title: Probing in vivo dynamics of mitochondria and cortical actin networks using high-speed atomic force/fluorescence microscopy.
abstract: The dynamics of the cell membrane and submembrane structures are closely linked, facilitating various cellular activities. Although cell surface research and cortical actin studies have shown independent mechanisms for the cell membrane and the actin network, it has been difficult to obtain a comprehensive understanding of the dynamics of these structures in live cells. Here, we used a combined atomic force/optical microscope system to analyze membrane-based cellular events at nanometer-scale resolution in live cells. Imaging the COS-7 cell surface showed detailed structural properties of membrane invagination events corresponding to endocytosis and exocytosis. In addition, the movement of mitochondria and the spatiotemporal dynamics of the cortical F-actin network were directly visualized in vivo. Cortical actin microdomains with sizes ranging from 1.7×10(4) to 1.4×10(5) nm2 were dynamically rearranged by newly appearing actin filaments, which sometimes accompanied membrane invaginations, suggesting that these events are integrated with the dynamic regulation of submembrane organizations maintained by actin turnovers. These results provide novel insights into the structural aspects of the entire cell membrane machinery which can be visualized with high temporal and spatial resolution.
authors.affiliation: Graduate School of Biostudies, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Yoshida
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Sakai
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Uekusa
authors.forename: Katashi
authors.initials: K
authors.lastname: Deguchi
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Gilmore
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kumeta
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ito
authors.forename: Kunio
authors.initials: K
authors.lastname: Takeyasu
mesh_terms: D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D019556:COS Cells / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure*; D004705:Endocytosis; D005089:Exocytosis; D018625:Microscopy, Atomic Force / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D063154:Mitochondrial Dynamics
chemical_list: D000199:Actins