Fatty acylation of synaptotagmin in PC12 cells and synaptosomes.
Synaptotagmin I is localized to synaptic vesicles where it functions in the calcium-triggered release of neurotransmitters. Here we demonstrate that synaptotagmin I covalently incorporated [3H]palmitate after metabolic labelling of PC-12 cells and rat brain synaptosomes. Labeling was localized to a tryptic fragment that contains a cluster of cysteine residues adjacent to the molecule's single transmembrane anchor. Neutral hydroxylamine released the [3H]palmitate from this fragment and increased its electrophoretic mobility, demonstrating that acylation occurs at the membrane-proximal cysteine cluster. In addition, hydroxylamine-induced mobility shifts were also apparent for synaptotagmins II and III, suggesting that posttranslational palmitoylation via thioester bonds may be a general modification of all synaptotagmins.
Chapman
E R
ER
Howard Hughes Medical Institute, New Haven, Connecticut, USA.
Blasi
J
J
An
S
S
Brose
N
N
Johnston
P A
PA
Südhof
T C
TC
Jahn
R
R
D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia; D001921:Brain / Q000378:metabolism*; D017173:Caenorhabditis elegans; D002135:Calcium-Binding Proteins; D003545:Cysteine; D049832:Decapodiformes; D004330:Drosophila; D006801:Humans; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D016716:PC12 Cells; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013574:Synaptosomes / Q000378:metabolism*; D050863:Synaptotagmin I; D050857:Synaptotagmins
D002135:Calcium-Binding Proteins; D006898:Hydroxylamines; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D010169:Palmitic Acids; C494310:SYT1 protein, human; D050863:Synaptotagmin I; C494312:Syt1 protein, rat; D050857:Synaptotagmins; D019811:Hydroxylamine; D019308:Palmitic Acid; D003545:Cysteine