Japan Agency for Medical Research and Development (AMED)
JP21gm161003
日本
Japan Science and Technology
JPMJFR214K
日本
Japan Science and Technology
JPMJMS2024
日本
引用
ジャーナル: iScience / 年: 2025 タイトル: Cryo-ET of actin cytoskeleton and membrane structure in lamellipodia formation using optogenetics. 著者: Hironori Inaba / Tsuyoshi Imasaki / Kazuhiro Aoyama / Shogo Yoshihara / Hiroko Takazaki / Takayuki Kato / Hidemasa Goto / Kaoru Mitsuoka / Ryo Nitta / Takao Nakata / 要旨: Lamellipodia are sheet-like protrusions essential for cell migration and endocytosis, but their ultrastructural dynamics remain poorly understood because conventional electron microscopy lacks ...Lamellipodia are sheet-like protrusions essential for cell migration and endocytosis, but their ultrastructural dynamics remain poorly understood because conventional electron microscopy lacks temporal resolution. Here, we combined optogenetics with cryo-electron tomography (cryo-ET) to visualize the actin cytoskeleton and membrane structures during lamellipodia formation with temporal precision. Using photoactivatable-Rac1 (PA-Rac1) in COS-7 cells, we induced lamellipodia formation with a 2-min blue light irradiation, rapidly vitrified samples, and analyzed their ultrastructure with cryo-ET. We obtained 16 tomograms of lamellipodia at different degrees of extension from three cells. These revealed small protrusions with unbundled actin filaments, "mini filopodia" composed of short, bundled actin filaments at the leading edge, and actin bundles running nearly parallel to the leading edge within inner regions of lamellipodia, suggesting dynamic reorganizations of the actin cytoskeleton. This approach provides a powerful framework for elucidating the ultrastructural dynamics of cellular processes with precise temporal control.