|
|
|
|
|
|
|
||
Article |
Address correspondence to Tom DeCoursey, Department of Molecular Biophysics and Physiology, Rush Presbyterian St. Luke's Medical Center, 1750 W Harrison, Chicago, IL 60612. Fax: (312) 942-8711; E-mail: tdecours{at}rush.edu
Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an enzyme of phagocytes that produces bactericidal superoxide anion (O2-) via an electrogenic process. Proton efflux compensates for the charge movement across the cell membrane. The proton channel responsible for the H+ efflux was thought to be contained within the gp91phox subunit of NADPH oxidase, but recent data do not support this idea (DeCoursey, T.E., V.V. Cherny, D. Morgan, B.Z. Katz, and M.C. Dinauer. 2001. J. Biol. Chem. 276:36063–36066). In this study, we investigated electrophysiological properties and superoxide production of COS-7 cells transfected with all NADPH oxidase components required for enzyme function (COSphox). The 7D5 antibody, which detects an extracellular epitope of the gp91phox protein, labeled 96–98% of COSphox cells. NADPH oxidase was functional because COSphox (but not COSWT) cells stimulated by phorbol myristate acetate (PMA) or arachidonic acid (AA) produced superoxide anion. No proton currents were detected in either wild-type COS-7 cells (COSWT) or COSphox cells studied at pHo 7.0 and pHi 5.5 or 7.0. Anion currents that decayed at voltages positive to 40 mV were the only currents observed. PMA or AA did not elicit detectable H+ current in COSWT or COSphox cells. Therefore, gp91phox does not function as a proton channel in unstimulated cells or in activated cells with a demonstrably functional oxidase.
Key Words: phagocytes • gp91phox • H+ channels • superoxide • respiratory burst
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  B. Musset, V. V. Cherny, D. Morgan, Y. Okamura, I. S. Ramsey, D. E. Clapham, and T. E. DeCoursey Detailed comparison of expressed and native voltage-gated proton channel currents J. Physiol., May 15, 2008; 586(10): 2477 - 2486. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Geiszt, K. Lekstrom, and T. L. Leto Analysis of mRNA Transcripts from the NAD(P)H Oxidase 1 (Nox1) Gene: EVIDENCE AGAINST PRODUCTION OF THE NADPH OXIDASE HOMOLOG-1 SHORT (NOH-1S) TRANSCRIPT VARIANT J. Biol. Chem., December 3, 2004; 279(49): 51661 - 51668. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. T. Quinn and K. A. Gauss Structure and regulation of the neutrophil respiratory burst oxidase: comparison with nonphagocyte oxidases J. Leukoc. Biol., October 1, 2004; 76(4): 760 - 781. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Schwarzer, T. E. Machen, B. Illek, and H. Fischer NADPH Oxidase-dependent Acid Production in Airway Epithelial Cells J. Biol. Chem., August 27, 2004; 279(35): 36454 - 36461. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. L. Petheo, A. Maturana, A. Spat, and N. Demaurex Interactions between Electron and Proton Currents in Excised Patches from Human Eosinophils J. Gen. Physiol., November 24, 2003; 122(6): 713 - 726. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. E. Decoursey Voltage-Gated Proton Channels and Other Proton Transfer Pathways Physiol Rev, April 1, 2003; 83(2): 475 - 579. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. M. Henderson and R. W. Meech Proton Conduction through gp91phox J. Gen. Physiol., November 25, 2002; 120(6): 759 - 765. [Full Text] [PDF]
|
|
|
|
|
|
N. Touret and S. Grinstein Voltage-gated Proton "Channels": a Spectator's Viewpoint J. Gen. Physiol., November 25, 2002; 120(6): 767 - 771. [Full Text] [PDF]
|
|
|
|
|
|
T. E. DeCoursey, D. Morgan, and V. V. Cherny The gp91phox Component of NADPH Oxidase Is Not a Voltage-gated Proton Channel J. Gen. Physiol., November 25, 2002; 120(6): 773 - 779. [Full Text] [PDF]
|
|
|
|
|
|
A. Maturana, K.-H. Krause, and N. Demaurex NOX Family NADPH Oxidases: Do They Have Built-in Proton Channels? J. Gen. Physiol., November 25, 2002; 120(6): 781 - 786. [Full Text] [PDF]
|
|
|
|
