Protein Phosphorylation and Inhibition of Acetylcholine Release by Botulinum Neurotoxin A.
Abstract
There is considerable evidence supporting the role of phosphorylation and dephosphorylation of neuron specific proteins, e.g., synapsin and synaptophysin, in regulation of synaptic transmission. In this study concerning factors regulating presynaptic cholinergic function, the effect of Botulinum neurotoxin A (BoNT A), a potent inhibitor of acetylcholine release, on protein phosphorylation was examined. Synaptosomes were prepared from rat cerebral cortex and preincubated for 20 minutes with BoNT A (0-100nM) followed by 45 mins with 32P-orthophosphate. Proteins were separated by SDS-PAGE gels with radioactivity identified by autoradiography and liquid scintillation counting. BoNT A increased in a dose dependent manner, the steady state phosphorylation of several neuron specific proteins, e.g., the vesicle specific 38 kDa protein, synaptophysin which was confirmed by Western blot; a 43 kDa protein, (possibly B50), associated with neurotransmitter release and an unidentified 28 kDa component. The presence of BoNT A also increased the incorporation of (32)P into a doublet of 80-86 kDa, resembling the synapsins which depend on cAMP dependent kinase for phosphorylation. 4-Aminopyridine, known to reverse BoNT-induced inhibition of acetylcholine release, restored steady state phosphorylation toward control levels. These effects of BoNT A on protein phosphorylation may provide important insights into presynaptic factors regulating cholinergic neurotransmission and lead to sites for drug intervention in BoNT-induced toxicity.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 13, 1993
- Accession Number
- ADP008893
Entities
People
- Gerald H. Sterling
- John J. O'neill
- Karen E. Asermely
- Mary R. Mccafferty
Organizations
- Temple University