Aerolysin induces G-protein activation and Ca2+ release from intracellular stores in human granulocytes

Krause, Karl-Heinz; Fivaz, M.; Monod, Antoinette; van der Goot, F. G.

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Title		Aerolysin induces G-protein activation and Ca2+ release from intracellular stores in human granulocytes
Authors		Krause, Karl-Heinz Fivaz, M. Monod, Antoinette van der Goot, F. G.
Published in		Journal of Biological Chemistry. 1998, vol. 273, no. 29, p. 18122-18129
Abstract		Aerolysin is a pore-forming toxin that plays a key role in the pathogenesis of Aeromonas hydrophila infections. In this study, we have analyzed the effect of aerolysin on human granulocytes (HL-60 cells). Proaerolysin could bind to these cells, was processed into active aerolysin, and led to membrane depolarization, indicating that granulocytes are potential targets for this toxin. Fura-2 measurements were used to analyze the effect of aerolysin on cytosolic [Ca2+] homeostasis. As expected for a pore-forming toxin, aerolysin addition led to Ca2+ influx across the plasma membrane. In addition, the toxin triggered Ca2+ release from agonist and thapsigargin-sensitive intracellular Ca2+ stores. This Ca2+ release was independent of the aerolysin-induced Ca2+ influx and occurred in two kinetically distinct phases: an initial rapid and transient phase and a second, more sustained, phase. The first, but not the second phase was sensitive to pertussis toxin. Activation of pertussis toxin-sensitive G-proteins appeared to be a consequence of pore formation, rather than receptor activation through aerolysin-binding, as it: (i) was not observed with a binding competent, insertion-incompetent aerolysin mutant, (ii) had a marked lag time, and (iii) was also observed in response to other bacterial pore-forming toxins (staphylococcal alpha-toxin, streptolysin O) which are thought to bind to different receptors. G-protein activation through pore-forming toxins stimulated cellular functions, as evidenced by pertussis toxin-sensitive chemotaxis. Our results demonstrate that granulocytes are potential target cells for aerolysin and that in these cells, Ca2+ signaling in response to a pore-forming toxin involves G-protein-dependent cell activation and Ca2+ release from intracellular stores.
Keywords		Bacterial Proteins — Bacterial Toxins/metabolism/ pharmacology — Calcium/ metabolism — Cell Membrane Permeability/drug effects — Chemotaxis, Leukocyte/drug effects — Digitonin/pharmacology — GTP-Binding Proteins/ metabolism — Granulocytes/drug effects/ metabolism — HL-60 Cells — Hemolysin Proteins/metabolism/ pharmacology — Humans — Ion Channels/ metabolism — Kinetics — Membrane Potentials — N-Formylmethionine Leucyl-Phenylalanine/pharmacology — Pertussis Toxin — Pore Forming Cytotoxic Proteins — Potassium/metabolism — Streptolysins/metabolism — Virulence Factors, Bordetella/pharmacology
Identifiers		DOI: 10.1074/jbc.273.29.18122 PMID: 9660770
Full text		Article - Limited access to UNIGE Other version: http://www.jbc.org/content/273/29/18122.full.pdf
Citation (ISO format)		KRAUSE, Karl-Heinz et al. Aerolysin induces G-protein activation and Ca2+ release from intracellular stores in human granulocytes. In: Journal of Biological Chemistry, 1998, vol. 273, n° 29, p. 18122-18129. https://archive-ouverte.unige.ch/unige:11393