 The Arp2 / 3 complex appears to be important in a variety of specialized cell functions that involve the actin cytoskeleton. The complex is found in cellular regions characterized by dynamic actin filament activity: in macropinocytic cups, in the leading edge of motile cells (lamellipodia), and in motile actin patches in yeast. In mammals and the social amoeba Dictyostelium discoideum it is required for phagocytosis. The complex has also been shown to be involved in the establishment of cell polarity and the migration of fibroblast monolayers in a wound-healing model. In mammalian oocytes, the Arp2 / 3 complex is involved in oocyte asymmetric division and polar body emission, which result from the failure of spindle migration (a unique feature of oocyte division) and cytokinesis. Moreover, enteropathogenic organisms like Listeria monocytogenes and Shigella use the Arp2 / 3 complex for actin-polymerization- dependent rocketing movements. The Arp2 / 3 complex also regulates the intracellular motility of endosomes, lysosomes, pinocytic vesicles, and mitochondria. Moreover, recent studies show that the Arp2 / 3 complex is essential for proper polar cell expansion in plants. Arp2 / 3 mutations in Arabidopsis thaliana result in abnormal filament organization, which in turn affects the expansion of trichomes, pavement cells, hypocotyl cells, and root hair cells.
