title: Three-dimensional nanometry of vesicle transport in living cells using dual-focus imaging optics.
abstract: Dual-focus imaging optics for three-dimensional tracking of individual quantum dots has been developed to study the molecular mechanisms of motor proteins in cells. The new system has a high spatial and temporal precision, 2 nm in the x-y sample plane and 5 nm along the z-axis at a frame time of 2 ms. Three-dimensional positions of the vesicles labeled with quantum dots were detected in living cells. Vesicles were transported on the microtubules using 8-nm steps towards the nucleus. The steps had fluctuation of approximately 20 nm which were perpendicular to the axis of the microtubule but with the constant distance from the microtubule. The most of perpendicular movement was not synchronized with the 8-nm steps, indicating that dynein moved on microtubules without changing the protofilaments. When the vesicles changed their direction of movement toward the cell membrane, they moved perpendicular with the constant distance from the microtubule. The present method is powerful tool to investigate three dimensional movement of molecules in cells with nanometer and millisecond accuracy.
authors.affiliation: Biomedical and Engineering Research Organization, Tohoku University, Sendai, Miyagi 980-8579, Japan.
authors.forename: Tomonobu M
authors.initials: TM
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Gonda
authors.forename: Hideo
authors.initials: H
authors.lastname: Higuchi
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000648:ultrastructure; D045744:Cell Line, Tumor; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D008856:Microscopy, Fluorescence / Q000295:instrumentation* / Q000379:methods; D020409:Molecular Motor Proteins / Q000378:metabolism* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D055095:Optics and Photonics / Q000295:instrumentation*; D022161:Transport Vesicles / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D020409:Molecular Motor Proteins