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Kvβ2

Description: potassium voltage-gated channel, shaker-related subfamily, beta member 2
Gene: kcnab2
Alias: kcnab2, KvBeta2

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Introduction

This entry is about a potassium voltage-gated channel, shaker-related subfamily, beta member 2, also known as F5; I2rf5; Kcnb3.


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Gene

Species NCBI gene ID Chromosome Position
Human 8514 1 108504
Mouse 16498 4 86805
Rat 29738 5 88546

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Transcript

Species NCBI accession Length (nt)
Human NM_003636.4 3875
Mouse NM_001252656.2 3645
Rat NM_017304.2 1590

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Protein Isoforms

Species Uniprot ID Length (aa)
Human Q13303 367
Mouse P62482 367
Rat P62483 367

Isoforms

Transcript
Length (nt)
Protein
Length (aa)
Variant
Isoform

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Post-Translational Modifications

PTM
Position
Type

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Structure

It is not known whether the C termini of Kv channels assume a well defined 3D structure, but there is an increasing number of examples of the C-terminal domain of K+ channels assuming highly ordered structures, which play a fundamental role in channel function [625], [626]. Furthermore, Ju et al. [5] have proposed that the gating of the Kv2.1 channel is strongly influenced by specific interactions between the N- and C- terminal domains, suggesting they do assume a well defined 3D structure.

Auxiliary beta subunits bind to the alpha-subunit tetramer to form a heterooctameric complex [627], [628]. The binding occurs through the interaction of the Kv-beta C terminus with conserved loops in the Kv-alpha subunit N-terminal T1 domain [620].

Discussion of 3D structure of Shaker can be found in [304].

Kvβ2 predicted AlphaFold size

Species Area (Å2) Reference
Human 2205.65 source
Mouse 2315.80 source
Rat 2393.88 source

Methodology for AlphaFold size prediction and disclaimer are available here


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Expression and Distribution

Kvb expression is restricted to the spinal cord and dorsal root ganglia in the embryonic rat CNS. At birth, Kvb expression is detected in brainstem and midbrain nuclei, but not detected in the hippocampus, cerebellum or cerebral cortex. During the first postnatal week, Kvb expression is present in hippocampal and cortical pyramidal cells and in cerebellar Purkinje cells. Expression of Kvb subunits reaches adult levels by the third postnatal week in all of the brain regions examined. A rabbit antiserum directed against a unique peptide sequence in the N-terminus of the Kvb1 protein demonstrates that this subunit displays a novel expression pattern in the developing mouse brain. Kvb1 expression is high at birth in all brain regions examined and decreases with age. In contrast, Kvb2 expression is low at birth and increases with age to reach adult levels by the third postnatal week. [310]


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Function

It is known that in Shaker-like K+ channels, C termini are involved in a variety of processes that range from channel gating [621] [622] and voltage sensitivity [615] to the binding of the membrane-associated guanylate kinases [623]. They also participate in channel assembly in Kv 2.1 [624].

Kv-beta is known to modulate both the biosynthesis and the function of Kv channels. Coexpression of Kv-beta with Kv-alpha enhances channel synthesis and cell surface targeting [629], [630], [631].

Kvb2 (Kv-beta-2) accelerates a C-type inactivation of Kv1.4 channels [632] and the activation of Kv1.5 channels, and that it alters the activation threshold of Kv1.1 and Kv1.5 channels [633]. In vivo, Kvb2 can also indirectly modulate Kv channel inactivation by competing with other Kvb (Kvb1 or -3) for Kv-alpha-binding sites [634].


References

304

Sokolova O et al. Conformational changes in the C terminus of Shaker K+ channel bound to the rat Kvbeta2-subunit.
Proc. Natl. Acad. Sci. U.S.A., 2003 Oct 28 , 100 (12607-12).

310

Downen M et al. Developmental expression of voltage-gated potassium channel beta subunits.
Brain Res. Dev. Brain Res., 1999 Oct 20 , 117 (71-80).

311

312

572

Jan LY et al. Cloned potassium channels from eukaryotes and prokaryotes.
Annu. Rev. Neurosci., 1997 , 20 (91-123).

594

Hoshi T et al. Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
Science, 1990 Oct 26 , 250 (533-8).

614

Hille B Ionic channels: molecular pores of excitable membranes.
Harvey Lect., 1986-1987 , 82 (47-69).

616

Cushman SJ et al. Voltage dependent activation of potassium channels is coupled to T1 domain structure.
Nat. Struct. Biol., 2000 May , 7 (403-7).

618

Schulteis CT et al. Subunit folding and assembly steps are interspersed during Shaker potassium channel biogenesis.
J. Biol. Chem., 1998 Oct 2 , 273 (26210-7).

620

624

Bentley GN et al. Determinants of potassium channel assembly localised within the cytoplasmic C-terminal domain of Kv2.1.
Biochim. Biophys. Acta, 1999 Apr 14 , 1418 (176-84).

625

Jiang Y et al. Crystal structure and mechanism of a calcium-gated potassium channel.
Nature, 2002 May 30 , 417 (515-22).

627

Scott VE et al. Primary structure of a beta subunit of alpha-dendrotoxin-sensitive K+ channels from bovine brain.
Proc. Natl. Acad. Sci. U.S.A., 1994 Mar 1 , 91 (1637-41).

630

Nakahira K et al. Selective interaction of voltage-gated K+ channel beta-subunits with alpha-subunits.
J. Biol. Chem., 1996 Mar 22 , 271 (7084-9).

633

Heinemann SH et al. Functional characterization of Kv channel beta-subunits from rat brain.
J. Physiol. (Lond.), 1996 Jun 15 , 493 ( Pt 3) (625-33).

634


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Credits

Contributors: Rajnish Ranjan, Michael Schartner

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/wikipages/146/ , accessed on 2024 Dec 02



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