Molecular basis of actin reorganization promoted by binding of enterohaemorrhagic Escherichia coli EspB to α-catenin

• Published in: The FEBS journal Vol. 275; no. 24; pp. 6260 - 6267
• Main Authors: Hamaguchi, Mitsuhide, Hamada, Daizo, Suzuki, Kayo N, Sakata, Ikuhiro, Yanagihara, Itaru
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.12.2008; Blackwell Publishing Ltd
• Subjects: actin branching; actin bundling; Actins - chemistry; Actins - isolation & purification; Actins - metabolism; Actins - ultrastructure; alpha Catenin - chemistry; alpha Catenin - isolation & purification; alpha Catenin - metabolism; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - isolation & purification; Bacterial Outer Membrane Proteins - metabolism; Binding Sites; Cadherins - chemistry; Cadherins - metabolism; co-sedimentation; Enterohemorrhagic Escherichia coli - metabolism; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - isolation & purification; Escherichia coli Proteins - metabolism; Escherichia coli Proteins - ultrastructure; Gram-Negative Bacteria - metabolism; Kinetics; Microscopy, Electron; Protein Binding; pyrene-actin polymerization; Type III secretion system; Vinculin - chemistry; Vinculin - metabolism
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/j.1742-4658.2008.06750.x

EspB is a multifunctional protein associated with the type III secretion system of enterohaemorrhagic Escherichia coli, and interacts with various biomolecules including α-catenin in the host cell. The binding of EspB to α-catenin is thought be involved in actin reorganization during bacterial infection, although the precise mechanism of this phenomenon is still unclear. Recent research shows that dimerization of α-catenin dissociates it from E-cadherin/β-catenin/α-catenin complexes, and that the dimer suppresses Arp2/3-mediated actin branching or polymerization. These results inspired us to evaluate the effect of EspB on the functions of α-catenin. Based on a series of in vitro biochemical approaches, including pull-down, co-sedimentation and pyrene-actin polymerization assays combined with transmission electron microscopy, we conclude that EspB promotes all the functions of dimeric α-catenin described above. These results clarified the molecular basis of reorganization of actin filaments during infection with enterohaemorrhagic Escherichia coli.