title: Three acetylcholinesterases of the pinewood nematode, Bursaphelenchus xylophilus: insights into distinct physiological functions.
abstract: Acetylcholinesterase (AChE) plays a key role in postsynaptic transmission in most animals. Nematodes encode multiple AChEs, implying its functional diversity. To explore physiological functions of multiple AChEs, three distinct AChEs (BxACE-1, BxACE-2, and BxACE-3) were identified and characterized from the pinewood nematode. Sequencing comparison with Torpedo AChE and Caenorhabditis elegans ACEs identified choline-binding site, catalytic triad functional site, three internal disulfide bonds and aromatic residues for the catalytic gorge. Transcriptional profiling by quantitative real-time PCR revealed that BxACE-3 is more actively transcribed than BxACE-1 (2-3 times) and BxACE-2 (9-18 times) in both propagative and dispersal stages. The three BxACEs were functionally expressed using baculovirus system. Kinetic analysis of in vitro-expressed BxACEs revealed that the substrate specificity was highest in BxACE-1 whereas the catalytic efficiency was highest in BxACE-2. In inhibition assay, BxACE-3 showed the lowest inhibition rate. Taken together, it appears that both BxACE-1 and BxACE-2 play common but non-overlapping roles in synaptic transmission, whereas BxACE-3 may have non-neuronal functions. The current findings should provide valuable insights into the evolutionary process and various physiological roles of AChE.
authors.affiliation: Research Institute for Agriculture and Life Science, Seoul National University, Seoul, Republic of Korea.
authors.forename: Jae Soon
authors.initials: JS
authors.lastname: Kang
authors.forename: Dae-Weon
authors.initials: DW
authors.lastname: Lee
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Koh
authors.forename: Si Hyeock
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000235:genetics; D020134:Catalytic Domain; D003001:Cloning, Molecular; D004220:Disulfides; D015870:Gene Expression; D020869:Gene Expression Profiling; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014101:Torpedo / Q000235:genetics; D017187:Tylenchida / Q000201:enzymology*
chemical_list: D004220:Disulfides; D000110:Acetylcholinesterase