Figure 2.

α-Synuclein interacts transiently with synaptic components. A, A single, isolated hippocampal bouton expressing GFP-α-synuclein was photobleached at high laser power, and recovery was monitored every 400 ms thereafter. GFP-α-synuclein recovers rapidly after photobleaching. The two synapses outside the bleached box show a reduction in fluorescence during recovery of the bleached region. The color scale is shown to the right. Scale bar, 2 μm. B, The intensity of fluorescence at the bleached synapse was quantified and expressed as a percentage of initial fluorescence, with fluorescence after the bleach defined as zero. GFP (green) and GFP-A30P (blue) recover with similar, rapid kinetics after photobleaching, consistent with their behavior as soluble proteins. In contrast, GFP-α-synuclein (red) recovers more slowly, indicating a distinct but rapidly reversible interaction with synaptic components. GFP-synapsin (GFPsyp; purple) recovers more slowly than α-synuclein, consistent with a higher affinity for synaptic vesicles. GFP-SV2 (black) does not recover after photobleaching, indicating that synaptic vesicles do not exchange between synapses, at least during this time scale. Data shown are averages ± SEM of 30-40 boutons per construct.