Synaptobrevin 2 is palmitoylated in synaptic vesicles prepared from adult,but not from embryonic brain

Neuronal SNARE-proteins such as synaptobrevin, SNAP 25, and synaptotagmin a re key players during neurosecretion. So far palmitoylation of SNAP-25 and synaptotagmin 1 have been described in vivo. Here we have analyzed palmitoy lation of the SNARE-proteins synaptobrevin 2 and synaptotagmin in vitro usi ng synaptosomal and synaptic vesicle preparations from rat brain. Labeling of synaptic vesicles prepared from adult brain with [H-3]palmitate revealed synaptobrevin 2 besides synaptotagmin 1 as major palmitoylated proteins. [ H-3]palmitoylation of synaptobrevin 2 was resistant to chloroform/methanol extraction, but sensitive to reducing agents indicating a covalent fatty ac id bond to cysteine residues. Palmitoylation of synaptobrevin 2 was also co nfirmed using endogenous synaptobrevin 2 present in PC-12 cells and synapto brevin 2 expressed with a vacciniavirus system in Cos cells. In contrast to the situation seen with membrane preparations obtained from adult brain, s ynaptic vesicles prepared from embryonic rat brain did not support [H-3]pal mitoylation of synaptobrevin and synaptotagmin. These results suggest, that both synaptobrevin 2 and synaptotagmin were efficiently palmitoylated from mature synaptic vesicles. However, at least one component of the palmitoyl ation machinery is developmentally upregulated.