Channelpedia

KChip1

Description: Kv channel-interacting protein 1
Gene: Kcnip1     Synonyms: kchip1, kcnip1

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Introduction

KCNIP1 (also known as VABP; MGC95; KCHIP1) encodes a member of the family of voltage-gated potassium (Kv) channel-interacting proteins (KCNIPs), which belong to the recoverin branch of the EF-hand superfamily. Members of the KCNIP family are small calcium binding proteins. They all have EF-hand-like domains, and differ from each other in the N-terminus. They are integral subunit components of native Kv4 channel complexes. They may regulate A-type currents, and hence neuronal excitability, in response to changes in intracellular calcium. Alternative splicing results in multiple transcript variant encoding different isoforms.

http://www.ncbi.nlm.nih.gov/gene/30820


Experimental data


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Gene

RGD ID Chromosome Position Species
70886 10 18549984-18565789 Rat
736764 11 33529780-33743527 Mouse
732298 5 169780881-170163636 Human

Kcnip1 : Kv channel-interacting protein 1


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Transcript

Acc No Sequence Length Source
NM_022929 n/A n/A NCBI
NM_027398 n/A n/A NCBI
NM_001190885 n/A n/A NCBI
NM_001190886 n/A n/A NCBI
NM_001034837 n/A n/A NCBI
NM_014592 n/A n/A NCBI
NM_001034838 n/A n/A NCBI

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Ontology


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Interaction


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Protein


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Structure

The KCNIPs differ from other proteins in the family of neuronal calcium binding proteins because they contain a variable N-terminal sequence that shares no homology with other calcium-binding protein domains (reviewed in Borgoyne [1196]). The N-termini among the KCNIPs themselves are also unique and share no homology (An [1195]).


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Distribution


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Expression

KChIP1 is predominantly expressed in brain (An [1195]).

In the septum, lateral septal nuclei showed moderate and high signal for KCNIP1. KCNIP1 was expressed at high levels, in the reticular thalamic nuclei and medial habenular nuclei and were not expressed in most of the other thalamic nuclei. The olfactory system KCNIP1 was highly expressed in the granular layer. KCNIP1 mRNA was detected in the scattered neurons, most possibly interneurons, of all layers of the cerebral cortex. KCNIP1 was expressed at high levels in scattered neurons that are most likely interneurons, around the CA regions, the dentate gyrus, and the molecular layer. From fig 4 in Pruunsild [1194]

All three KChIPs co-localize and co-immunoprecipitate with brain Kv4 a-subunits, and are thus integral components of native Kv4 channel complexes. (An [1195])


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Functional

KChIPs (Kv-Channel-Interacting-Proteins) (An et al. 2000 [1195]) are related to known calcium-binding proteins, including frequenin, recoverin and calsenilin-DREAM (a transcriptional factor) (Pawlowski et al. 1996). KChIP1, KChIP2 and KChIP3 interact specifically with Kv4 channels in situ, upregulate current expression and modulate various aspects of inactivation gating (An et al. 2000 [1195]; Bähring et al. 2001b [1197]).

Inactivation of Kv4.1 and Kv4.3 channels expressed in Xenopus oocytes appears to happen by distinct methods when expressed alone, but when coexpressed with KChIP1, Kv4.1 and Kv4.3 currents are nearly indistinguishable. (Beck [25])

KChIP1 slows fast inactivation of Kv4.1 and Kv4.3 from the open state and facilitates closed-state inactivation. Additionally, KChIP1 favours inactivation from the preopen closed state by accelerating channel closing. (Beck [25])


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Kinetics

KChIPs slow rapid inactivation and accelerate recovery from inactivation. (Beck [25])


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Model


References

126

Van Hoorick D. et al. Differential modulation of Kv4 kinetics by KCHIP1 splice variants.
Mol. Cell. Neurosci., 2003 Oct , 24 (357-66).

1192

Liao YS. et al. Functional role of EF-hands 3 and 4 in membrane-binding of KChIP1.
J. Biosci., 2009 Jun , 34 (203-11).

1193

Pioletti M. et al. Three-dimensional structure of the KChIP1-Kv4.3 T1 complex reveals a cross-shaped octamer.
Nat. Struct. Mol. Biol., 2006 Nov , 13 (987-95).

Trimmer JS. et al. Modulation of A-type potassium channels by a family of calcium sensors.
Nature, 2000 Feb 3 , 403 (553-6).

Burgoyne RD. et al. The neuronal calcium sensor family of Ca2+-binding proteins.
Biochem. J., 2001 Jan 1 , 353 (1-12).


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