Figure 7.

BFA and monensin do not inhibit palmitoylation of all cellular proteins. (A) PC12 cells were labeled with [³H]palmitate for 1 h in the absence (lane 1) or presence of 10 μg/ml BFA (lane 2) or 10 μM monensin (lane 3). Cell lysates were resolved by SDS-PAGE, and the incorporation of [³H]palmitate into proteins was detected by fluorography. (B) N2A cells were labeled with [³⁵S]methionine or [³H]palmitate for 1 h in the absence or presence of BFA. G_oα and G_iα subunits labeled with [³⁵S]methionine (lanes 1 and 2) or [³H]palmitate (lanes 5 and 6) were immunoprecipitated. Note how palmitoylation of G protein α subunits is not affected by treatment with BFA. SNAP-25 labeled with [³⁵S]methionine (lanes 3 and 4) or [³H]palmitate (lanes 7 and 8) was immunoprecipitated. Inhibition of SNAP-25 palmitoylation by BFA is apparent from reduced labeling with [³H]palmitate (lane 8). (C) NG108 cells were labeled with [³H]palmitate for 1 h in the presence or absence of BFA, and SNAP-25 (lanes 3 and 4) and GAP-43 (lanes 1 and 2) were immunoprecipitated from total cell lysates. Equal amounts of protein in each lane was demonstrated by immunoblotting an aliquot of the immunoprecipitated samples (bottom panel). Palmitoylation of both GAP-43 and SNAP-25 were inhibited by BFA in NG108 cells.