ABSTRACT
The average lifespan of neutrophil leucocytes released from bone marrow in healthy individuals is believed to be on the order of hours. The locomotion of neutrophils, as with locomotion of other crawling cells like fibroblasts, is assumed to be due to the activity of actin filament meshworks and other actin filament structures in conjunction with myosin. According to the localization of phalloidin fluorescence in resting cells, essentially all the polymerized actin is present in a thin cortical submembranous layer, although others have noted a diffuse cytoplasmic fluorescence. The chapter focuses on the organization of actin filaments in neutrophils, their reorganization during phagocytosis and locomotion, and the mechanism by which receptors might regulate actin filament function to mediate these motile phenomena. For receptor-mediated chemotaxis it is assumed that receptor occupation, albeit by entirely mysterious mechanisms, regulates the motile machinery of cells to result in net upgradient movement.
