イチハラ　アツヒロ   ICHIHARA Atsuhiro   市原　淳弘    所属   医学部 医学科（東京女子医科大学病院）    職種   教授・基幹分野長
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Vacuolar ATPase in phagosome-lysosome fusion.
掲載誌名	正式名：The Journal of biological chemistry 略　 称：J Biol Chem ISSNコード：1083351X(Electronic)00219258(Linking)
巻・号・頁	290(22),pp.14166-80
著者・共著者	Kissing Sandra†, Hermsen Christina, Repnik Urska, Nesset Cecilie Kåsi, von Bargen Kristine, Griffiths Gareth, Ichihara Atsuhiro, Lee Beth S, Schwake Michael, De Brabander Jef, Haas Albert, Saftig Paul
発行年月	2015/05
概要	The vacuolar H(+)-ATPase (v-ATPase) complex is instrumental in establishing and maintaining acidification of some cellular compartments, thereby ensuring their functionality. Recently it has been proposed that the transmembrane V0 sector of v-ATPase and its a-subunits promote membrane fusion in the endocytic and exocytic pathways independent of their acidification functions. Here, we tested if such a proton-pumping independent role of v-ATPase also applies to phagosome-lysosome fusion. Surprisingly, endo(lyso)somes in mouse embryonic fibroblasts lacking the V0 a3 subunit of the v-ATPase acidified normally, and endosome and lysosome marker proteins were recruited to phagosomes with similar kinetics in the presence or absence of the a3 subunit. Further experiments used macrophages with a knockdown of v-ATPase accessory protein 2 (ATP6AP2) expression, resulting in a strongly reduced level of the V0 sector of the v-ATPase. However, acidification appeared undisturbed, and fusion between latex bead-containing phagosomes and lysosomes, as analyzed by electron microscopy, was even slightly enhanced, as was killing of non-pathogenic bacteria by V0 mutant macrophages. Pharmacologically neutralized lysosome pH did not affect maturation of phagosomes in mouse embryonic cells or macrophages. Finally, locking the two large parts of the v-ATPase complex together by the drug saliphenylhalamide A did not inhibit in vitro and in cellulo fusion of phagosomes with lysosomes. Hence, our data do not suggest a fusion-promoting role of the v-ATPase in the formation of phagolysosomes.
DOI	10.1074/jbc.M114.628891
PMID	25903133