Protein kinase C regulates the phosphorylation and cellular localization of occludin

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Item Type:	Article
Title:	Protein kinase C regulates the phosphorylation and cellular localization of occludin
Creators Name:	Andreeva, A.Y., Krause, E., Mueller, E.C., Blasig, I.E. and Utepbergenov, D.I.
Abstract:	Occludin is an integral membrane phosphoprotein specifically associated with tight junctions, contributing to the structure and function of this intercellular seal. Occludin function is thought to be regulated by phosphorylation, but no information is available on the molecular pathways involved. In the present study, the involvement of the protein kinase C pathway in the regulation of the phosphorylation and cellular distribution of occludin has been investigated. Phorbol 12-myristate 13-acetate and 1,2-dioctanoylglycerol induced the rapid phosphorylation of occludin in Madin-Darby canine kidney cells cultured in low extracellular calcium medium with a concomitant translocation of occludin to the regions of cell-cell contact. The extent of occludin phosphorylation as well as its incorporation into tight junctions induced by protein kinase C activators or calcium switch were markedly decreased by the protein kinase C inhibitor GF-109203X. In addition, in vitro experiments showed that the recombinant COOH-terminal domain of murine occludin could be phosphorylated by purified protein kinase C. Ser(338) of occludin was identified as an in vitro protein kinase C phosphorylation site using peptide mass fingerprint analysis and electrospray ionization tandem mass spectroscopy. These findings indicate that protein kinase C is involved in the regulation of occludin function at tight junctions.
Keywords:	Alkaline Phosphatase, Binding Sites, Calcium, Carcinogens, Cell Line, Cultured Cells, Cytoplasm, Detergents, Diglycerides, Dogs, Drug Dose-Response Relationship, Enzyme Activation, Enzyme Inhibitors, Fluorescence Microscopy, Indoles, Maleimides, Mass Electrospray Ionization Spectrometry, Mass Matrix-Assisted Laser Desorption-Ionization Spectrometry, Membrane Proteins, Occludin, Octoxynol, Phosphorylation, Precipitin Tests, Protein Kinase C, Recombinant Proteins, Serine, Tertiary Protein Structure, Tetradecanoylphorbol Acetate, Tight Junctions, Time Factors, Animals, Mice
Source:	Journal of Biological Chemistry
ISSN:	0021-9258
Publisher:	American Society for Biochemistry and Molecular Biology
Volume:	276
Number:	42
Page Range:	38480-38486
Date:	19 October 2001
Official Publication:	https://doi.org/10.1074/jbc.M104923200
PubMed:	View item in PubMed

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