TARGETING ACETYLCHOLINESTERASE MOLECULES TO THE NEUROMUSCULAR SYNAPSE

The functional integrity of the neuromuscular synapse requires that su fficient numbers of acetylcholinesterase (AChE) molecules be localized on the specialized extracellular matrix between the nerve terminal an d the post-synaptic membrane. Multiple interrelated levels of regulati on are necessary to accomplish this complex task including the spatial and temporal restriction of AChE mRNA expression within the muscle fi ber, local translation and assembly of AChE polypeptides, and focused accumulation of AChE molecules on the extracellular matrix. This is ac complished in part through the organization of other extracellular mat rix molecules into a complex which further associates with acetylcholi ne receptors and their accompanying molecules. Finally, the mature neu romuscular junction contains molecules which can act as receptors for the attachment of AChE which in turn may allow for the turnover of thi s enzyme at the synapse. This brief review will focus mainly on contri butions from our laboratory towards understanding the mechanisms invol ved in organizing AChE molecules at the neuromuscular synapse. ((C)Els evier, Paris).