Channelpedia

Kcnab2

Description: potassium voltage-gated channel, shaker-related subfamily, beta member 2
Gene: Kcnab2     Synonyms: kcnab2

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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.


Experimental data


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Gene

RGD ID Chromosome Position Species
61828 5 169624099-169710725 Rat
62119 4 151764853-151851588 Mouse
1354203 1 6086380-6160523 Human

Kcnab2 : potassium voltage-gated channel, shaker-related subfamily, beta member 2


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Transcript

Acc No Sequence Length Source
NM_017304 n/A n/A NCBI
NM_010598 n/A n/A NCBI
NM_172130 n/A n/A NCBI
NM_003636 n/A n/A NCBI
NM_001199860 n/A n/A NCBI
NM_001199861 n/A n/A NCBI
NM_001199862 n/A n/A NCBI
NM_001199863 n/A n/A NCBI

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Ontology

Accession Name Definition Evidence
GO:0016021 integral to membrane Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane. IEA
GO:0005737 cytoplasm All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures. IEA

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Interaction


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Protein


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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].


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Distribution


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Expression

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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Functional

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].


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Kinetics


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Model


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

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).

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).

572

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


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Credits

Contributors: Rajnish Ranjan, Michael Schartner

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/ionchannels/146/ , accessed on [date]