Intermediate filaments interact with dormant ezrin in intestinal epithelial cells

Flavia A. Wald, Andrea S. Oriolo, M. Llanos Casanova, Pedro J.I. Salas

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Ezrin connects the apical F-actin scaffold to membrane proteins in the apical brush border of intestinal epithelial cells. Yet, the mechanisms that recruit ezrin to the apical domain remain obscure. Using stable CACO-2 transfectants expressing keratin 8 (K8) antisense RNA under a tetracycline-responsive element, we showed that the actin-ezrin seaffold cannot assemble in the absence of intermediate filaments (IFs). Overexpression of ezrin partially rescued this phenotype. Overexpression of K8 in mice also disrupted the assembly of the brush border, but ezrin distributed away from the apical membrane in spots along supernumerary IFs. In cytochalasin D-treated cells ezrin localized to a subapical compartment and coimmunoprecipitated with IFs. Overexpression of ezrin in undifferentiated cells showed a Triton-insoluble ezrin compartment negative for phospho-T567 (dormant) ezrin visualized as spots along IFs. Pulse-chase analysis showed that Triton-insoluble, newly synthesized ezrin transiently coimmunopreeipitates with IFs during the first 30 min of the chase. Dormant, but not active (p-T567), ezrin bound in vitro to isolated denatured keratins in Far-Western analysis and to native IFs in pull-down assays. We conclude that a transient association to IFs is an early step in the polarized assembly of apical ezrin in intestinal epithelial cells.

Original languageEnglish (US)
Pages (from-to)4096-4107
Number of pages12
JournalMolecular biology of the cell
Issue number9
StatePublished - Sep 2005

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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