Channelpedia

Kv6.3

Description: potassium voltage-gated channel, subfamily G, member 3
Gene: Kcng3
Alias: Kv6.3, kcng3, kv10.1

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Introduction

Kv6.3, encoded by the gene KCNG3, is a member is a gamma subunit of the voltage-gated potassium channel, subfamily G. Kv6.3 is thought to be a delayed-rectifier type channels that may contribute to cardiac action potential repolarization. NCBI

Experimental data

Rat Kv6.3 gene in CHO host cells       datasheet

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15 °C
show 68 cells

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25 °C
show 61 cells

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35 °C
show 87 cells
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Gene

Species NCBI gene ID Chromosome Position
Human 170850 2 105630
Mouse 225030 17 58143
Rat 171011 6 47953
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Transcript

Species NCBI accession Length (nt)
Human NM_133329.6 3709
Mouse NM_153512.1 3356
Rat NM_133426.2 1586
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Protein Isoforms

Species Uniprot ID Length (aa)
Human Q8TAE7 436
Mouse P59053 433
Rat Q8R523 433

Isoforms

Transcript
Length (nt)
Protein
Length (aa)
Variant
Isoform
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Post-Translational Modifications

PTM
Position
Type
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Structure

Kv6.3
Visual Representation of Kv6.3 Structure
Methodology for visual representation of structure available here

Kv6.3 predicted AlphaFold size

Species Area (Å2) Reference
Human 5632.06 source
Mouse 5876.69 source
Rat 6243.30 source

Methodology for AlphaFold size prediction and disclaimer are available here

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Kinetics

Interaction of all Kv6.3 subunit on Kv2.1

Kv1.1 structure [664]

Whole-cell current recordings and subcellular localization of Kv2.1GFP, Kv6.3GFP and the coexpression Currents were evoked by stepping from −80 mV to +70 mV, 500 ms in duration, followed by a repolarizing pulse at −30 mV, 1 s in duration. Co-expression of Kv2.1 with Kv6.3GFP resulted in outward currents and green plasma membrane staining. This demonstrates that Kv2.1 was able to rescue the Kv6.3GFP subunits out of the ER [1708]

The profound effects of Kv6.3 on Kv2.1 gating properties suggest an important role for these heterotetramers: the latter would be inactivated at potentials close to resting potential (V½ for inactivation is −56 mV) in contrast to the homotetrameric Kv2.1 channels (V½ = −16 mV). Because both subunits are expressed in the brain functional heterotetramers could exist. Previous studies on the sustained delayed rectifier component of hippocampal neurons showed properties that are comparable with those of Kv2.1 and Kv6.3 heteromultimers. At −5 mV the two time constants for activation for the current in those neurons were 53 ms and 190 ms, which is comparable with heterotetrameric channels of Kv2.1 and Kv6.3 (Table 1). In addition, the midpoint of inactivation was more negative (−96 mV), which is at least closer to −56 mV for Kv2.1 and Kv6.3 compared with −16 mV for Kv2.1 alone [648]

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Function

Kv6.3 regulates Kv current amplitude and kinetics observed in vascular smooth muscle cells, suggesting that the remodelling of Kv2 current could be an important determinant of the hypertensive phenotype in resistance arteries. [662], [663]

The voltage-activated potassium channel subunits Kv2.1 and Kv2.2 are capable of heteromeric assembly with members of the Kv6 subfamily, which generates channels with different biophysical properties compared with homomeric Kv2.1 channels [661], [675], [676], [648], [398]. For the influence of Kv6.3 on Kv2.1, see [664].

In Kv6.x channels the histidine residue of the zinc ion-coordinating C3H1 motif of Kv2.1 is replaced by arginine or valine. Using a yeast two-hybrid assay, we found that substitution of the corresponding histidine 105 in Kv2.1 by valine (H105V) or arginine (H105R) disrupted the interaction of the T1 domain of Kv2.1 with the T1 domains of both Kv6.3 and Kv6.4, whereas interaction of the T1 domain of Kv2.1 with itself was unaffected by this mutation [664]

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Interaction

Kv2.1

The voltage-activated K(+) channel subunit Kv2.1 can form heterotetramers with members of the Kv6 subfamily, generating channels with biophysical properties different from homomeric Kv2.1 channels. The N-terminal tetramerization domain (T1) has been shown previously to play a role in Kv channel assembly [644]

References

496

Coetzee WA et al. Molecular diversity of K+ channels.
Ann. N. Y. Acad. Sci., 1999 Apr 30 , 868 (233-85).

638

Jan LY et al. Voltage-gated and inwardly rectifying potassium channels.
J. Physiol. (Lond.), 1997 Dec 1 , 505 ( Pt 2) (267-82).

648

Ottschytsch N et al. Obligatory heterotetramerization of three previously uncharacterized Kv channel alpha-subunits identified in the human genome.
Proc. Natl. Acad. Sci. U.S.A., 2002 Jun 11 , 99 (7986-91).

664

Mederos Y Schnitzler M et al. Mutation of histidine 105 in the T1 domain of the potassium channel Kv2.1 disrupts heteromerization with Kv6.3 and Kv6.4.
J. Biol. Chem., 2009 Feb 13 , 284 (4695-704).

665

Rudy B Diversity and ubiquity of K channels.
Neuroscience, 1988 Jun , 25 (729-49).

666

Hille B Ionic selectivity of Na and K channels of nerve membranes.
Membranes, 1975 , 3 (255-323).

667

Barry DM et al. Myocardial potassium channels: electrophysiological and molecular diversity.
Annu. Rev. Physiol., 1996 , 58 (363-94).

668

Deutsch C Potassium channel ontogeny.
Annu. Rev. Physiol., 2002 , 64 (19-46).

669

Robinson JM et al. Coupled tertiary folding and oligomerization of the T1 domain of Kv channels.
Neuron, 2005 Jan 20 , 45 (223-32).

670

Shen NV et al. Deletion analysis of K+ channel assembly.
Neuron, 1993 Jul , 11 (67-76).

671

Bixby KA et al. Zn2+-binding and molecular determinants of tetramerization in voltage-gated K+ channels.
Nat. Struct. Biol., 1999 Jan , 6 (38-43).

672

Jahng AW et al. Zinc mediates assembly of the T1 domain of the voltage-gated K channel 4.2.
J. Biol. Chem., 2002 Dec 6 , 277 (47885-90).

673

Strang C et al. The role of Zn2+ in Shal voltage-gated potassium channel formation.
J. Biol. Chem., 2003 Aug 15 , 278 (31361-71).

674

Tu L et al. Voltage-gated K+ channels contain multiple intersubunit association sites.
J. Biol. Chem., 1996 Aug 2 , 271 (18904-11).

675

Vega-Saenz de Miera EC Modification of Kv2.1 K+ currents by the silent Kv10 subunits.
Brain Res. Mol. Brain Res., 2004 Apr 7 , 123 (91-103).

1708

Ottschytsch N et al. Domain analysis of Kv6.3, an electrically silent channel.
J. Physiol. (Lond.), 2005 Nov 1 , 568 (737-47).

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Credits

Contributors: Rajnish Ranjan, Michael Schartner

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/wikipages/21/ , accessed on 2024 Apr 25


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