title: Mutation in keratin 18 induces mitochondrial fragmentation in liver-derived epithelial cells.
abstract: Microtubules (MTs) and microfilaments (MFs) are known to modulate mitochondrial morphology, distribution and function. However, little is known evidence about the role of intermediate filaments (IFs) in modulating mitochondria except desmin. To investigate whether or not the IFs regulate mitochondrial morphology, distribution, and function, we manipulated the IFs of cultured epithelial cells to express a mutant keratin 18 (K18). In contrast to the filamentous expression of wild K18, mutant K18 induced aggregation of K8/18, showing no fine IF network in the cells. In mutant K18-transfected cells, the mitochondria were fragmented into small spheroids, although they were observed as mitochondrial fibers in un-transfected or wild K18-transfected cells. Fluorescence recovery after photobleaching of fluorescence-labeled mitochondria was markedly less in the mutant K18-transfected cells, although a significant recovery was confirmed in wild K18-transfected cells. These findings suggest that the IFs are important for the maintenance of normal mitochondrial structures.
authors.affiliation: Division of Gastroenterology, Department of Medicine and Research Center for Innovative Cancer Therapy, Kurume University School of Medicine, 67 Asahi-Machi, Kurume 830-0011, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kumemura
authors.forename: Masaru
authors.initials: M
authors.lastname: Harada
authors.forename: Chikatoshi
authors.initials: C
authors.lastname: Yanagimoto
authors.forename: Hironori
authors.initials: H
authors.lastname: Koga
authors.forename: Takumi
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Hanada
authors.forename: Eitaro
authors.initials: E
authors.lastname: Taniguchi
authors.forename: Takato
authors.initials: T
authors.lastname: Ueno
authors.forename: Michio
authors.initials: M
authors.lastname: Sata
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology*; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D053538:Keratin-18 / Q000235:genetics*; D008107:Liver Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008930:Mitochondria, Liver / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009154:Mutation; D014162:Transfection
chemical_list: D005456:Fluorescent Dyes; D053538:Keratin-18