Phosphorylation of 25-kDa synaptosome-associated protein. Possible involvement in protein kinase C-mediated regulation of neurotransmitter release.
Protein kinase C-mediated phosphorylation of a 25-kDa synaptosome-associated protein (SNAP-25) was examined in living PC12 cells. Phorbol 12-myristate 13-acetate treatment enhanced high potassium-induced [3H]-norepinephrine release, and a 28-kDa protein recognized by an anti-SNAP-25 antibody was phosphorylated on Ser residues. The molecular size of the phosphorylated band decreased slightly following treatment with Clostridium botulinum type A neurotoxin, whereas the band disappeared after treatment with botulinum type E neurotoxin, indicating that the 28-kDa protein was SNAP-25. A phosphorylation is likely to occur at Ser187, as this is the only Ser residue located between the cleavage sites of botulinum type A and E neurotoxins. SNAP-25 of PC12 cells was phosphorylated by purified protein kinase C in vitro, and the amount of syntaxin co-immunoprecipitated with SNAP-25 was decreased by phosphorylation. These results suggest that the phosphorylation of SNAP-25 may be involved in protein kinase C-mediated regulation of catecholamine release from PC12 cells.
Shimazaki
Y
Y
Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194, Japan.
Nishiki
T
T
Omori
A
A
Sekiguchi
M
M
Kamata
Y
Y
Kozaki
S
S
Takahashi
M
M
D000818:Animals; D000911:Antibodies, Monoclonal; D000941:Antigens / Q000737:chemistry; D001905:Botulinum Toxins / Q000494:pharmacology; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D009498:Neurotoxins / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D050765:Qa-SNARE Proteins; D051381:Rats; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D033921:Vesicular Transport Proteins
D000911:Antibodies, Monoclonal; D000941:Antigens; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D050765:Qa-SNARE Proteins; D050600:SNARE Proteins; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins; D010768:Phosphoserine; D011493:Protein Kinase C; D001905:Botulinum Toxins; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D009638:Norepinephrine