Figure 2. VTVs utilize Sec22b as a functional v-SNARE to fuse with hepatic cis-Golgi.

VTVs (150 μg of protein) containing [¹⁴C]TAG and [³H]apoB100 were incubated at 4 °C with 10 μl of pre-immune IgG, 10 μl of anti-Sec22b antibodies, 10 μl of anti-VAMP7 antibodies, 10 μl of anti-Sar1 antibodies or 10 μl of boiled anti-Sec22b antibodies. Antibodies in each case were removed by washing, and the treated VTVs were incubated with non-radiolabelled cis-Golgi (300 μg of protein) at 37 °C in the presence or absence (no cyto) of cytosol (0.5 mg of protein). (A) After incubation, Golgi membranes were separated and the Golgi-associated [¹⁴C]TAG was extracted (A) or the Golgi-associated [³H]apoB100 was immunoprecipitated (B). Total [¹⁴C]TAG (A) or [³H]apoB100 (B) levels (in d.p.m.) were determined. For details, see the Experimental section. Results are means + S.E.M. (n = 4).