HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/6/C1610    most recent 00461.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by O'Driscoll, K. E. Articles by Britton, F. C. Search for Related Content PubMed PubMed Citation Articles by O'Driscoll, K. E. Articles by Britton, F. C.

MEMBRANE TRANSPORTERS, ION CHANNELS, AND PUMPS

Expression, localization, and functional properties of Bestrophin 3 channel isolated from mouse heart

Departments of ¹Physiology and Cell Biology and ²Pharmacology, University of Nevada School of Medicine, Center of Biomedical Research Excellence, Reno, Nevada

Submitted 3 September 2008 ; accepted in final form 20 October 2008

Bestrophins are a novel family of proteins that encode calcium-activated chloride channels. In this study we establish that Bestrophin transcripts are expressed in the mouse and human heart. Native mBest3 protein expression and localization in heart was demonstrated by using a specific polyclonal mBest3 antibody. Immunostaining of isolated cardiac myocytes indicates that mBest3 is present at the membrane. Using the patch-clamp technique, we characterized the biophysical and pharmacological properties of mBest3 cloned from heart. Whole cell chloride currents were evoked in both HEK293 and COS-7 cells expressing mBest3 by elevation of intracellular calcium. mBest3 currents displayed a K_D for Ca²⁺ of 175 nM. The calcium-activated chloride current was found to be time and voltage independent and displayed slight outward rectification. The anion permeability sequence of the channel was SCN^–>I^–>Cl^–, and the current was inhibited by niflumic acid and DIDS in the micromolar range. In addition, we generated a site-specific mutation (F80L) in the putative pore region of mBest3 that significantly altered the ion conduction and pharmacology of this channel. Our functional and mutational studies examining the biophysical properties of mBest3 indicate that it functions as a pore-forming chloride channel that is activated by physiological levels of calcium. This study reports novel findings regarding the molecular expression, tissue localization, and functional properties of mBest3 cloned from heart.

calcium-activated chloride current; chloride channels; patch clamp; mutagenesis

This article has been cited by other articles:

				D. Duan Phenomics of cardiac chloride channels: the systematic study of chloride channel function in the heart J. Physiol., May 15, 2009; 587(10): 2163 - 2177. [Abstract] [Full Text] [PDF]