Crystal structure of CapZ: Structural basis for actin filament barbed end capping

Atsuko Yamashita, Kayo Maeda, Yuichiro Maéda

Research output: Contribution to journalArticlepeer-review

124 Citations (Scopus)


Capping protein, a heterodimeric protein composed of α and β subunits, is a key cellular component regulating actin filament assembly and organization. It binds to the barbed ends of the filaments and works as a 'cap' by preventing the addition and loss of actin monomers at the end. Here we describe the crystal structure of the chicken sarcomeric capping protein CapZ at 2.1 Å resolution. The structure shows a striking resemblance between the α and β subunits, so that the entire molecule has a pseudo 2-fold rotational symmetry. CapZ has a pair of mobile extensions for actin binding, one of which also provides concomitant binding to another protein for the actin filament targeting. The mobile extensions probably form flexible links to the end of the actin filament with a pseudo 21 helical symmetry, enabling the docking of the two in a symmetry mismatch.

Original languageEnglish
Pages (from-to)1529-1538
Number of pages10
JournalEMBO Journal
Issue number7
Publication statusPublished - Apr 1 2003
Externally publishedYes


  • 2-fold rotational symmetry
  • Actin filament
  • CapZ
  • Capping protein
  • Cytoskeleton

ASJC Scopus subject areas

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


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