ACETYLCHOLINESTERASE - C-TERMINAL DOMAINS, MOLECULAR-FORMS AND FUNCTIONAL LOCALIZATION

Acetylcholinesterase (AChE) possesses short C-terminal peptides that a re not necessary for catalytic activity. These peptides belong to diff erent classes (R, H, T, S) and define the post-translational processin g and targeting of the enzyme. In vertebrates, subunits of type H (ACh E(H)) and of type T (AChE(T)) are the most important: AChE(H) subunits produce glycolipid (GPI)-anchored dimers and AChE(T) subunits produce hetero-oligomeric forms such as membrane-bound tetramers in the mamma lian brain (containing a 20 kDa hydrophobic protein) and asymmetric co llagen-tailed forms in neuromuscular junctions (containing a specific collagen, ColQ). The T peptide allows the formation of tetrameric asse mblies with a proline-rich attachment domain (PRAD) of collagen ColQ. These complex molecular structures condition the functional localizati on of the enzyme in the supramolecular architecture of cholinergic syn apses. ((C)Elsevier, Paris).