Dense core vesicle dynamics in Caenorhabditis elegans neurons and the role of kinesin UNC-104

Traffic. 2004 Jul;5(7):544-59. doi: 10.1111/j.1600-0854.2004.00195.x.

Abstract

We have developed a model system in Caenorhabditis elegans to perform genetic and molecular analysis of peptidergic neurotransmission using green fluorescent protein (GFP)-tagged IDA-1. IDA-1 represents the nematode ortholog of the transmembrane proteins ICA512 and phogrin that are localized to dense core secretory vesicles (DCVs) of mammalian neuroendocrine tissues. IDA-1::GFP was expressed in a small subset of neurons and present in both axonal and dendritic extensions, where it was localized to small mobile vesicular elements that at the ultrastructural level corresponded to 50 nm electron-dense objects in the neuronal processes. The post-translational processing of IDA-1::GFP in transgenic worms was dependent on the neuropeptide proprotein convertase EGL-3, indicating that the protein was efficiently targeted to the peptidergic secretory pathway. Time-lapse epifluorescence microscopy of IDA-1::GFP revealed that DCVs moved in a saltatory and bidirectional manner. DCV velocity profiles exhibited multiple distinct peaks, suggesting the participation of multiple molecular motors with distinct properties. Differences between velocity profiles for axonal and dendritic processes furthermore suggested a polarized distribution of the molecular transport machinery. Study of a number of candidate mutants identified the kinesin UNC-104 (KIF1A) as the microtubule motor that is specifically responsible for anterograde axonal transport of DCVs at velocities of 1.6 microm/s-2.7 microm/s.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Autoantigens
  • Axons / metabolism
  • Biological Transport
  • Blotting, Western
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology*
  • Cytosol / metabolism
  • Dendrites / metabolism
  • Green Fluorescent Proteins / metabolism
  • Kinesin / metabolism
  • Membrane Proteins / metabolism
  • Membrane Proteins / pharmacology
  • Microscopy, Fluorescence
  • Microscopy, Immunoelectron
  • Models, Biological
  • Mutation
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology*
  • Neurons / metabolism*
  • Protein Structure, Tertiary
  • Protein Tyrosine Phosphatases / metabolism
  • Protein Tyrosine Phosphatases / pharmacology
  • Receptor-Like Protein Tyrosine Phosphatases, Class 8
  • Time Factors
  • Transgenes

Substances

  • Autoantigens
  • Caenorhabditis elegans Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • UNC-104 protein, C elegans
  • Green Fluorescent Proteins
  • PTPRN protein, human
  • PTPRN2 protein, human
  • Protein Tyrosine Phosphatases
  • Receptor-Like Protein Tyrosine Phosphatases, Class 8
  • Kinesin