Dynamin-2 Controls Actin Remodeling for Efficient Complement Receptor 3-Mediated Phagocytosis.

BACKGROUND INFORMATION:Phagocytosis is the mechanism of the internalization of large particles, microorganisms and cellular debris. The complement pathway represents one of the first mechanisms of defense against infection and the complement receptor 3 (CR3), which is highly expressed on macrophages, is a major receptor for many pathogens and debris. Key to dissecting the mechanisms by which CR3-mediated phagocytosis occurs, is understanding how the complex actin binding protein machinery and associated regulators interact with actin during phagocytosis, from triggering of receptor, through to phagosome formation and closure.RESULTS:Here, we reveal that Dynamin-2 is recruited concomitantly with polymerized actin at the phagocytic cup and during phagosome formation and closure. Inhibition of Dynamin activity leads to stalled phagocytic cups and a decrease in the amount of F-actin at the site of phagocytosis.CONCLUSIONS:Dynamin-2 regulates the assembly of the F-actin phagocytic cup for successful CR3-mediated phagocytosis.SIGNIFICANCE:These results highlight an important role for Dynamin-2 in actin remodeling downstream of integrins.