Acetylcholinesterase (ACHE; EC 3.1.1.7) controls synaptic and neurohumoral cholinergic activity by hydrolyzing the neurotransmitter acetylcholine. ACHE function relies on precise regulation of its expression and localization. In particular, alternative splicing of the 3-prime region of ACHE results in ACHE isoforms with distinct C-terminal peptides that determine posttranslational maturation and oligomeric assembly. Acetylcholinesterase is also found on the red blood cell membranes, where it constitutes the Yt blood group antigen. (H322N)