Rac-1-mediated O2- secretion requires Ca2+ influx in neutrophil-like HL-60 cells.
Neutrophil-like HL-60 cells reacted to N -formyl- l -Methionyl- l -Leucyl- l -P henylalanine (f MLP) with a rise in the intracellular calcium concentration ([Ca2]i), NADPH oxidase activation, and increased superoxide anion (O2-) production. [Ca2+]i mobilization and superoxide production were largely dependent on extracellular calcium (Ca2+]e) and a capacitative calcium entry. The monomeric G-protein, Rac-1, regulates NADPH oxidase activity. We tested the effect of removal of Ca2+]e on Rac-1 plasma membrane sequestration and activation of NADPH oxidase using immunodetection and a double labelling fluorescent method. Results showed that Rac-1 activation is mediated via a pertussis toxin (PTX)-sensitive heteromeric G-protein pathway, and that Rac-1 membrane sequestration was preceded by [Ca2+]i mobilization following entry of Ca2+ e. Therefore, we propose that O2- production is dependent on activation of PTX-sensitive G-proteins and sequestration of Rac-1 in the plasma membrane, following entry of Ca2+ e.
Valentin
F
F
Centre de Recherche Public-Santé, Laboratoire de Neuroimmunologie et Inflammation, L-1150 Luxembourg, Grand-Duché du Luxembourg.
Bueb
J
J
Capdeville-Atkinson
C
C
Tschirhart
E
E
D002118:Calcium / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D018922:HL-60 Cells / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000819:agonists; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism* / Q000494:pharmacology; D019255:NADPH Oxidases / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D020830:rac1 GTP-Binding Protein / Q000187:drug effects / Q000378:metabolism*
D007295:Inositol Phosphates; D017382:Reactive Oxygen Species; D010566:Virulence Factors, Bordetella; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein; D002118:Calcium