FIGURE 1.

vGlut has the lowest steady-state presynaptic surface fraction of all SV cargo proteins. Steady-state surface fraction of SV cargos was determined by examining the fractional change in fluorescence in response to brief NH₄Cl application at hippocampal synapses expressing SV proteins containing an exofacial/luminal pHluorin tag: vGlut1 (vG, 1.6 ± 0.56%, n = 9), SV2 (1.7 ± 0.7%, n = 8), synaptophysin (Syphy, 9.9 ± 1.3%, n = 10), VAMP2 (19.7 ± 2.6%, n = 8) and synaptotagmin 1 (Syt1, 26.5 ± 3.0%, n = 8). Error bars indicate S.E.