Figure 8.
BLOC-1 selectively regulates synaptic vesicle levels of PI4KIIα and VAMP7-TI. Glycerol gradient velocity sedimentation of S2 fractions from BLOC-1-deficient mutedmu/mu (open circles) and control Muted+/mu (closed circles) mouse brains. Synaptic vesicle fractions were resolved by SDS-PAGE and analyzed by Western blot for the indicated protein. Protein levels were quantified using NIH Imager and were standardized to control muted+/mu levels. Synaptic vesicle levels of ZnT3, VGAT, Sphysin, VAMP2, VGLUT1, and SV2 are unaffected by the loss of muted. However, the peak synaptic vesicle levels of both VAMP7-TI (p < 0.0005) and PI4KIIα (p < 0.01) increase in Mutedmu/mu. ZnT3, n = 3, 3; VAMP7-TI, n = 4, 4; VGAT, n = 4, 4; Sphysin, n = 4, 9; PI4KIIα, n = 4, 4; SV2, n = 3, 3; VAMP2, n = 3, 3; and VGlut1, n = 4, 4 (number of independent fractionations, number of independent Western blot analyses). Wilcoxon–Mann–Whitney test. Representative blots for these experiments can be found in Supplemental Figure 8.