title: The 25 kDa synaptosomal-associated protein SNAP-25 is the major methionine-rich polypeptide in rapid axonal transport and a major substrate for palmitoylation in adult CNS.
abstract: A conspicuous correlate of the developmental transformation of axonal growth cones to synaptic terminals is a marked increase in synthesis and axonal transport of a methionine-rich, acidic polypeptide of approximately 25 kDa. This polypeptide, designated "super protein" (SuP), is the most prominent species among methionine-labeled proteins conveyed by rapid axonal transport in mature CNS and PNS neurons of warm- and cold-blooded vertebrates. We show here that SuP is identical to SNAP-25, a highly conserved synaptic protein of known primary structure, by immunoprecipitation with anti-SNAP-25 antiserum of SuP labeled with 35S-methionine and transported by retinal ganglion cells of rat and cat. In addition, we show that SNAP-25/SuP is the most prominent species among retinal polypeptides that incorporate 3H-palmitate in vivo, that it is fatty acylated through a hydroxylamine-labile, thioester bond, and that palmitoylated SNAP-25/SuP is axonally transported. Thus, SNAP-25/SuP is a rapidly transported constituent of the presynaptic apparatus and a major neuronal substrate for long-chain fatty acylation.
mesh_terms: D000818:Animals; D001370:Axonal Transport; D002415:Cats; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005829:Geniculate Bodies / Q000378:metabolism*; D008565:Membrane Proteins; D008715:Methionine / Q000378:metabolism*; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D009900:Optic Nerve / Q000378:metabolism*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D051381:Rats; D012160:Retina / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D013477:Superior Colliculi / Q000378:metabolism*; D050825:Synaptosomal-Associated Protein 25; D014316:Tritium
chemical_list: D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010169:Palmitic Acids; C494210:Snap25 protein, rat; D013462:Sulfur Radioisotopes; D050825:Synaptosomal-Associated Protein 25; D014316:Tritium; D019308:Palmitic Acid; D008715:Methionine