title: Ezrin is a Major Regulator of Membrane Tension in Epithelial Cells.
abstract: Plasma membrane tension is responsible for a variety of cellular functions such as motility, cell division, and endocytosis. Since membrane tension is dominated by the attachment of the actin cortex to the inner leaflet of the plasma membrane, we investigated the importance of ezrin, a major cross-linker of the membrane-cytoskeleton interface, for cellular mechanics of confluent MDCK II cells. For this purpose, we carried out ezrin depletion experiments and also enhanced the number of active ezrin molecules at the interface. Mechanical properties were assessed by force indentation experiments followed by membrane tether extraction. PIP2 micelles were injected into individual living cells to reinforce the linkage between plasma membrane and actin-cortex, while weakening of this connection was reached by ezrin siRNA and administration of the inhibitors neomycin and NSC 668394, respectively. We observed substantial stiffening of cells and an increase in membrane tension after addition of PIP2 micelles. In contrast, reduction of active ezrin led to a decrease of membrane tension accompanied by loss of excess surface area, increase in cortical tension, remodelling of actin cytoskeleton, and reduction of cell height. The data confirm the importance of the ezrin-mediated connection between plasma membrane and cortex for cellular mechanics and cell morphology.
authors.affiliation: Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen.
authors.forename: Bastian
authors.initials: B
authors.lastname: Rouven Brückner
authors.affiliation: Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen.
authors.forename: Anna
authors.initials: A
authors.lastname: Pietuch
authors.affiliation: Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen.
authors.forename: Stefan
authors.initials: S
authors.lastname: Nehls
authors.affiliation: Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen.
authors.forename: Jan
authors.initials: J
authors.lastname: Rother
authors.affiliation: Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, 37077 Goettingen.
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000502:physiology* / Q000648:ultrastructure; D048430:Cell Shape; D003598:Cytoskeletal Proteins / Q000502:physiology*; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D061985:Madin Darby Canine Kidney Cells; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D000099149:Ezrin
chemical_list: D000205:Actomyosin; D003598:Cytoskeletal Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D000099149:Ezrin