title: STED super-resolution imaging of mitochondria labeled with TMRM in living cells.
abstract: We applied stimulated emission depletion (STED) imaging with subdiffraction resolution to submitochondrial structures in mitochondria. Their shapes depend on both a cell's type and its physiological state. Staining with a cationic fluorescent dye, tetramethylrhodamine methyl ester (TMRM), unveiled intriguing details of lamellar structure, consisting of rapidly changeable, curtain-like formations. The TMRM-positive structure colocalized with neither proteins in the matrix nor on the outer membrane, but partially localized with the nucleoid. Suppression of a component in the mitochondrial contact site disrupted the lamellar TMRM-positive structure. Uncoupling of the oxidative phosphorylation system released TMRM from the inner membrane without any alteration in the matrix structure. STED images further showed that complexes of the electron transport chain are located on the surface of TMRM-positive structures. The approach presented here provides novel insights into the in vivo nature of submitochondrial structures, and can be used for further functional investigations of these complex structures.
authors.affiliation: Biological Process of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan; Division of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Ishigaki
authors.affiliation: Biological Process of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
authors.forename: Masumi
authors.initials: M
authors.lastname: Iketani
authors.affiliation: Department of Clinical Laboratory, Tokyo Metropolitan Geriatric Hospital, Itabashi-ku, Tokyo 173-0015, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Sugaya
authors.affiliation: Biological Process of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Department of Clinical Laboratory, Tokyo Metropolitan Geriatric Hospital, Itabashi-ku, Tokyo 173-0015, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Division of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Seisuke
authors.initials: S
authors.lastname: Hattori
authors.affiliation: Biological Process of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan. Electronic address: iohsawa@tmig.or.jp.
authors.forename: Ikuroh
authors.initials: I
authors.lastname: Ohsawa
mesh_terms: D006801:Humans; D008853:Microscopy / Q000379:methods*; D008928:Mitochondria / Q000737:chemistry* / Q000648:ultrastructure*; D012235:Rhodamines / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D012235:Rhodamines; C401833:tetramethylrhodamine methyl ester
keywords: Cationic fluorescent dye; Mitochondrial inner membrane; Mitochondrial membrane potential; Oxidative phosphorylation system