Biochemical and structural analysis of α-catenin in cell-cell contacts

Sabine Pokutta, Frauke Drees, Soichiro Yamada, W. James Nelson, William I. Weis

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

Cadherins are transmembrane adhesion molecules that mediate homotypic cell-cell contact. In adherens junctions, the cytoplasmic domain of cadherins is functionally linked to the actin cytoskeleton through a series of proteins known as catenins. E-cadherin binds to β-catenin, which in turn binds to α-catenin to form a ternary complex. α-Catenin also binds to actin, and it was assumed previously that α-catenin links the cadherin-catenin complex to actin. However, biochemical, structural and live-cell imaging studies of the cadherin-catenin complex and its interaction with actin show that binding of β-catenin to α-catenin prevents the latter from binding to actin. Biochemical and structural data indicate that α-catenin acts as an allosteric protein whose conformation and activity changes depending on whether or not it is bound to β-catenin. Initial contacts between cells occur on dynamic lamellipodia formed by polymerization of branched actin networks, a process controlled by the Arp2/3 (actin-related protein 2/3) complex. α-Catenin can suppress the activity of Arp2/3 by competing for actin filaments. These findings lead to a model for adherens junction formation in which clustering of the cadherin-β-catenin complex recruits high levels of α-catenin that can suppress the Arp2/3 complex, leading to cessation of lamellipodial movement and formation of a stable contact. Thus α-catenin appears to play a central role in cell-cell contact formation.

Original languageEnglish (US)
Pages (from-to)141-147
Number of pages7
JournalBiochemical Society Transactions
Volume36
Issue number2
DOIs
StatePublished - Apr 2008
Externally publishedYes

Keywords

  • Actin
  • Actin-related protein 2/3 complex (Arp2/3 complex)
  • Adherens junction
  • Cadherin
  • Catenin
  • Cell adhesion

ASJC Scopus subject areas

  • Biochemistry

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