Interaction with a kinesin-2 tail propels choline acetyltransferase flow towards synapse

Traffic. 2012 Jul;13(7):979-91. doi: 10.1111/j.1600-0854.2012.01361.x. Epub 2012 Apr 26.


Bulk flow constitutes a substantial part of the slow transport of soluble proteins in axons. Though the underlying mechanism is unclear, evidences indicate that intermittent, kinesin-based movement of large protein-aggregates aids this process. Choline acetyltransferase (ChAT), a soluble enzyme catalyzing acetylcholine synthesis, propagates toward the synapse at an intermediate, slow rate. The presynaptic enrichment of ChAT requires heterotrimeric kinesin-2, comprising KLP64D, KLP68D and DmKAP, in Drosophila. Here, we show that the bulk flow of a recombinant Green Fluorescent Protein-tagged ChAT (GFP::ChAT), in Drosophila axons, lacks particulate features. It occurs for a brief period during the larval stages. In addition, both the endogenous ChAT and GFP::ChAT directly bind to the KLP64D tail, which is essential for the GFP::ChAT entry and anterograde flow in axon. These evidences suggest that a direct interaction with motor proteins could regulate the bulk flow of soluble proteins, and thus establish their asymmetric distribution.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Axonal Transport / genetics
  • Axonal Transport / physiology*
  • Carrier Proteins / metabolism
  • Choline O-Acetyltransferase / metabolism*
  • Cholinergic Neurons / enzymology
  • Cholinergic Neurons / metabolism
  • Drosophila / enzymology
  • Drosophila / genetics
  • Drosophila / metabolism
  • Drosophila Proteins / chemistry
  • Drosophila Proteins / metabolism*
  • Fluorescence Recovery After Photobleaching
  • Kinesins / chemistry
  • Kinesins / metabolism*
  • Larva / enzymology
  • Larva / metabolism
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / metabolism*
  • Protein Interaction Domains and Motifs
  • Synapses / enzymology
  • Synapses / metabolism


  • Carrier Proteins
  • Drosophila Proteins
  • Kap3 protein, Drosophila
  • Microtubule-Associated Proteins
  • Choline O-Acetyltransferase
  • kinesin 2 protein, Drosophila
  • Kinesins