Mammalian Fat1 cadherin regulates actin dynamics and cell-cell contact

Tanoue T and Takeichi M
Source: J Cell Biol
Publication Date: (2004)
Issue: 165(4): 517-528
Research Area:
Cancer Research/Cell Biology
Dermatology/Tissue Engineering
Cells used in publication:
Species: rat
Tissue Origin: kidney
Species: mouse
Tissue Origin: dermal
Nucleofectorâ„¢ I/II/2b
Transfection of the transformed mouse keratinocyte cell line PAM212 with an RNAi vector for Fat 1 reduced Fat1 protein by more than 95% and led to significant changes in the distribution and localization of proteins downstream of Fat 1, like beta-catenin and F-actin. Expression of Flag-tagged variants of Fat 1 in the rat renal epithelial cell line NRK-52E revealed Fat 1's influence on localization of its interaction partner VASP. As a further interaction test, in NRK-52E cells, a fusion of Fat 1 to a mitochondrial targeting sequence localized to mitochondria and also recruited VASP to this organelle.
Fat cadherins form a distinct subfamily of the cadherin gene superfamily, and are featured by their unusually large extracellular domain. In this work, we investigated the function of a mammalian Fat cadherin. Fat1 was localized at filopodial tips, lamellipodial edges, and cell-cell boundaries, overlapping with dynamic actin structures. RNA interference-mediated knockdown of Fat1 resulted in disorganization of cell junction-associated F-actin and other actin fibers/cables, disturbance of cell-cell contacts, and also inhibition of cell polarity formation at wound margins. Furthermore, we identified Ena/vasodilator-stimulated phosphoproteins as a potential downstream effector of Fat1. These results suggest that Fat1 regulates actin cytoskeletal organization at cell peripheries, thereby modulating cell contacts and polarity.