title: Role of acylamino acid-releasing enzyme/oxidized protein hydrolase in sustaining homeostasis of the cytoplasmic antioxidative system.
abstract: Acylamino acid-releasing enzyme/oxidized protein hydrolase (AARE/OPH) has been biochemically demonstrated to be a bifunctional protease that has exopeptidase activity against Nα-acylated peptides and endopeptidase activity against oxidized and glycated proteins; however, its physiological role remains unknown. In this study, to determine its physiological significance, we produced AARE/OPH-overexpressing and -suppressed plants and assessed the biological impacts of AARE/OPH. The subcellular localization of Arabidopsis AARE/OPH was found to be cytoplasmic and nuclear by transient expression analysis of tdTomato-fused Arabidopsis AARE/OPH. Overexpression of AARE/OPH exhibited no apparent effect on the level of oxidized proteins because wild types probably have inherently high AARE/OPH activity. Through RNAi gene suppressing, we successfully produced AARE/OPH-suppressed Arabidopsis plants (aare) that exhibited almost no AARE activity. In the aare plant, electrolyte leakage by methyl viologen treatment was enhanced compared to that of non-transformant plants, suggesting that the plasma membranes of aare easily suffered oxidative damage, probably as a result of deterioration of the cytoplasmic antioxidative system. Correspondingly, proteomic analysis revealed that the aare plant accumulated a number of oxidized proteins including cytoplasmic antioxidant enzymes. On the basis of these results, we concluded that AARE/OPH plays a homeostatic role in sustaining the cytoplasmic antioxidative system.
authors.affiliation: Faculty of Agriculture, Tottori University, Koyama-cho Minami 4-101, Tottori, 680-8553, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Sawako
authors.initials: S
authors.lastname: Sumi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D000215:Acylation; D000595:Amino Acid Sequence; D000975:Antioxidants / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology / Q000378:metabolism; D015870:Gene Expression / Q000502:physiology; D006706:Homeostasis / Q000502:physiology; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D010447:Peptide Hydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D040901:Proteomics; D034622:RNA Interference; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000502:physiology
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D010447:Peptide Hydrolases; C038220:acylaminoacyl-peptidase