Trimerization domain of the collagen tail of acetylcholinesterase.
In the collagen-tailed forms of cholinesterases, each subunit of a specific triple helical collagen, ColQ, may be attached through a proline-rich domain (PRAD) situated in its N-terminal noncollagenous region, to tetramers of acetylcholinesterase (AChE) or butyrylcholinesterase (BChE). This heteromeric assembly ensures the functional anchoring of AChE in extracellulare matrices, for example, at the neuromuscular junction. In this study, we analyzed the influence of deletions in the noncollagenous C-terminal region of ColQ on its capacity to form a triple helix. We show that an 80-residue segment located downstream of the collagenous regions contains the trimerization domain, that it can form trimers without the collagenous regions, and that a pair of cysteines located at the N-boundary of this domain facilitates oligomerization, although it is not absolutely required. We further show that AChE subunits can associate with nonhelical collagen ColQ monomers, forming ColQ-associated tetramers (G4-Q), which are secreted or are anchored at the cell surface when the C-terminal domain of ColQ is replaced by a GPI-addition signal.
Bon
Suzanne
S
Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS UMR 8544, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France.
Ayon
Annick
A
Leroy
Jacqueline
J
Massoulié
Jean
J
D000110:Acetylcholinesterase / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D019556:COS Cells; D003094:Collagen / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000502:physiology; D014101:Torpedo / Q000235:genetics; D014162:Transfection
D009124:Muscle Proteins; D003094:Collagen; D000110:Acetylcholinesterase; C114027:COLQ protein, human