ACTIN CYTOSKELETON SELF-ORGANIZATION IN EPITHELIAL CELLS

Abstract

I systematically investigated the principles of actin cytoskeleton self-organization in epithelial cells by confining isolated cells on isotropic adhesive islands, to be compared with fibroblasts. In fibroblasts, my lab previously described that an initially circular pattern of circumferential actin dynamically evolves into a radial pattern of actin bundles, which spontaneously breaks symmetry into a chiral pattern, before finally producing parallel linear stress fibres. Epithelial cells on the other hand, did not exhibit succession through all the actin patterns described above. The actin cytoskeleton in non-keratinocyte epithelial cells is arrested at the circular stage, while in keratinocytes it can progress as far as the radial pattern. Epithelial-mesenchymal transition pushed actin cytoskeleton development from circular towards radial patterns but remains insufficient to cause chirality. The role of cell-matrix and cell-cell adhesions in directing actin cytoskeleton development was also examined by comparing cells plated on cadherin and different matrix coated adhesive islands.