Inhibition of ROMK potassium channel by syntaxin 1A

Tie-Jun Sun; Wei-Zhong Zeng; Chou-Long Huang

doi:10.1152/ajprenal.00320.2004

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Inhibition of ROMK potassium channel by syntaxin 1A

Journal article

Peer reviewed

Inhibition of ROMK potassium channel by syntaxin 1A

Tie-Jun Sun, Wei-Zhong Zeng and Chou-Long Huang

American journal of physiology. Renal physiology, Vol.288(2), pp.F284-289

02/2005

DOI: 10.1152/ajprenal.00320.2004

PMID: 15454395

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Abstract

ROMK potassium channels are present in the cortical collecting duct (CCD) of the kidney and serve as apical exit pathways for K+ secretion in this nephron segment. K+ secretion in the CCD is regulated by multiple factors. In this study, we show that syntaxin 1A, but not syntaxin 3 or 4, inhibited whole cell ROMK currents in Xenopus laevis oocytes. Syntaxin 1A, but not syntaxin 3 or 4, interacted with the COOH-terminal cytoplasmic domain of ROMK in intro. Coexpression with synaptobrevin 2 reversed inhibition of whole cell ROMK currents by syntaxin 1A. In excised inside-out membranes of oocytes, application of fusion proteins containing the cytoplasmic region of syntaxin 1A to the cytoplasmic face caused a dose-dependent inhibition of ROMK. We further examined regulation of the K+ channels in the CCD by syntaxin 1A. Application of botulinum toxin C1 to the excised inside-out membranes of the CCD caused an increase in the activity of K+ channels. In contrast, application of toxin B had no effects. These results suggest that syntaxin 1A causes a tonic inhibition of the K+ channels in the apical membrane of the CCD. Binding of synaptobrevin 2 to syntaxin 1A during docking and fusion of transport vesicles to the plasma membranes of CCD may lead to activation of these channels.

Animals

Antigens, Surface - pharmacology

Botulinum Toxins - pharmacology

Botulinum Toxins, Type A

Cell Membrane

Kidney Cortex - physiology

Membrane Proteins - pharmacology

Nerve Tissue Proteins - pharmacology

Oocytes

Potassium - pharmacokinetics

Potassium Channels - physiology

Potassium Channels, Inwardly Rectifying - physiology

R-SNARE Proteins

Syntaxin 1

Xenopus laevis

Details

Title: Subtitle: Inhibition of ROMK potassium channel by syntaxin 1A
Creators: Tie-Jun Sun - The University of Texas Southwestern Medical Center
Wei-Zhong Zeng - The University of Texas Southwestern Medical Center
Chou-Long Huang - Internal Medicine
Resource Type: Journal article
Publication Details: American journal of physiology. Renal physiology, Vol.288(2), pp.F284-289
DOI: 10.1152/ajprenal.00320.2004
PMID: 15454395
ISSN: 1931-857X
eISSN: 1522-1466
Grant note: DK-59530 / NIDDK NIH HHS DK-54368 / NIDDK NIH HHS
Language: English
Date published: 02/2005
Academic Unit: Nephrology; Internal Medicine
Record Identifier: 9984359886802771

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