The decentralized approach to decision-making in neurons, in which synaptic plasticity is locally determined, implies that transcription (which occurs back in the cell body) cannot be relied upon as a means of regulation. Instead, messenger RNAs (mRNAs), quite possibly in an inactive state, are transported along dendrites to postsynaptic regions where they may be translated when protein is needed.
Kanai et al. have used a battery of techniques to identify components, including the RNA-binding protein staufen and the mRNA encoding calcium/calmodulin protein kinase II (CaMKII), that are carried by the molecular motor kinesin in the form of large 1000S granules. Staufen is already known to participate in the transport and localization of mRNAs in the Drosophila embryo, and CaMKII is a central player in activity-dependent phosophorylation at the synapse. The authors propose that core components would assemble on mRNAs to form granules and that cell- or dendrite-specific factors would be added as requisitioned by synaptic events. — GJC
Neuron 43, 513 (2004).