 tail domain of the alpha subunitA study of mSlo1 and mSlo3 wild-type and chimeric channels J Gen Physiol 118:711-734

  • 2. Schreiber M, Wei A, Yuan A, Gaut J, Saito M, and Salkoff L (1998) Slo3, a novel pH-sensitive K+ channel from mammalian spermatocytes. J Biol Chem 273:3509-3516

  • 3. Schreiber M, Yuan A, and Salkoff L (1999) Transplantable sites confer calcium sensitivity to BK channels. Nat Neurosci 2:416-421

  • 4. Shi J and Cui J (2001) Intracellular Mg2+ enhances the function of BK-type Ca2+-activated K+ channels. J Gen Physiol 118:589-606

  • 5. Shi J, Krishnamoorthy G, Yang Y, Hu L, Chaturvedi N, Harilal D, Qin J, and Cui J (2002) Mechanism of magnesium activation of calcium-activated potassium channels. Nature (Lond) 418:876-880

  • 6. Xia XM, Zhang X, and Lingle CJ (2004) Ligand-dependent activation of Slo family channels is defined by interchangeable cytosolic domains. J Neurosci 24:5585-5591

  • 7. GenBank accession no. AP000074