The C-terminal T peptide of cholinesterases: structure, interactions, and influence on protein folding and secretion.
Mammalian cholinergic tissues mostly express the T splice variant of acetylcholinesterase, in which the catalytic domain is associated with a C-terminal peptide of 40 residues, called the t peptide (Massoulié, 2002). Homologous t peptides exist in all vertebrate cholinesterases, acetylcholinesterases (AChEs), and butyrylcholinesterases (BChEs): they contain a series of seven conserved aromatic residues, including three tryptophans, and a cysteine at position-4 of their C-terminus. The major AChE isozyme of the nematode Caenorhabditis elegans also contains a similar peptide. Although the C-terminal t peptides do not seem to affect the catalytic activity of cholinesterases, they determine their physiological function, because they allow cholinesterase subunits of type T to form oligomers and to associate with structural anchoring proteins. When reduced to their catalytic domain, AChE subunits without a t peptide are active but remain monomeric and soluble.
Massoulié
Jean
J
Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS UMR8544, Ecole Normale Supérieure, Paris, France. jean.massoulie@biologie.ens.fr
Bon
Suzanne
S
D000595:Amino Acid Sequence; D002802:Cholinesterases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry*; D017510:Protein Folding; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D046912:Multiprotein Complexes; D010446:Peptide Fragments; D002802:Cholinesterases