sentences:  Recently, however, it has been found that dynamin, the protein responsible for breaking the newly formed vesicular bud off the inside of the plasma membrane, can associate with the SH3 domain of cortactin.Since cortactin recruits the Arp2/3 complexes that lead to actin polymerization, this suggests that it may play an important part in linking vesicle formation to the as yet unknown functions actin has in endocytosis.Amplification of the genes encoding cortactin—in humans, EMS1—has been found to occur in certain tumors.