title: Fusion of mitochondria in tobacco suspension cultured cells is dependent on the cellular ATP level but not on actin polymerization.
abstract: Mitochondria in plant cells undergo fusion and fission frequently. Although the mechanisms and proteins of mitochondrial fusion are well known in yeast and mammalian cells, they remain poorly understood in plant cells. To clarify the physiological requirements for plant mitochondrial fusion, we investigated the fusion frequency of mitochondria in tobacco cultured cells using the photoconvertible fluorescent protein Kaede and some physiological inhibitors. The latter included two uncouplers, 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of mitochondrial ATP synthase, oligomycin, and an actin polymerization inhibitor, latrunculin B (Lat B). The frequency of mitochondrial fusion was clearly reduced by DNP, CCCP and oligomycin, but not by Lat B, although Lat B severely inhibited mitochondrial movement. Moreover, DNP, CCCP and oligomycin evidently lowered the cellular ATP levels. These results indicate that plant mitochondrial fusion depends on the cellular ATP level, but not on actin polymerization.
authors.affiliation: Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Kairo
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: Masaru
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Mikio
authors.initials: M
authors.lastname: Nakazono
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Arimura
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Tsutsumi
mesh_terms: D019297:2,4-Dinitrophenol / Q000494:pharmacology; D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002478:Cells, Cultured; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000502:physiology*; D051336:Mitochondrial Membranes / Q000502:physiology*; D009840:Oligomycins / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000378:metabolism; D055503:Protein Multimerization; D053778:Thiazolidines / Q000494:pharmacology; D014026:Nicotiana / Q000378:metabolism*
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009840:Oligomycins; D053778:Thiazolidines; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; C037068:latrunculin B; D019297:2,4-Dinitrophenol