The localization, trafficking and retrograde transport of BDNF bound to p75NTR in sympathetic neurons

Mol Cell Neurosci. 2006 Aug;32(4):387-402. doi: 10.1016/j.mcn.2006.06.001. Epub 2006 Jul 14.

Abstract

BDNF, through p75NTR, promotes apoptosis and inhibits axonal growth of sympathetic neurons, antagonizing the pro-survival and axon growth-promoting actions of NGF through TrkA. While the trafficking of the TrkA:NGF complex is well characterized, little is known about p75NTR:BDNF trafficking in these neurons. Here we show that BDNF binds to and appears inside sympathetic neurons relatively slowly, although the temperature-sensitive internalization step itself is rapid. P75NTR internalization is partially sensitive to disruption of clathrin- or raft-mediated internalization, while that of TrkA is entirely clathrin-mediated. P75NTR, but not Trk, associates with neurotrophins in lipid rafts and coimmunoprecipitates with the truncated beta-caveolin-1 isoform. Finally, we directly visualize the retrograde transport of p75NTR ligands to cell bodies, which is insensitive to inhibitors of Trk retrograde transport, suggesting mechanistic differences. We postulate that beta-caveolin-1-containing lipid rafts and possibly intracellular endosomes might be compartments to which p75NTR:BDNF complexes are trafficked separately from Trk.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Biotinylation / methods
  • Blotting, Western / methods
  • Brain-Derived Neurotrophic Factor / metabolism*
  • Cells, Cultured
  • Drug Interactions
  • Endocytosis / drug effects
  • Endocytosis / physiology
  • Enzyme Inhibitors / pharmacology
  • Enzyme-Linked Immunosorbent Assay / methods
  • Green Fluorescent Proteins / metabolism
  • Immunoprecipitation / methods
  • Ionophores / pharmacology
  • Neurons / drug effects
  • Neurons / physiology*
  • Nystatin / pharmacology
  • Protein Transport / drug effects
  • Protein Transport / physiology
  • Rats
  • Receptor, Nerve Growth Factor / metabolism*
  • Receptor, trkB / metabolism
  • Sucrose / pharmacology
  • Sympathetic Nervous System / cytology*
  • Transfection / methods

Substances

  • Brain-Derived Neurotrophic Factor
  • Enzyme Inhibitors
  • Ionophores
  • Receptor, Nerve Growth Factor
  • Nystatin
  • Green Fluorescent Proteins
  • Sucrose
  • Receptor, trkB