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Effects of keratin phosphorylation on the mechanical properties of keratin filaments in living cells
Author(s) -
Fois Giorgio,
Weimer Michael,
Busch Tobias,
Felder Erika T.,
Oswald Franz,
Wichert Götz,
Seufferlein Thomas,
Dietl Paul,
Felder Edward
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.12-215632
Subject(s) - keratin , intermediate filament , keratin 8 , keratin 5 , keratin 6a , actin , phosphorylation , microbiology and biotechnology , chemistry , keratin 7 , cytoskeleton , myosin , biology , cell , biochemistry , immunology , genetics , cytokeratin , immunohistochemistry
Keratin filaments impart resilience against mechanical extension of the cell. Despite the pathophysiological relevance of this function, very little is known about the mechanical properties of intermediate filaments in living cells and how these properties are modulated. We used keratin mutants that mimic or abrogate phosphorylation of keratin 8‐serine 431 and keratin 18‐serine 52 and investigated their effect on keratin tortuousness after cell stretch release in squamous cell carcinoma cells. Cells transfected with the wild‐type keratins were used as controls. We can show that keratin dephosphorylation alters the stretch response of keratin in living cells since keratin tortuousness was abolished when phosphorylation of keratin18‐serine 52 was abrogated. Additional experiments demonstrate that keratin tortuousness is not simply caused by a plastic overextension of keratin filaments because tortuousness is reversible and requires an intact actin‐myosin system. The role of actin in this process remains unclear, but we suggest anchorage of keratin filaments to actin during stretch that leads to buckling on stretch release. Dephosphorylated keratin18‐serine 52 might strengthen the recoil force of keratin filaments and hence explain the abolished buckling. The almost exclusive immunolabeling for phosphorylated keratin18‐serine 52 in the cell periphery points at a particular role of the peripheral keratin network in this regard.—Fois, G., Weimer, M., Busch, T., Felder, E. T., Oswald, F., von Wichert, G., Seufferlein, T., Dietl, P., Felder, E. Effects of keratin phosphorylation on the mechanical properties of keratin filaments in living cells. FASEB J. 27, 1322–1329 (2013). www.fasebj.org