Reference : Ca2+-dependent regulation of NOX2 activity via MRP proteins in HL-60 granulocytes
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/10993/5745
Ca2+-dependent regulation of NOX2 activity via MRP proteins in HL-60 granulocytes
English
Schenten, Véronique mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Bréchard, Sabrina mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Melchior, Chantal [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Plançon, Sébastien mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Salsmann, Alexandre mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
Tschirhart, Eric mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit >]
2008
Calcium Binding Proteins
Landes Bioscience
3
1
25-30
Yes (verified by ORBilu)
1554-8643
1554-8651
[en] calcium ; MRP-8/14 ; NOX2 ; H2O2 production ; HL-60 cells
[en] Recently, two proteins of the S100 protein family, the myeloid-related calcium-binding proteins MRP-8 and MRP-14 have been implicated in the Ca2+-induced activation of the neutrophil NADPH oxidase (NOX2) but the mechanism underlying this process remains unclear. In this study, the role of MRP-8/14 in the Ca2+-dependent regulation of NOX2 activity was characterized in neutrophil-like HL-60 cells using small interfering RNAs (siRNAs) to knock-down endogenous MRP-8 and/or MRP-14 expression. Real-time PCR and Western blot revealed that MRP-8 and MRP-14 expression was 20 times higher in dimethylsulfoxide-differentiated neutrophil-like HL-60 cells compared to quiescent HL-60 cells. Knock-down of MRP-8 and MRP-14 in differentiated HL-60 cells decreased protein levels by 30 and 45% respectively. The impact of the reduced MRP-8/14 protein expression on NOX2 activity was investigated by measuring fMLF-induced H2O2 production. In cells simultaneously transfected with MRP-8 and MRP14 siRNAs, H2O2 production was reduced by 50%, suggesting that both MRP-8 and MRP-14 are required for NOX2 activity; single knock-downs were inefficient. To elucidate the role of Ca2+ in MRP8/14, and consequently in NOX2 activation, siRNA-transfected cells were treated with the Ca2+ ionophore ionomycin prior to stimulation with PMA, a Ca2+-independent protein kinase C activator. PMA-induced H2O2 production was enhanced by ionomycin. This amplification of NOX2 activity was abolished by MRP8/14 knock-down, indicating that both MRP-8 and MRP-14 are necessary to regulate Ca2+-induced NOX2 activation. Taken together, our results suggest that the mechanism of MRPs activation is highly dependent on the increase of intracellular Ca2+ level for a full activation of NOX2.
http://hdl.handle.net/10993/5745
http://www.landesbioscience.com/journals/cbproteins/article/5067

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