title: Peptidylarginine deiminase modulates the physiological roles of enolase via citrullination: links between altered multifunction of enolase and neurodegenerative diseases.
abstract: The citrullination of enolase by PAD (peptidylarginine deiminase) has emerged as an important post-translational modification in human disorders; however, the physiological function of citrullination remains unknown. In the present study, we report that citrullination diversely regulates the biological functions of ENO1 (α-enolase) and NSE (neuron-specific enolase). We developed three mouse IgG1 monoclonal antibodies with specificity to the following: (i) citrullination of Arg9 of ENO1 [ENO1Cit9; anti-CE1 (citrullinated enolase 1) antibody]; (ii) citrullination of Arg9 in ENO1 and NSE (ENO1Cit9/NSECit9; anti-CE1/2 antibody); and (iii) citrullination of Arg429 of NSE (NSECit429; anti-CE2 antibody). Regardless of the total protein expression level, the levels of ENO1Cit9 and NSECit429 were elevated, and their immunoreactivities were also increased in cortical neuronal cells or around blood vessels in the frontal cortex of patients with sporadic Creutzfeldt-Jakob disease and Alzheimer's disease compared with controls. In a time- and dose-dependent manner, PAD negatively regulated enolase activity via citrullination, and enolase in diseased patients was more inactive than in controls. Interestingly, the citrullination of enolase effectively promoted its proteolytic degradation by Ca2+-dependent calpain-1, and leupeptin (calpain inhibitor I) abrogated this degradation. Surprisingly, using an affinity assay, the citrullination of enolase enhanced its plasminogen-binding affinity, which was blocked by the lysine analogue ϵ-aminocaproic acid. These findings suggest that PAD-mediated citrullination regulates the diverse physiological activities of enolase and that CE may be a candidate diagnostic/prognostic factor for degenerative diseases.
authors.affiliation: Ilsong Institute of Life Science, Hallym University, 1605-4 Gwanyang-Dong, Dongan-Gu, Anyang, Gyeonggi-do 432-060, Republic of Korea.
authors.forename: Byungki
authors.initials: B
authors.lastname: Jang
authors.forename: Yong-Chul
authors.initials: YC
authors.lastname: Jeon
authors.forename: Jin-Kyu
authors.initials: JK
authors.lastname: Choi
authors.forename: Mira
authors.initials: M
authors.lastname: Park
authors.forename: Jae-Il
authors.initials: JI
authors.lastname: Kim
authors.forename: Akihito
authors.initials: A
authors.lastname: Ishigami
authors.forename: Naoki
authors.initials: N
authors.lastname: Maruyama
authors.forename: Richard I
authors.initials: RI
authors.lastname: Carp
authors.forename: Yong-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Eun-Kyoung
authors.initials: EK
authors.lastname: Choi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism* / Q000473:pathology; D015119:Aminocaproic Acid / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D014408:Biomarkers, Tumor / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D016022:Case-Control Studies; D002956:Citrulline / Q000378:metabolism*; D007562:Creutzfeldt-Jakob Syndrome / Q000378:metabolism* / Q000473:pathology; D004268:DNA-Binding Proteins / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism; D006801:Humans; D006867:Hydrolases / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000276:immunology; D010751:Phosphopyruvate Hydratase / Q000276:immunology / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D000076342:Protein-Arginine Deiminases; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C533270:NSMCE1 protein, human; D010446:Peptide Fragments; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins; D002956:Citrulline; D010958:Plasminogen; D006867:Hydrolases; D000076342:Protein-Arginine Deiminases; C095157:ENO1 protein, human; D010751:Phosphopyruvate Hydratase; D015119:Aminocaproic Acid