Project: Research project

Project Details


The hypotheses of this project are: a) The ATP depletion in epithelial
cells results in the depolymerization of actin microfilaments that form the
microvillar core, and, thus, in either the release/depolarization of apical
cytoskeletally anchored plasma membrane proteins, the loss of vectorial
delivery of membrane proteins, or both. b) The intermediate filaments of
the terminal web carry organizers to reassemble the rootlets of the
microvillar cores during the recovery after an ischemia-like injury. To
test these hypotheses, I propose the following specific aims;

1- Determine the extent, morphology and kinetics of actin depolymerization
and repolymerization due to ischemia/ recovery situations in epithelial
cells. The actin depolymerization/repolymerization will be analyzed in
epithelial cells in tissue culture depleted in ATP by biochemical methods,
immunofluorescence and immunoelectronmicroscopy.

2- Determine the role of terminal web and an apical 53 kD cytokeratin as
potential organizers of actin repolymerization after an ischemia-like
injury. Specific antibodies against an apically localized 53 kD
cytokeratin and fimbrin introduced in the cytoplasm will be used to block
of microvillar reassembly. Anti-sense oligonucleotides will be used to
hinder the synthesis of the 53 kD protein. Organization of microfilaments
on IF will be studied after ATP depletion.

3- Analyze the relationship between actin depolymerization following an
ischemia-like injury and loss in epithelial plasma membrane polarity.
Polarization of apical and basolateral plasma membrane markers will be
analyzed as a function of cytoskeletal disruption after ischemia.
Effective start/end date4/1/953/31/01


  • National Heart, Lung, and Blood Institute
  • National Heart, Lung, and Blood Institute
  • National Heart, Lung, and Blood Institute
  • National Heart, Lung, and Blood Institute
  • National Heart, Lung, and Blood Institute


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