Periplakin-dependent re-organisation of keratin cytoskeleton and loss of collective migration in keratin-8-downregulated epithelial sheets

HA Long, V Boczonadi, L McInroy… - Journal of cell …, 2006 - journals.biologists.com
HA Long, V Boczonadi, L McInroy, M Goldberg, A Määttä
Journal of cell science, 2006journals.biologists.com
Collective migration of epithelial sheets requires maintenance of cell-cell junctions and co-
ordination of the movement of the migrating front. We have investigated the role of keratin
intermediate filaments and periplakin, a cytoskeletal linker protein, in the migration of simple
epithelial cells. Scratch wounding induces bundling of keratins into a cable of tightly packed
filaments adjacent to the free wound edge. Keratin re-organisation is preceded by a re-
distribution of periplakin away from the free wound edge. Periplakin participates with …
Collective migration of epithelial sheets requires maintenance of cell-cell junctions and co-ordination of the movement of the migrating front. We have investigated the role of keratin intermediate filaments and periplakin, a cytoskeletal linker protein, in the migration of simple epithelial cells. Scratch wounding induces bundling of keratins into a cable of tightly packed filaments adjacent to the free wound edge. Keratin re-organisation is preceded by a re-distribution of periplakin away from the free wound edge. Periplakin participates with dynamic changes in the keratin cytoskeleton via its C-terminal linker domain that co-localises with okadaic-acid-treated keratin granules. Stable expression of the periplakin C-terminal domain increases keratin bundling and Ser431 keratin phosphorylation at wound edge resulting in a delay in wound closure. Ablation of periplakin by siRNA inhibits keratin cable formation and impairs wound closure. Knockdown of keratin 8 with siRNA results in (1) a loss of desmoplakin localisation at cell borders, (2) a failure of MCF-7 epithelial sheets to migrate as a collective unit and (3) accelerated wound closure in vimentin-positive HeLa and Panc-1 cell lines. Thus, keratin 8 is required for the maintenance of epithelial integrity during migration and periplakin participates in the re-organisation of keratins in migrating cells.
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