Okadaic acid disrupts synaptic vesicle trafficking in a ribbon-type synapse.

Published

Journal Article

Protein phosphorylation plays an essential role in regulating synaptic transmission and plasticity. However, regulation of vesicle trafficking towards and away from the plasma membrane is poorly understood. Furthermore, the extent to which phosphorylation modulates ribbon-type synapses is unknown. Using the phosphatase inhibitor okadaic acid (OA), we investigated the influence of persistent phosphorylation on vesicle cycling in goldfish bipolar cells. We followed uptake of FM1-43 during vesicle recycling in control and OA-treated cells. FM1-43 fluorescence spread to the center of control synaptic terminals after depolarization elicited Ca2+ influx. However, OA (1-50 nm) impaired this spatial spread of FM1-43 in a dose-dependent manner. Capacitance measurements revealed that OA (50 nm) did not modify either the amount or kinetics of exocytosis and endocytosis evoked by depolarizing pulses. The extremely low concentrations of OA (1-5 nm) sufficient to observe the inhibition of vesicle mobility implicate phosphatase 2A (PP2A) as a major regulator of vesicle trafficking after endocytosis. These results contrast with those at the neuromuscular junction where OA enhances lateral movement of vesicles between distinct vesicle clusters. Thus, our results suggest that phosphatases regulate vesicle translocation at ribbon synapses in a different manner than conventional active zones.

Full Text

Duke Authors

Cited Authors

  • Guatimosim, C; Hull, C; Von Gersdorff, H; Prado, MAM

Published Date

  • September 2002

Published In

Volume / Issue

  • 82 / 5

Start / End Page

  • 1047 - 1057

PubMed ID

  • 12358752

Pubmed Central ID

  • 12358752

Electronic International Standard Serial Number (EISSN)

  • 1471-4159

International Standard Serial Number (ISSN)

  • 0022-3042

Digital Object Identifier (DOI)

  • 10.1046/j.1471-4159.2002.01029.x

Language

  • eng