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Identification of critical amino acids in the proximal C-terminal of TREK-2 K+ channel for activation by acidic pHi and ATP-dependent inhibition

Authors
 Joohan Woo  ;  Young Keul Jun  ;  Yin-Hua Zhang  ;  Joo Hyun Nam  ;  Dong Hoon Shin  ;  Sung Joon Kim 
Citation
 PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, Vol.470(2) : 327-337, 2018 
Journal Title
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY
ISSN
 0031-6768 
Issue Date
2018
MeSH
Adenosine Triphosphate/metabolism* ; Amino Acid Substitution ; HEK293 Cells ; Humans ; Hydrogen-Ion Concentration ; Phosphatidylinositol 4,5-Diphosphate/metabolism ; Potassium Channel Blockers/pharmacology ; Potassium Channels, Tandem Pore Domain/antagonists & inhibitors ; Potassium Channels, Tandem Pore Domain/chemistry* ; Potassium Channels, Tandem Pore Domain/genetics ; Potassium Channels, Tandem Pore Domain/metabolism ; Protein Domains
Keywords
ATP ; Intracellular pH ; PI(4,5)P2 ; TREK-2 ; Two-pore K+ channel
Abstract
TWIK-related two-pore domain K+ channels (TREKs) are regulated by intracellular pH (pHi) and Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). Previously, Glu306 in proximal C-terminal (pCt) of mouse TREK-1 was identified as the pHi-sensing residue. The direction of PI(4,5)P2 sensitivity is controversial, and we have recently shown that TREKs are inhibited by intracellular ATP via endogenous PI(4,5)P2 formation. Here we investigate the anionic and cationic residues of pCt for the pHi and ATP-sensitivity in human TREK-2 (hTREK-2). In inside-out patch clamp recordings (ITREK-2,i-o), acidic pHi-induced activation was absent in E332A and was partly attenuated in E335A. Neutralization of cationic Lys (K330A) also eliminated the acidic pHi sensitivity of ITREK-2,i-o. Unlike the inhibition of wild-type (WT) ITREK-2,i-o by intracellular ATP, neither E332A nor K330A was sensitive to ATP. Nevertheless, exogenous PI(4,5)P2 (10 μM) abolished ITREK-2 i-o in all the above mutants as well as in WT, indicating unspecific inhibition by exogenous PI(4,5)P2. In whole-cell recordings of TREK-2 (ITREK-2,w-c), K330A and E332A showed higher or fully active basal activity, showing attenuated or insignificant activation by 2-APB, arachidonic acid, or acidic pHe 6.9. ITREK-1,w-c of WT is largely suppressed by pHe 6.9, and the inhibition is slightly attenuated in K312A and E315A. The results show concerted roles of the oppositely charged Lys and Glu in pCt for the ATP-dependent low basal activity and pHi sensitivity.
Full Text
https://link.springer.com/article/10.1007%2Fs00424-017-2072-1
DOI
10.1007/s00424-017-2072-1
Appears in Collections:
1. College of Medicine (의과대학) > BioMedical Science Institute (의생명과학부) > 1. Journal Papers
Yonsei Authors
Shin, Dong Hoon(신동훈)
URI
https://ir.ymlib.yonsei.ac.kr/handle/22282913/167585
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