title: Non-basic amino acids in the ROMK1 channels via an appropriate distance modulate PIP2 regulated pHi-gating.
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.
authors.affiliation: 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.
authors.forename: Chien-Hsing
authors.initials: CH
authors.lastname: Lee
authors.affiliation: 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.
authors.forename: Po-Tsang
authors.initials: PT
authors.lastname: Huang
authors.affiliation: Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, 10051, Taiwan; Divisions of Neurology, National Taiwan University Hospital, Taipei, 10002, Taiwan.
authors.forename: Horng-Huei
authors.initials: HH
authors.lastname: Liou
authors.affiliation: Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, 80708, Taiwan.
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Lin
authors.affiliation: 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.
authors.forename: Kuo-Long
authors.initials: KL
authors.lastname: Lou
authors.affiliation: School of Medical and Health Sciences, Fooyin University, No.151, Jinxue Rd., Daliao Dist., Kaohsiung City, 83102, Taiwan. Electronic address: xx377@fy.edu.tw.
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D004594:Electrophysiology; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D051379:Mice; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000737:chemistry*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D014982:Xenopus laevis
chemical_list: D019269:Phosphatidylinositol 4,5-Diphosphate; D024661:Potassium Channels, Inwardly Rectifying
keywords: Electrophysiology; Intracellular pH (pH(i)); Phosphatidylinositol 4,5-bisphosphate (PIP(2)); ROMK1 (Kir1.1) channel; Structural analysis