[Ca2+]i-transients and actin polymerization in human neutrophils under stimulation with GROα and complement fragment C5a
The neutrophil chemotaxins, complement fragment C5a (C5a) and GROα, induced the mobilization of Ca2+ from intracellular stores and the polymerization of actin in human neutrophils as assayed by flow cytometric measurements. [Ca2+]i-transients developed as an “all-or-none” response. Individual neutrophils required different threshold concentrations of added ligand to induce [Ca2+]i-transients which were then always maximal. In contrast, chemotaxin-induced formation of actin filaments in single neutrophils occurred in a dose-dependent manner. Pertussis toxin blocked chemotaxin-induced actin polymerization and [Ca2+]i-transients indicating that both cell responses shared initial activation steps such as ligand binding and activation of guanine nucleotide-binding proteins (G-proteins).
Key wordsGROα Complement fragment C5a Actin Ca2+-transients
Cytosolic free Ca2+
Complement fragment C5a
Unable to display preview. Download preview PDF.
- D. J. Kelvin, D. F. Michiel, J. A. Johnston, A. R. Lloyd, H. Sprenger, J. J. Oppenheim and J.-M. Wang,Ohemokines and serpentines: The molecular biology of chemokine receptors. J. Leuk. Biol.54, 604–612 (1993).Google Scholar
- P. Gierschik, D. Sidiropoulos and K. H. Jakobs,Two distinct G i-proteins mediate formyl peptide receptor signal transduction in human leukemia (HL-60) cells. J. Biol.264, 21470–21473 (1989).Google Scholar
- B. Alberts, D. Bray, J. Lewis, M. Raff K. Roberts and J. D. Watson,The nervous system. InMolecular Biology of the Cell. pp. 1059–1136, Garland, New York 1989.Google Scholar