The LQLP calcineurin docking site is a major determinant of the calcium-dependent activation of human TRESK background K+ channel

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Calcium-dependent activation of human TRESK (TWIK-related spinal cord K+ channel, K2P18.1) depends on direct targeting of calcineurin to the PQIIIS motif. In the present study we demonstrate that TRESK also contains another functionally relevant docking site for the phosphatase, the LQLP amino acid sequence. Combined mutations of the PQIIIS and LQLP motifs were required to eliminate the calcium-dependent regulation of the channel. In contrast to the alanine substitutions of PQIIIS, the mutation of LQLP to AQAP alone did not significantly change the amplitude of TRESK activation evoked by the substantial elevation of cytoplasmic calcium concentration. However, the AQAP mutation slowed down the response to high calcium. In addition, modest elevation of [Ca2+], which effectively regulated the wild type channel, failed to activate TRESK-AQAP. This indicates that the AQAP mutation diminished the sensitivity of TRESK to calcium. Even if PQIIIS was replaced by the PVIVIT sequence of high calcineurin binding affinity, the effect of the AQAP mutation was clearly detected in this TRESK-PVIVIT context. Substitution of the LQLP region with the corresponding fragment of NFAT transcription factor, perfectly matching the previously described LXVP calcineurinbinding consensus sequence, increased the calcium-sensitivity of TRESK-PVIVIT. Thus the enhancement of the affinity of TRESK for calcineurin by the incorporation of PVIVIT could not compensate for or prevent the effects of LQLP sequence modifications, suggesting that the two calcineurin-binding regions play distinct roles in the regulation. Our results indicate that the LQLP site is a fundamental determinant of the calciumsensitivity of human TRESK.

Original languageEnglish
Pages (from-to)29506-29518
Number of pages13
JournalJournal of Biological Chemistry
Volume289
Issue number43
DOIs
Publication statusPublished - Oct 24 2014

Fingerprint

Calcineurin
Chemical activation
Calcium
Mutation
Substitution reactions
Consensus Sequence
Phosphoric Monoester Hydrolases
Alanine
Amino Acid Sequence
Spinal Cord
Transcription Factors
Amino Acids

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology
  • Medicine(all)

Cite this

@article{93910272e3b1438c9afbf59c09a9fe2c,
title = "The LQLP calcineurin docking site is a major determinant of the calcium-dependent activation of human TRESK background K+ channel",
abstract = "Calcium-dependent activation of human TRESK (TWIK-related spinal cord K+ channel, K2P18.1) depends on direct targeting of calcineurin to the PQIIIS motif. In the present study we demonstrate that TRESK also contains another functionally relevant docking site for the phosphatase, the LQLP amino acid sequence. Combined mutations of the PQIIIS and LQLP motifs were required to eliminate the calcium-dependent regulation of the channel. In contrast to the alanine substitutions of PQIIIS, the mutation of LQLP to AQAP alone did not significantly change the amplitude of TRESK activation evoked by the substantial elevation of cytoplasmic calcium concentration. However, the AQAP mutation slowed down the response to high calcium. In addition, modest elevation of [Ca2+], which effectively regulated the wild type channel, failed to activate TRESK-AQAP. This indicates that the AQAP mutation diminished the sensitivity of TRESK to calcium. Even if PQIIIS was replaced by the PVIVIT sequence of high calcineurin binding affinity, the effect of the AQAP mutation was clearly detected in this TRESK-PVIVIT context. Substitution of the LQLP region with the corresponding fragment of NFAT transcription factor, perfectly matching the previously described LXVP calcineurinbinding consensus sequence, increased the calcium-sensitivity of TRESK-PVIVIT. Thus the enhancement of the affinity of TRESK for calcineurin by the incorporation of PVIVIT could not compensate for or prevent the effects of LQLP sequence modifications, suggesting that the two calcineurin-binding regions play distinct roles in the regulation. Our results indicate that the LQLP site is a fundamental determinant of the calciumsensitivity of human TRESK.",
author = "G. Czirj{\'a}k and P. Enyedi",
year = "2014",
month = "10",
day = "24",
doi = "10.1074/jbc.M114.577684",
language = "English",
volume = "289",
pages = "29506--29518",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "43",

}

TY - JOUR

T1 - The LQLP calcineurin docking site is a major determinant of the calcium-dependent activation of human TRESK background K+ channel

AU - Czirják, G.

AU - Enyedi, P.

PY - 2014/10/24

Y1 - 2014/10/24

N2 - Calcium-dependent activation of human TRESK (TWIK-related spinal cord K+ channel, K2P18.1) depends on direct targeting of calcineurin to the PQIIIS motif. In the present study we demonstrate that TRESK also contains another functionally relevant docking site for the phosphatase, the LQLP amino acid sequence. Combined mutations of the PQIIIS and LQLP motifs were required to eliminate the calcium-dependent regulation of the channel. In contrast to the alanine substitutions of PQIIIS, the mutation of LQLP to AQAP alone did not significantly change the amplitude of TRESK activation evoked by the substantial elevation of cytoplasmic calcium concentration. However, the AQAP mutation slowed down the response to high calcium. In addition, modest elevation of [Ca2+], which effectively regulated the wild type channel, failed to activate TRESK-AQAP. This indicates that the AQAP mutation diminished the sensitivity of TRESK to calcium. Even if PQIIIS was replaced by the PVIVIT sequence of high calcineurin binding affinity, the effect of the AQAP mutation was clearly detected in this TRESK-PVIVIT context. Substitution of the LQLP region with the corresponding fragment of NFAT transcription factor, perfectly matching the previously described LXVP calcineurinbinding consensus sequence, increased the calcium-sensitivity of TRESK-PVIVIT. Thus the enhancement of the affinity of TRESK for calcineurin by the incorporation of PVIVIT could not compensate for or prevent the effects of LQLP sequence modifications, suggesting that the two calcineurin-binding regions play distinct roles in the regulation. Our results indicate that the LQLP site is a fundamental determinant of the calciumsensitivity of human TRESK.

AB - Calcium-dependent activation of human TRESK (TWIK-related spinal cord K+ channel, K2P18.1) depends on direct targeting of calcineurin to the PQIIIS motif. In the present study we demonstrate that TRESK also contains another functionally relevant docking site for the phosphatase, the LQLP amino acid sequence. Combined mutations of the PQIIIS and LQLP motifs were required to eliminate the calcium-dependent regulation of the channel. In contrast to the alanine substitutions of PQIIIS, the mutation of LQLP to AQAP alone did not significantly change the amplitude of TRESK activation evoked by the substantial elevation of cytoplasmic calcium concentration. However, the AQAP mutation slowed down the response to high calcium. In addition, modest elevation of [Ca2+], which effectively regulated the wild type channel, failed to activate TRESK-AQAP. This indicates that the AQAP mutation diminished the sensitivity of TRESK to calcium. Even if PQIIIS was replaced by the PVIVIT sequence of high calcineurin binding affinity, the effect of the AQAP mutation was clearly detected in this TRESK-PVIVIT context. Substitution of the LQLP region with the corresponding fragment of NFAT transcription factor, perfectly matching the previously described LXVP calcineurinbinding consensus sequence, increased the calcium-sensitivity of TRESK-PVIVIT. Thus the enhancement of the affinity of TRESK for calcineurin by the incorporation of PVIVIT could not compensate for or prevent the effects of LQLP sequence modifications, suggesting that the two calcineurin-binding regions play distinct roles in the regulation. Our results indicate that the LQLP site is a fundamental determinant of the calciumsensitivity of human TRESK.

UR - http://www.scopus.com/inward/record.url?scp=84908199248&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84908199248&partnerID=8YFLogxK

U2 - 10.1074/jbc.M114.577684

DO - 10.1074/jbc.M114.577684

M3 - Article

C2 - 25202008

AN - SCOPUS:84908199248

VL - 289

SP - 29506

EP - 29518

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 43

ER -