Figure 5.

Characterization of the membranes containing p18 after fusion. A PNS was prepared from PC12 cells labeled with [³⁵S]sulfate for 30 min. One-half of this PNS was kept on ice while the remainder was incubated under standard conditions for fusion with PC2-ISGs. Both the starting material and the reaction mixture were loaded onto velocity gradients and subjected to fractionation. Fractions 2–4 from the velocity gradients were pooled, and one-fifths were analyzed for p18 using the standard incubation for processing while the remaining four-fifths were subjected to equilibrium gradient centrifugation and fractionation. (a) Samples of the velocity gradient pools analyzed for p86, or (b) subjected to processing and then immunoprecipitation with anti-p18 antibodies from either the starting material (pre fusion) or after fusion (post fusion). (c) Samples of equilibrium gradient fractions 5–11 from the gradient loaded with the starting material were analyzed for p86, or (d) equilibrium gradient fractions 5–11 from the gradient loaded with the fusion reaction were subjected to processing followed by immunoprecipitation to detect p18 as above. Analysis of p86 was performed by SDS-PAGE followed by fluorography.