Influence of protein kinase C on transcription of the tight junction elements ZO-1 and occludin.
Tight junctions as an epithelial barrier against paracellular diffusion have mainly been investigated on the protein level with particular respect to subcellular localization. In this study, real-time PCR has been established to investigate the influence of protein kinase C (PKC) modulation on the transcription of tight junction elements occludin and ZO-1 in the cell line T84. Activation of PKC by the phorbol ester TPA induced ZO-1 and occludin transcription, whereas PKC inhibition lead to decreased expression levels. Activation of PKC exerted its effect on transcript level directly. PKC signal was partially transduced via MEK1/MEK2 but depended strongly on MAPK independent pathways probably involving nuclear localized PKC, whereas p38 signaling was not implicated. TPA induced loss of function concomitant with a dislocation of ZO-1 and occludin could be prevented by inhibition of MEK1 by PD98059. Overall ZO-1 and occludin seem to be identically regulated in colonic epithelium on the transcript level.
Weiler
Frank
F
Department of Medicine, Division of Gastroenterology, University of Wuerzburg, Wuerzburg, Germany. weiler_f@klinik.uni-wuerzburg.de
Marbe
Theresa
T
Scheppach
Wolfgang
W
Schauber
Jürgen
J
D002273:Carcinogens / Q000494:pharmacology; D002460:Cell Line; D017097:Electric Impedance; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics*; D062793:Occludin; D010750:Phosphoproteins / Q000235:genetics*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019108:Tight Junctions / Q000201:enzymology*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D062826:Zonula Occludens-1 Protein
D002273:Carcinogens; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D013755:Tetradecanoylphorbol Acetate