A tetrameric acetylcholinesterase from the parasitic nematode Dictyocaulus viviparus associates with the vertebrate tail proteins PRiMA and ColQ

作者：Pezzementi Leo^*; Krejci Eric; Chatonnet Arnaud; Selkirk Murray E; Matthews Jacqueline B

来源：Molecular and Biochemical Parasitology, 2012, 181(1): 40-48.

DOI：10.1016/j.molbiopara.2011.10.005

• Acetylcholinesterase
• Cholinergic nervous system
• Dictyocaulus viviparus
• ColQ
• PRiMA
• Poly-L-proline
• Evolution

Dictyocaulus viviparus causes a serious lung disease of cattle. Similar to other parasitic nematodes, D. viviparus possesses several acetylcholinesterase (AChE) genes, one of which encodes a putative neuromuscular AChE, which contains a tryptophan (W) amphiphilic tetramerization (WAT) domain at its C-terminus. In the current study, we describe the biochemical characterization of a recombinant version of this WAT domain-containing AChE. To assess if the WAT domain is biologically functional, we investigated the association of the recombinant enzyme with the vertebrate tail proteins, proline-rich membrane anchor (PRiMA) and collagen Q (ColQ), as well as the synthetic polypeptide poly-L-proline. The results indicate that the recombinant enzyme hydrolyzes acetylthiocholine preferentially and exhibits inhibition by excess substrate, a characteristic of AChEs but not butyrylcholinesterases (BChEs). The enzyme is inhibited by the AChE inhibitor, BW284c51, but not by the BChE inhibitors, ethopropazine or iso-OMPA. The enzyme is able to assemble into monomeric (G(1)), dimeric (G(2)), and tetrameric (G(4)) globular forms and can also associate with PRIMA and ColQ which contain proline-rich attachment domains (PRADs). This interaction is likely to be mediated via WAT-PRAD interactions, as the enzyme also assembles into tetramers with the synthetic polypeptide poly-L-proline. These interactions are typical of AChE(T) subunits. This is the first demonstration of an AChET from a parasitic nematode that can assemble into heterologous forms with vertebrate proteins that anchor the enzyme in cholinergic synapses. We discuss the implications of our results for this particular host/parasite system and for the evolution of AChE.

• 出版日期2012-1