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Title

Chemoattractant-induced respiratory burst: increases in cytosolic Ca2+ concentrations are essential and synergize with a kinetically distinct second signal

Authors
Petersson, F.
Published in Biochemical Journal. 1997, vol. 322 ( Pt 3), p. 709-718
Abstract The role of the cytosolic free Ca2+ concentration ([Ca2+]c) and its relationship to other second messengers in the signalling between chemoattractant [e.g. N-formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP)] receptors and the NADPH oxidase is still poorly understood. In this study, we have used thapsigargin, an inhibitor of the Ca2+-ATPase of intracellular stores, as a tool to selectively manipulate Ca2+ release from intracellular stores and Ca2+ influx across the plasma membrane. We thereby temporarily separated the Ca2+ signal from other signals generated by fMLP and analysed the consequences on the respiratory burst. Under all conditions investigated, the extent of fMLP-induced respiratory burst activation was critically determined by [Ca2+]c elevation. fMLP was unable to activate the respiratory burst without [Ca2+]c elevation. Thapsigargin-induced Ca2+ influx activated the respiratory burst in the absence of fMLP, but only to approx. 20% of the values observed in the presence of fMLP. The second signal generated by fMLP did not activate the respiratory burst by itself, but acted in synergy with [Ca2+]c elevation. The second signal was long lasting (>15 min) provided that there was no rise in [Ca2+]c and that the receptor was continuously occupied. The second signal was inactivated by high [Ca2+]c elevation. Our results demonstrate that [Ca2+]c elevations are an essential step in the signalling between the fMLP receptor and NADPH oxidase. They also provide novel information about the properties of the second Ca2+-independent signal that activates the respiratory burst in synergy with [Ca2+]c.
Keywords Calcium/ metabolismChemotactic Factors/ pharmacologyHL-60 CellsHumansRespiratory Burst/ drug effectsSecond Messenger SystemsSignal Transduction
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PMID: 9148740
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Other version: http://www.biochemj.org/bj/322/0709/3220709.pdf
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FOYOUZI-YOUSSEFI, Reyhaneh et al. Chemoattractant-induced respiratory burst: increases in cytosolic Ca2+ concentrations are essential and synergize with a kinetically distinct second signal. In: Biochemical Journal, 1997, vol. 322 ( Pt 3), p. 709-718. https://archive-ouverte.unige.ch/unige:7223

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Deposited on : 2010-06-21

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