Distinct effects of protein kinase C on the barrier function at different developmental stages.
We show here, that activation of protein kinase C by the phorbol ester PMA improves barrier function in colon carcinoma (HT 29) cells. By contrast, in canine kidney (MDCK I) cells it caused increased permeability and opening of tight junctions; the latter has also been noticed in other studies. Thus, with PMA confluent HT 29 cells responded with a reduced passage of 330 kDa sodium fluorescein, increased transepithelial electrical resistance, and a change in the cell shape of the HT 29 cells from an irregular to a regular, hexagonal form. Confocal imaging revealed parallel distinct changes in the staining of occludin and caludin-1, viz. a translocation from cytoplasmic clusters to apical cell-cell contacts. Interestingly, in both cell lines protein kinase A activation caused a decreased in the threonine phosphorylation of occludin that correlated with tight junction assembly in HT 29 cells and tight junction disassembly in MDCK I cells. We conclude that protein kinase C regulation of the epithelial barrier involves specific molecular mechanisms and achieves distinct effects at different developmental stages.
Division of Medical Microbiology, Department of Molecular and Clinical Medicine, Linköping University, SE-581 85 Linköping, Sweden. anisj@imk.liu.se
Anita
A
Sjö
Karl-Eric
KE
Magnusson
Kajsa Holmgren
KH
Peterson
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002463:Cell Membrane Permeability / Q000187:drug effects; D062445:Claudin-1; D017097:Electric Impedance; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D019793:Fluorescein / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology; D019073:HT29 Cells; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008857:Microscopy, Interference; D062793:Occludin; D010703:Phorbol Esters / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010769:Phosphothreonine / Q000378:metabolism; D011233:Precipitin Tests; D011493:Protein Kinase C / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D019108:Tight Junctions / Q000502:physiology*; D013997:Time Factors
C568108:CLDN1 protein, human; D062445:Claudin-1; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010703:Phorbol Esters; D010769:Phosphothreonine; C119222:phorbol-12-myristate; D011493:Protein Kinase C; D019793:Fluorescein