Vinculin regulates cell-surface E-cadherin expression by binding to beta-catenin.
Vinculin was identified as a component of adherens junctions 30 years ago, yet its function there remains elusive. Deletion studies are consistent with the idea that vinculin is important for the organization of cell-cell junctions. However, this approach removes vinculin from both cell-matrix and cell-cell adhesions, making it impossible to distinguish its contribution at each site. To define the role of vinculin in cell-cell junctions, we established a powerful short hairpin-RNA-based knockdown/substitution model system that perturbs vinculin preferentially at sites of cell-cell adhesion. When this system was applied to epithelial cells, cell morphology was altered, and cadherin-dependent adhesion was reduced. These defects resulted from impaired E-cadherin cell-surface expression. We have investigated the mechanism for the effects of vinculin and found that the reduced surface E-cadherin expression could be rescued by introduction of vinculin, but not of a vinculin A50I substitution mutant that is defective for beta-catenin binding. These findings suggest that an interaction between beta-catenin and vinculin is crucial for stabilizing E-cadherin at the cell surface. This was confirmed by analyzing a beta-catenin mutant that fails to bind vinculin. Thus, our study identifies vinculin as a novel regulator of E-cadherin function and provides important new insight into the dynamic regulation of adherens junctions.
Peng
Xiao
X
Department of Biochemistry, University of Iowa Roy J. Carver College of Medicine, Iowa City, IA 52242, USA.
Cuff
Laura E
LE
Lawton
Cort D
CD
DeMali
Kris A
KA
D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D002645:Chickens; D005260:Female; D006801:Humans; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016596:Vinculin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
D030161:Avian Proteins; C495270:CTNNB1 protein, human; D015820:Cadherins; D011993:Recombinant Fusion Proteins; C035689:VCL protein, Gallus gallus; C488955:VCL protein, human; D051176:beta Catenin; D016596:Vinculin