Coronin-1A Stabilizes F-Actin by Bridging Adjacent Actin Protomers and Stapling Opposite Strands of the Actin Filament

Vitold E. Galkin, Albina Orlova, William Brieher, Hao Yuan Kueh, Timothy J. Mitchison, Edward H. Egelman

Research output: Contribution to journalArticlepeer-review

Abstract

Coronins are F-actin-binding proteins that are involved, in concert with Arp2/3, Aip1, and ADF/cofilin, in rearrangements of the actin cytoskeleton. An understanding of coronin function has been hampered by the absence of any structural data on its interaction with actin. Using electron microscopy and three-dimensional reconstruction, we show that coronin-1A binds to three protomers in F-actin simultaneously: it bridges subdomain 1 and subdomain 2 of two adjacent actin subunits along the same long-pitch strand, and it staples subdomain 1 and subdomain 4 of two actin protomers on different strands. Such a mode of binding explains how coronin can stabilize actin filaments in vitro. In addition, we show which residues of F-actin may participate in the interaction with coronin-1A. Human nebulin and Xin, as well as Salmonella invasion protein A, use a similar mechanism to stabilize actin filaments. We suggest that the stapling of subdomain 1 and subdomain 4 of two actin protomers on different strands is a common mechanism for F-actin stabilization utilized by many actin-binding proteins that have no homology.

Original languageEnglish (US)
Pages (from-to)607-613
Number of pages7
JournalJournal of Molecular Biology
Volume376
Issue number3
DOIs
StatePublished - Feb 22 2008
Externally publishedYes

Keywords

  • actin binding proteins
  • electron microscopy
  • image analysis

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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