Non-basic amino acids in the ROMK1 channels via an appropriate distance modulate PIP2 regulated pHi-gating

Chien-Hsing Lee; Po-Tsang Huang; Horng-Huei Liou; Mei-Ying Lin; Kuo-Long Lou; Chung-Yi Chen

doi:10.1016/j.bbrc.2016.03.100

Non-basic amino acids in the ROMK1 channels via an appropriate distance modulate PIP2 regulated pHi-gating

Biochem Biophys Res Commun. 2016 Apr 22;473(1):303-310. doi: 10.1016/j.bbrc.2016.03.100. Epub 2016 Mar 22.

Authors

Chien-Hsing Lee¹, Po-Tsang Huang², Horng-Huei Liou³, Mei-Ying Lin⁴, Kuo-Long Lou⁵, Chung-Yi Chen⁶

Affiliations

¹ Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan; Department of Nursing, Min-Hwei Junior College of Health Care Management, Tainan, 73658, Taiwan.
² Institutes of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan; Graduate Institutes of Oral Biology, Medical College, National Taiwan University, Taipei, 10048, Taiwan.
³ Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan; Divisions of Neurology, National Taiwan University Hospital, Taipei, 10002, Taiwan.
⁴ Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, 80708, Taiwan.
⁵ Institutes of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan; Graduate Institutes of Oral Biology, Medical College, National Taiwan University, Taipei, 10048, Taiwan; NTU-DRCP Lectures and Core for Membrane Proteins, Center for Biotechnology, National Taiwan University, Taipei, 10672, Taiwan. Electronic address: kllou@ntu.edu.tw.
⁶ School of Medical and Health Sciences, Fooyin University, No.151, Jinxue Rd., Daliao Dist., Kaohsiung City, 83102, Taiwan. Electronic address: xx377@fy.edu.tw.

PMID: 27016482
DOI: 10.1016/j.bbrc.2016.03.100

Abstract

The ROMK1 (Kir1.1) channel activity is predominantly regulated by intracellular pH (pHi) and phosphatidylinositol 4,5-bisphosphate (PIP2). Although several residues were reported to be involved in the regulation of pHi associated with PIP2 interaction, the detailed molecular mechanism remains unclear. We perform experiments in ROMK1 pHi-gating with electrophysiology combined with mutational and structural analysis. In the present study, non basic residues of C-terminal region (S219, N215, I192, L216 and L220) in ROMK1 channels have been found to mediate channel-PIP2 interaction and pHi gating. Further, our structural results show these residues with an appropriate distance to interact with membrane PIP2. Meanwhile, a cluster of basic residues (R188, R217 and K218), which was previously discovered regarding the interaction with PIP2, exists in this appropriate distance to discriminate the regulation of channel-PIP2 interaction and pHi-gating. This appropriate distance can be observed with high conservation in the Kir channel family. Our results provide insight that an appropriate distance cooperates with the electrostatics interaction of channel-PIP2 to regulate pHi-gating.

Keywords: Electrophysiology; Intracellular pH (pH(i)); Phosphatidylinositol 4,5-bisphosphate (PIP(2)); ROMK1 (Kir1.1) channel; Structural analysis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algorithms
Amino Acid Sequence
Animals
Chickens
Electrophysiology
Female
Humans
Hydrogen-Ion Concentration
Mice
Molecular Docking Simulation
Molecular Dynamics Simulation
Molecular Sequence Data
Mutation
Oocytes / metabolism
Phosphatidylinositol 4,5-Diphosphate / chemistry*
Potassium Channels, Inwardly Rectifying / metabolism
Potassium Channels, Inwardly Rectifying / physiology*
Protein Structure, Tertiary
Sequence Homology, Amino Acid
Static Electricity
Xenopus laevis

Substances

Phosphatidylinositol 4,5-Diphosphate
Potassium Channels, Inwardly Rectifying