Comparative study of ezrin phosphorylation among different tissues: more is good; too much is bad.

  • Zhu L
  • Hatakeyama J
  • Chen C
 et al. 
  • 18

    Readers

    Mendeley users who have this article in their library.
  • 15

    Citations

    Citations of this article.

Abstract

In a comparison of three different tissues, the membrane cytoskeleton linker protein ezrin was found to assume high levels of phosphorylation on threonine-567 (T567) in the brush border membranes of renal proximal tubule cells and small intestine enterocytes, in contrast to the apical canalicular membrane of gastric parietal cells. Together with an earlier observation that increased T567 phosphorylation is associated with more elaborate microvilli in parietal cells, this comparative study suggested a higher phosphorylation level requirement for the denser and more uniform distribution of microvilli at brush border surfaces. Using a kinase inhibitor, staurosporin, and metabolic inhibitor, sodium azide, relatively high turnover of ezrin T567 phosphorylation was observed in all three epithelia. Aiming to understand the role of phosphorylation turnover in these tissues, detergent extraction analysis of gastric glands and proximal tubules revealed that an increased phosphorylation on ezrin T567 greatly enhanced its association with F-actin, while ezrin-membrane interaction persisted regardless of the changes of phosphorylation level on ezrin T567. Finally, expression of Thr567Asp mutant ezrin, which mimics the phospho-ezrin state but does not allow turnover, caused aberrant growth of membrane projections in cultured proximal tubule cells, consistent with what had previously been observed in several cell lines and gastric parietal cells. These results fit into a model of surface plasticity, which posits that the turnover of phosphorylation on T567 empowers ezrin to relax and reposition membrane to the underlying cytoskeleton under varying conditions of filament growth or rapid membrane expansion (or depletion).

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Lixin Zhu

  • Jason Hatakeyama

  • Cheng Chen

  • Aditi Shastri

  • Kevin Poon

  • John G Forte

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free