Relationship of actin polymerization and depolymerization to light scattering in human neutrophils: dependence on receptor occupancy and intracellular Ca++.

作者：Larry A. Sklar, Geneva M. Omann, Richard G. Painter · 发表于：The Journal of Cell Biology · 年份：1985 · DOI：10.1083/jcb.101.3.1161 · 被引用次数：175 · 研究领域：S100 Proteins and Annexins、Cellular Mechanics and Interactions、Cell Adhesion Molecules Research

When exposed to the N-formylated chemoattractant peptides, neutrophils undergo a transient ruffling followed by a polarization that involves a redistribution of F-actin (Fechheimer, M., and S. H. Zigmond, 1983, Cell Motil., 3:349-361). The cells also undergo a biphasic right angle light scatter response whose first phase is maximal 10-15 s after exposure to the stimulus, and whose second phase is longer in duration and maximal only after 1 min or more (Yuli, I., and R. Snyderman, 1984, J. Clin. Invest. 73:1408-1417). We now report that the first phase is accompanied by a transient polymerization of actin (monitored by cytometric analysis of phallacidin staining according to the method of Howard, T. H., and W. H. Meyer, 1984, J. Cell Biol., 98:1265-1271) and the second phase is accompanied by a more sustained polymerization of actin. Based on correlated measurements of ligand binding (Sklar, L. A., D. A. Finney, Z. G. Oades, A. J. Jesaitis, R. G. Painter, and C. G. Cochrane, 1984, J. Biol. Chem., 259:5661-5669) and intracellular Ca++ elevation (under conditions where we use the fluorescent Ca++ chelator Quin 2 to modulate intracellular Ca++ levels), we conclude that this first phase requires less than 100 receptors/cell (out of 50,000) and does not require the release of intracellular stores of Ca++. In contrast, the sustained polymerization requires both the occupancy of thousands of receptors (an estimated 10% of the receptors per minute) and may be somewhat sensitive to the...