title: Inherited and acquired interactions between ACHE and PON1 polymorphisms modulate plasma acetylcholinesterase and paraoxonase activities.
abstract: The 5.5 Mb chromosome 7q21-22 ACHE/PON1 locus harbours the ACHE gene encoding the acetylcholine hydrolyzing, organophosphate (OP)-inhibitable acetylcholinesterase protein and the paraoxonase gene PON1, yielding the OP-hydrolyzing PON1 enzyme which also displays arylesterase activity. In search of inherited and acquired ACHE-PON1 interactions we genotyped seven polymorphic sites and determined the hydrolytic activities of the corresponding plasma enzymes and of the AChE-homologous butyrylcholinesetrase (BChE) in 157 healthy Israelis. AChE, arylesterase, BChE and paraoxonase activities in plasma displayed 5.4-, 6.5-, 7.2- and 15.5-fold variability, respectively, with genotype-specific differences between carriers of distinct compound polymorphisms. AChE, BChE and arylesterase but not paraoxonase activity increased with age, depending on leucine at PON1 position 55. In contrast, carriers of PON1 M55 displayed decreased arylesterase activity independent of the - 108 promoter polymorphism. Predicted structural consequences of the PON1 L55M substitution demonstrated spatial shifts in adjacent residues. Molecular modelling showed substrate interactions with the enzyme variants, explaining the changes in substrate specificity induced by the Q192R substitution. Intriguingly, PON1, but not BChE or arylesterase, activities displayed inverse association with AChE activity. Our findings demonstrate that polymorphism(s) in the adjacent PON1 and ACHE genes affect each other's expression, predicting for carriers of biochemically debilitating ACHE/PON1 polymorphisms adverse genome-environment interactions.
authors.affiliation: Department of Biological Chemistry, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
authors.forename: Boris
authors.initials: B
authors.lastname: Bryk
authors.forename: Liat
authors.initials: L
authors.lastname: BenMoyal-Segal
authors.forename: Erez
authors.initials: E
authors.lastname: Podoly
authors.forename: Oded
authors.initials: O
authors.lastname: Livnah
authors.forename: Arik
authors.initials: A
authors.lastname: Eisenkraft
authors.forename: Shai
authors.initials: S
authors.lastname: Luria
authors.forename: Amir
authors.initials: A
authors.lastname: Cohen
authors.forename: Yoav
authors.initials: Y
authors.lastname: Yehezkelli
authors.forename: Ariel
authors.initials: A
authors.lastname: Hourvitz
authors.forename: Hermona
authors.initials: H
authors.lastname: Soreq
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D043303:Aryldialkylphosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002091:Butyrylcholinesterase / Q000097:blood / Q000737:chemistry / Q000235:genetics; D019556:COS Cells; D002265:Carboxylic Ester Hydrolases / Q000097:blood; D002522:Chlorocebus aethiops; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
chemical_list: D012333:RNA, Messenger; D002265:Carboxylic Ester Hydrolases; C019734:arylesterase; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human