Structural determinants and specificities for ROMK1-phosphoinositide interaction

Wei-Zhong Zeng; Horng-Huei Liou; U Murali Krishna; J R Falck; Chou-Long Huang

doi:10.1152/ajprenal.00300.2001

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Structural determinants and specificities for ROMK1-phosphoinositide interaction

Journal article

Peer reviewed

Structural determinants and specificities for ROMK1-phosphoinositide interaction

Wei-Zhong Zeng, Horng-Huei Liou, U Murali Krishna, J R Falck and Chou-Long Huang

American journal of physiology. Renal physiology, Vol.282(5), pp.F826-834

05/2002

DOI: 10.1152/ajprenal.00300.2001

PMID: 11934692

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Abstract

We have recently reported that direct interaction between phosphatidylinositol bisphosphate (PIP(2)) and the COOH-terminal cytoplasmic domain of ROMK1 is important for opening of the channel. We identified arginine-188 of ROMK1 as a critical residue for this interaction. Here, we further report that substitution of a neutral amino acid for lysine-181, arginine-217, or lysine-218 decreases single-channel open probability for the full-conductance state and increases the frequency of opening at a subconductance state. Compared with wild-type ROMK1 channels, these substitution mutants also display an increased sensitivity to the block by anti-PIP(2) antibodies and to inhibition by intracellular protons. These results indicate that, like arginine-188, lysine-181, arginine-217, and lysine-218 are also involved in interactions with PIP(2) and are critical for ROMK1 to open at full conductance. Using synthetic phosphoinositides containing phosphates at different positions in the head group, we also examined the specificities of phosphoinositides in the regulation of ROMK1 channels. We found that phosphoinositides containing phosphate at both positions 4 and 5 of the inositol head group have the highest efficacy in activating ROMK1 channels. These results suggest that phosphatidylinositol 4,5-bisphosphate is likely the important phosphoinositide in the regulation of ROMK1 channels in a physiological membrane milieu.

Alanine

Amino Acid Sequence

Animals

Antibodies - pharmacology

Arginine

Binding Sites

Cattle

Electric Conductivity

Electrochemistry

Glutamine

Lysine

Molecular Sequence Data

Mutagenesis, Site-Directed

Oocytes - metabolism

Patch-Clamp Techniques

Phosphatidylinositol 4,5-Diphosphate - immunology

Phosphatidylinositol 4,5-Diphosphate - metabolism

Phosphatidylinositols - chemistry

Phosphatidylinositols - metabolism

Potassium Channels - chemistry

Potassium Channels - genetics

Potassium Channels - metabolism

Potassium Channels, Inwardly Rectifying

Structure-Activity Relationship

Transfection

Xenopus laevis

Details

Title: Subtitle: Structural determinants and specificities for ROMK1-phosphoinositide interaction
Creators: Wei-Zhong Zeng - The University of Texas Southwestern Medical Center
Horng-Huei Liou - Departments of Medicine and
U Murali Krishna - The University of Texas Southwestern Medical Center
J R Falck - The University of Texas Southwestern Medical Center
Chou-Long Huang - Departments of Medicine and
Resource Type: Journal article
Publication Details: American journal of physiology. Renal physiology, Vol.282(5), pp.F826-834
DOI: 10.1152/ajprenal.00300.2001
PMID: 11934692
ISSN: 1931-857X
eISSN: 1522-1466
Grant note: DK54368 / NIDDK NIH HHS GM-31278 / NIGMS NIH HHS
Language: English
Date published: 05/2002
Academic Unit: Nephrology; Internal Medicine
Record Identifier: 9984359860702771

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