title: Natriuretic peptide pharmacogenetics: membrane metallo-endopeptidase (MME): common gene sequence variation, functional characterization and degradation.
abstract: Membrane metallo-endopeptidase (MME), also known as neutral endopeptidase 24.11 (EC 3.4.24.11), is involved in the metabolism of natriuretic peptides that play a key role in modulating cardiac structure and function. Common genetic variation in MME has not been addressed by resequencing the gene using DNA from different ethnic populations. We set out to identify and functionally characterize common genetic variation in MME in three ethnic groups. DNA samples from 96 European-American, 96 African-American, and 96 Han Chinese-American healthy subjects were used to resequence MME. Ninety polymorphisms, 65 novel, were identified, including 8 nonsynonymous single nucleotide polymorphisms (nsSNPs). Expression constructs for the nsSNPs were created and COS-1 cells were transfected with constructs for wild type (WT) and variant allozymes. Recombinant proteins were analyzed by quantitative Western blot analysis and by a one-step fluorometric assay. A significant reduction in enzyme activity (21% of WT) and immunoreactive protein (29% of WT) for the Val73 variant allozyme was observed. Proteasome-mediated degradation and autophagy participated in the degradation of this variant allozyme. The chaperone proteins, BiP and GRP94, were upregulated after transfection with Val73 MME, suggesting protein misfolding, compatible with conclusions based on the MME X-ray crystal structure. Multiple novel polymorphisms of MME were identified in three ethnic groups. The Val73 variant allozyme displayed a significant decrease in MME protein quantity and activity, with degradation mediated by both proteasome and autophagy pathways. This polymorphism could have a significant effect on the metabolism of natriuretic peptides.
authors.affiliation: Division of Cardiovascular Diseases and Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA. pereira.naveen@mayo.edu
authors.forename: Naveen L
authors.initials: NL
authors.lastname: Pereira
authors.forename: Pinar
authors.initials: P
authors.lastname: Aksoy
authors.forename: Irene
authors.initials: I
authors.lastname: Moon
authors.forename: Yi
authors.initials: Y
authors.lastname: Peng
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Redfield
authors.forename: John C
authors.initials: JC
authors.lastname: Burnett
authors.forename: Eric D
authors.initials: ED
authors.lastname: Wieben
authors.forename: Vivien C
authors.initials: VC
authors.lastname: Yee
authors.forename: Richard M
authors.initials: RM
authors.lastname: Weinshilboum
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics*; D001343:Autophagy; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D014644:Genetic Variation; D023281:Genomics; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D015810:Linkage Disequilibrium / Q000235:genetics; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000378:metabolism; D015260:Neprilysin / Q000235:genetics* / Q000378:metabolism*; D010597:Pharmacogenetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017422:Sequence Analysis, DNA; D014633:Valine / Q000235:genetics
chemical_list: D007527:Isoenzymes; D018832:Molecular Chaperones; D009320:Atrial Natriuretic Factor; D015260:Neprilysin; D046988:Proteasome Endopeptidase Complex; D014633:Valine