RNA transport and local protein synthesis in the dendritic compartment.

Abstract

The shape and composition of the postsynaptic membrane depend on synaptic activity and change throughout the lifetime of the synapse (for references, see Albright et al. 2000). The mechanisms underlying the establishment of the receptor mosaic at the postsynaptic membrane (synthesis, processing, targeting and insertion of receptors) are still poorly understood. It is currently assumed that receptors, like other transmembrane proteins, are targeted to the plasma membrane via the somatic secretory pathway. Hypotheses concerning receptor-targeting mechanisms in the central neuron derive from two different systems: the neuromuscular junction (for references, see Sanes and Lichtman 1999) and the epithelial cell as a paradigm for neuron polarity (Dotti and Simons 1990). Recently, sorting signals have been identified for the metabotropic glutamate receptors (mGluRs, Stowell and Craig 1999). However, the machinery allowing a vectorial transport of neurotransmitter receptors from the cell soma to the postsynaptic differentiation has not been identified yet. The most challenging question is: how can thousands of signals, which notify minute changes occurring at each postsynaptic differentiation and arise from a large number of synapses, be treated somatically and subsequently induce a synaptic change, some synapses being located on dendrites hundreds of microns away?