Fig. 4. Analysis of the subcellular distribution of tomosyn-1 on a sucrose density gradient. A post-nuclear supernatant of INS-1E cells was loaded on a sucrose density gradient (0.45-2.0 M) and centrifuged for 18 hours at 110,000 g. Aliquots of the fractions containing 0.55-1.74 M sucrose were analyzed by western blotting using antibodies against tomosyn-1, granuphilin (secretory granule marker) and synaptophysin (synaptic-like vesicle marker).