Back to Search
Start Over
Polarization of Specific Tropomyosin Isoforms in Gastrointestinal Epithelial Cells and Their Impact on CFTR at the Apical Surface
- Source :
- Molecular Biology of the Cell. 14:4365-4375
- Publication Year :
- 2003
- Publisher :
- American Society for Cell Biology (ASCB), 2003.
-
Abstract
- Microfilaments have been reported to be polarized in a number of cell types based both on function and isoform composition. There is evidence that microfilaments are involved in the movement of vesicles and the polarized delivery of proteins to specialized membrane domains. We have investigated the composition of actin microfilaments in gastrointestinal epithelial cells and their role in the delivery of the cystic fibrosis transmembrane conductance regulator (CFTR) into the apical membrane using cultured T84 cells as a model. We identified a specific population of microfilaments containing the tropomyosin (Tm) isoforms Tm5a and/or Tm5b, which are polarized in T84 cell monolayers. Polarization of this microfilament population occurs very rapidly in response to cell-cell and cell-substratum contact and is not inhibited by jasplakinolide, suggesting this involves the movement of intact filaments. Colocalization of Tm5a and/or Tm5b and CFTR was observed in long-term cultures. A reduction in Tm5a and Tm5b expression, induced using antisense oligonucleotides, resulted in an increase in both CFTR surface expression and chloride efflux in response to cAMP stimulation. We conclude that Tm isoforms Tm5a and/or Tm5b mark an apical population of microfilaments that can regulate the insertion and/or retention of CFTR into the plasma membrane.
- Subjects :
- Population
Cystic Fibrosis Transmembrane Conductance Regulator
Antineoplastic Agents
Tropomyosin
Microfilament
Peptides, Cyclic
Chlorides
Depsipeptides
Cell Adhesion
Cyclic AMP
Tumor Cells, Cultured
Humans
Protein Isoforms
education
Molecular Biology
Actin
education.field_of_study
biology
Epithelial Cells
Articles
Cell Biology
Oligonucleotides, Antisense
Apical membrane
Actin cytoskeleton
Actins
Cystic fibrosis transmembrane conductance regulator
Cell biology
Transport protein
Gastrointestinal Tract
Actin Cytoskeleton
Protein Transport
biology.protein
Subjects
Details
- ISSN :
- 19394586 and 10591524
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Molecular Biology of the Cell
- Accession number :
- edsair.doi.dedup.....1f65bcd8747e278954c25a99fe016780