Interaction of alpha-actinin with the cadherin/catenin cell-cell adhesion complex via alpha-catenin.
Cadherins are Ca(2+)-dependent, cell surface glycoproteins involved in cell-cell adhesion. Extracellularly, transmembrane cadherins such as E-, P-, and N-cadherin self-associate, while intracellularly they interact indirectly with the actin-based cytoskeleton. Several intracellular proteins termed catenins, including alpha-catenin, beta-catenin, and plakoglobin, are tightly associated with these cadherins and serve to link them to the cytoskeleton. Here, we present evidence that in fibroblasts alpha-actinin, but not vinculin, colocalizes extensively with the N-cadherin/catenin complex. This is in contrast to epithelial cells where both cytoskeletal proteins colocalize extensively with E-cadherin and catenins. We further show that alpha-actinin, but not vinculin, coimmunoprecipitates specifically with alpha- and beta-catenin from N- and E-cadherin-expressing cells, but only if alpha-catenin is present. Moreover, we show that alpha-actinin coimmunoprecipitates with the N-cadherin/catenin complex in an actin-independent manner. We therefore propose that cadherin/catenin complexes are linked to the actin cytoskeleton via a direct association between alpha-actinin and alpha-catenin.
Knudsen
K A
KA
Lankenau Medical Research Center, Wynnewood, Pennsylvania 19096, USA.
Soler
A P
AP
Johnson
K R
KR
Wheelock
M J
MJ
D000185:Actinin / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D002448:Cell Adhesion; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003599:Cytoskeleton / Q000648:ultrastructure; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D006801:Humans; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D011233:Precipitin Tests; D016596:Vinculin / Q000378:metabolism; D051178:alpha Catenin
C495273:CTNNA1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D046911:Macromolecular Substances; D051178:alpha Catenin; D000185:Actinin; D016596:Vinculin; D002118:Calcium