Direct interaction of the C-terminal domain of alpha-catenin and F-actin is necessary for stabilized cell-cell adhesion.
Alpha-catenin functions to anchor adherens junctions to the filamentous actin (F-actin) cytoskeleton, through direct and indirect binding mechanisms. When truncated at amino acid 865, alpha-catenin exhibited a markedly reduced F-actin binding affinity compared to wild-type. Expression of the truncated mutant in the alpha-catenin deficient colon carcinoma cell line, Clone A, could not restore an adhesive phenotype when compared. Furthermore, the truncated alpha-catenin fusion protein failed to concentrate at sites of cell-cell contact, to promote morphological changes associated with epithelial monolayers, and to stimulate resistance to shearing forces in a hanging drop aggregation assay. Subsequent attempts to isolate single residues governing the direct F-actin interaction, using neutralizing charge or reverse charge mutations of basic residues within a homology modeled alpha-catenin C-terminal 5-helix bundle, had no effect on F-actin cosedimentation. We conclude that direct attachment of alpha-catenin to F-actin is required to promote cadherin-mediated contact formation and strong cell-cell adhesive states.
Pappas
Derek J
DJ
The Department of Cell Biology, Yale University, New Haven, Connecticut 06520-8023, USA.
Rimm
David L
DL
D000199:Actins / Q000378:metabolism*; D002448:Cell Adhesion; D002449:Cell Aggregation; D045744:Cell Line, Tumor; D004252:DNA Mutational Analysis; D006801:Humans; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D040681:Structural Homology, Protein; D014407:Tumor Cells, Cultured; D051178:alpha Catenin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D011993:Recombinant Fusion Proteins; D051178:alpha Catenin