Dynamin is a member of a group of nerve terminal proteins called dephosphins that regulate synaptic vesicle endocytosis (Cousin et al., 2001; Graham et al., 2002; Tsuboi et al., 2002). Cyclin dependent protein kinase 5 phosphorylates dynamin at Ser774 and Ser778 that are the phosphorylation sites on dynamin phosphorylated in vivo (Tan et al., 2003). Phosphorylation of Ser774 by GSK3 has recently been shown to control activity-dependent bulk endocytosis of synaptic vesicles (Clayton et al., 2010)