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Kv6.1

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

Introductions


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].

Genes


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

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

Transcripts


Acc No Sequence Length Source
NM_001106545 NCBI
NM_001081134 NCBI
NM_002237 NCBI

Ontologies


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

Interactions


Proteins


Structures


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.

Distributions


Expressions


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]

Functionals


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.

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)

Models


References


[649 : 2112229]
[312 : 8183366]
[651 : 8987734]
[400 : 9305895]
[652 : 8647284]
[653 : 7682292]
[654 : 7522482]
[655 : 7522325]
[656 : 8626431]
[657 : 15277578]
[658 : 1846229]
[659 : 1944534]
[660 : 7559593]
[399 : 8980147]
[398 : 9696692]
[1774 : 8635239]

Credits


Editor : Admin.

Contributors : Rajnish Ranjan, Michael Schartner

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