Dynamin 2 is required for phagocytosis in macrophages

Cells internalize soluble ligands through endocytosis and large particles t hrough actin-based phagocytosis. The dynamin family of GTPases mediates the scission of endocytic vesicles from the plasma membrane. We report here th at dynamin 2, a ubiquitously expressed dynamin isoform, has a role in phago cytosis in macrophages. Dynamin 2 is enriched on early phagosomes, and expr ession of a dominant-negative mutant of dynamin 2 significantly inhibits pa rticle internalization at the stage of membrane extension around the partic le. This arrest in phagocytosis resembles that seen with inhibitors of phos phoinositide 3-kinase (PI3K), and inhibition of PI3K prevents the recruitme nt of dynamin to die site of particle binding. Although expression of mutan t dynamin in macrophages inhibited particle internalization, it had no effe ct on the production of inflammatory mediators elicited by particle binding .