title: Mitochondria-localized phospholipase A2, AoPlaA, in Aspergillus oryzae displays phosphatidylethanolamine-specific activity and is involved in the maintenance of mitochondrial phospholipid composition.
abstract: In mammals, cytosolic phospholipases A2(cPLA2s) play important physiological roles by releasing arachidonic acid, a precursor for bioactive lipid mediators, from the biological membranes. In contrast, fungal cPLA2-like proteins are much less characterized and their roles have remained elusive. AoPlaA is a cPLA2-like protein in the filamentous fungus Aspergillus oryzae which, unlike mammalian cPLA2, localizes to mitochondria. In this study, we investigated the biochemical and physiological functions of AoPlaA. Recombinant AoPlaA produced in E. coli displayed Ca2+-independent lipolytic activity. Mass spectrometry analysis demonstrated that AoPlaA displayed PLA2activity to phosphatidylethanolamine (PE), but not to other phospholipids, and generated 1-acylated lysoPE. Catalytic site mutants of AoPlaA displayed almost no or largely reduced activity to PE. Consistent with PE-specific activity of AoPlaA, AoplaA-overexpressing strain showed decreased PE content in the mitochondrial fraction. In contrast, AoplaA-disruption strain displayed increased content of cardiolipin. AoplaA-overexpressing strain, but not its counterparts overexpressing the catalytic site mutants, exhibited retarded growth at low temperature, possibly because of the impairment of the mitochondrial function caused by excess degradation of PE. These results suggest that AoPlaA is a novel PE-specific PLA2that plays a regulatory role in the maintenance of mitochondrial phospholipid composition.
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kotani
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Izawa
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Komai
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Takayanagi
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: arioka@mail.ecc.u-tokyo.ac.jp.
authors.forename: Manabu
authors.initials: M
authors.lastname: Arioka
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology* / Q000254:growth & development; D004926:Escherichia coli / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D054467:Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D010714:Phosphatidylethanolamines; D010743:Phospholipids; D011994:Recombinant Proteins; C483858:phosphatidylethanolamine; D054467:Phospholipases A2
keywords: Aspergillus oryzae; Cytosolic phospholipase A(2); Mitochondria; Phosphatidylethanolamine