Structural basis of actin filament capping at the barbed-end: A cryo-electron microscopy study

Akihiro Narita, Shuichi Takeda, Atsuko Yamashita, Yuichiro Maéda

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83 Citations (Scopus)


The intracellular distribution and migration of many protein complexes and organelles is regulated by the dynamics of the actin filament. Many actin filament end-binding proteins play crucial roles in actin dynamics, since polymerization and depolymerization of actin protomers occur only at the filament ends. We present here an EM structure of the complex of the actin filament and hetero-dimeric capping protein (CP) bound to the barbed-end at 23 Å resolution, by applying a newly developed methods of image analysis to cryo-electron micrographs. This structure was fitted by the crystal structure of CP and the proposed actin filament structure, allowing us to construct a model that depicts two major binding regions between CP and the barbed-end. This binding scheme accounted for the results of newly performed and previously published mutation experiments, and led us to propose a two-step binding model. This is the first determination of an actin filament end structure.

Original languageEnglish
Pages (from-to)5626-5633
Number of pages8
JournalEMBO Journal
Issue number23
Publication statusPublished - Nov 29 2006
Externally publishedYes


  • Actin capping
  • Actin filament
  • Capping protein
  • Electron cryo-microscopy
  • Single particle analysis

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)


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