Channelpedia

Kv6.1

Description: potassium voltage-gated channel, subfamily G, member 1
Gene: Kcng1     Synonyms: Kv6.1, kcng1, kh2, kcng, k13

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Introduction

Heteromultimeric potassium channels may include alpha-subunits, such as Kv6.1, that are electrically silent when expressed alone, as is the case for the Kir2 subfamily [652], cyclic nucleotide gated channels [653], [654], [655] and perhaps the Kv4 subfamily [656].


Experimental data


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Gene

RGD ID Chromosome Position Species
631416 3 159427774-159447234 Rat
1614136 2 168087198-168094831 Mouse
1604067 20 49620193-49639675 Human

Kcng1 : potassium voltage-gated channel, subfamily G, member 1


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Transcript

Acc No Sequence Length Source
NM_001106545 n/A n/A NCBI
NM_001081134 n/A n/A NCBI
NM_002237 n/A n/A NCBI

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Ontology

Accession Name Definition Evidence
GO:0008076 voltage-gated potassium channel complex A protein complex that forms a transmembrane channel through which potassium ions may cross a cell membrane in response to changes in membrane potential. IEA
GO:0016020 membrane Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins. IEA

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Interaction


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Protein


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Structure

The sparsely populated Kv channel subfamilies Kv5 and Kv6 each contain one member, Kv5.1 and Kv6.1 (see Chandy, K.G. and Gutman, G.A. (1995) In: (R.A. North, ed.), Handbook of Receptors and Channels. Ligand- and Voltage- Gated Ion Channels. CRC Press, Ann Arbor, MI, pp. 1-71) referred to as IK8 and K13, [399]. No function has yet been demonstrated for either of these proteins alone [399]. Comparisons of predicted amino acid sequences strongly indicate that both Kv5.1 and Kv6.1 are members of the Kv family [399], exhibiting hallmarks such as the conserved GYGD sequence in H5 [657], six hydrophobic transmembrane domains including the positively charged S4 [658],[659], and amino terminal Tl [8] or NA and Nn [399],[660] domains.


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Distribution


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Expression

EXPRESSION OF KV6.1

Unlike kH1, 2.4 kb of kH2 was expressed predominantly in the brain, placenta, and the skeletal muscle where it shared a differently spliced form of the kH2 mRNA, approximately 2.0 kb [1698]

Expression in heart

All three known members of the Kv4 family are expressed in the ferret heart, with Kv4.2 being the most abundant (P≤.01). The transcript of Kv5.1 was most common in the right atrium (46.4%) and rarest in the atrial septum (21.5%). Kv6.1 was less abundant. It was present in 28.4% of SA nodal cells and in <16% of cells in the other anatomic regions [1774]


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Functional

Kv6.1 regulates the kinetics of Kv2.2 channels: It was much less effective in speeding inactivation at intermediate potentials than Kv5.1, had a slowing effect on inactivation at strong depolarizations, and had no effect on cumulative inactivation. Kv6.1 had profound effects on activation, including a negative shift of the steadystate activation curve and marked slowing of deactivation tail currents. [389]

Regulation of gating by electrically silent alpha-subunits, such as Kv6.1, is not restricted to the Kv2 subfamily. They interact with members of the Shal [651] and Kv3 (Shaw) [400] subfamilies as well.

Amino terminal portions of Kv6.1 were unable to form homomultimers but interacted specifically with amino termini of Kv2.1. Xenopus oocytes co-injected with Kv6.1 and Kv2.1 cRNAs exhibited a novel current with decreased rates of deactivation, decreased sensitivity to TEA block, and a hyperpolarizing shift of the half maximal activation potential when compared to Kv2.1. Our results indicate that Kv channel subfamilies can form heteromultimeric channels and, for the first time, suggest a possible functional role for the Kv6 subfamily.


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Kinetics

KV6.1 Kinetics with Kv2

Kv5.1 kin

We previously showed that coexpression of Kv2.1 and Kv6.1 resulted in currents that deactivated extremely slowly upon depolarization [398]



Human Kv6.1/ Kv6.3/ Kv6.4 Expressed with human Kv2.1 in CHO-K1 Cells

Kv5.1 kin Currents were measured using whole cells patch clamp techniques. The cells were superfused with symmetrical high K+ solutions and depolarizing voltage steps were applied from the holding potential of -80 mV to potentials between -70 and +40 mV (10 mV increments)


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Model


References

651

Salkoff L. et al. A novel subunit for shal K+ channels radically alters activation and inactivation.
J. Neurosci., 1997 Jan 1 , 17 (32-44).

400

Lazdunski M. et al. New modulatory alpha subunits for mammalian Shab K+ channels.
J. Biol. Chem., 1997 Sep 26 , 272 (24371-9).

652

Gonoi T. et al. Kir2.2v: a possible negative regulator of the inwardly rectifying K+ channel Kir2.2.
FEBS Lett., 1996 May 20 , 386 (211-4).

653

Chen TY. et al. A new subunit of the cyclic nucleotide-gated cation channel in retinal rods.
Nature, 1993 Apr 22 , 362 (764-7).

655

Davidson N. et al. Heteromeric olfactory cyclic nucleotide-gated channels: a subunit that confers increased sensitivity to cAMP.
Proc. Natl. Acad. Sci. U.S.A., 1994 Sep 13 , 91 (8890-4).

659

Liman ER. et al. Voltage-sensing residues in the S4 region of a mammalian K+ channel.
Nature, 1991 Oct 24 , 353 (752-6).


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Credits

Editor : Admin.

Contributors : Rajnish Ranjan, Michael Schartner

To cite : [Editor], [Contributors]. Accessed on [Date] Channelpedia , http://channelpedia.epfl.ch/ionchannels/19