Figure 4.

Synapsin IIa increases synaptic vesicle density. A, SV density was assayed in living neurons by measuring GFP synaptobrevin-2 targeting to presynaptic terminals. Shown is a representative image of a TKO neuron cotransfected with GFP-synaptobrevin-2 (green), ECFP-synapsin IIa (blue), and DsRed₂ (red). Representative synapses, indicated by accumulation of synaptobrevin-2 and synapsin IIa, are indicated by white arrows in the top panel. B, SV density was assayed in untreated TWT (n = 15) and TKO (n = 8) neurons, as well as TKO neurons cotransfected with synapsin Ia (n = 8), Ib (n = 8), IIa (n = 12), and IIIa (n = 9). Only synapsin IIa significantly (*p < 0.05) increased SV density.