A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis.
Ferguson SM., Brasnjo G., Hayashi M., Wölfel M., Collesi C., Giovedi S., Raimondi A., Gong L-W., Ariel P., Paradise S., O'toole E., Flavell R., Cremona O., Miesenböck G., Ryan TA., De Camilli P.
Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.