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Protein Kinase C-δ and Protein Kinase C-ε Cooperatively Enhance Epithelial Cell Spreading via Transactivation of Epidermal Growth Factor Receptor and Actin-Dependent Phosphorylation of Focal Adhesion-Associated Proteins

Song, Jaekyung Cecilia
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1132198567

Abstract Details

2005, PhD, University of Cincinnati, Medicine : Molecular and Cellular Physiology.
Regulation of epithelial cell motility requires coordinated actin rearrangement, yet the signaling pathways that lead to such modulation are not fully described. Previously we showed that protein kinase C (PKC) regulates actin remodeling in T84 intestinal epithelial cells but little is known regarding the role of PKC during cellular spreading. In subconfluent T84 cells, phorbol 12-myristate 13-acetate (PMA), which activates the conventional cPKC isoform PKCα and the novel nPKC isoforms PKCδ and PKCε of T84 cells, dramatically accelerated cell spreading with concurrent increase in tyrosine phosphorylation of the focal adhesion-associated proteins, Src, FAK and paxillin. These effects were abolished by the PKC inhibitor Gö6850 and PKCδ-specific inhibitor rottlerin. In contrast, the cPKC-selective inhibitor Gö6976 had no effect. Furthermore, siRNA-mediated down-regulation of PKCδ and PKCε, but not PKCα, attenuated cell spreading, implicating PKCδ and PKCε as the critical elements participating in regulation of epithelial cell spreading. Phosphorylation of FAK and paxillin by PMA was mediated by ligand-dependent transactivation of epidermal growth factor receptor (EGFr). Inhibition of EGFr signaling abolished PMA-induced phosphorylation of FAK and paxillin as well as cell spreading, indicating that EGFr transactivation plays a central role in mediating PMA-elicited cellular spreading. PMA caused PKCδ to translocate to the basal compartment, yet pretreatment with Gö6850 or siRNA against PKCε redistributed PKCδ to the lateral membrane; Gö6976, rottlerin, or siRNAs against PKCα or PKCδ were ineffective in preventing basal translocation of PKCδ. Inhibition of actin remodeling also redirected PKCδ to the lateral membrane, preventing PMA-induced phosphorylation of Src, FAK, and paxillin. These data demonstrate that actin remodeling by PKCε is critical for basal translocation of PKCδ and subsequent phosphorylation of focal adhesion targets, emphasizing the cooperation between two PKC isoforms for regulation of epithelial cell spreading. In response to scraped wounding, activation of PKCα, PKCδ and PKCε was evident. Pretreatment with Gö6850, but not Gö6976 or rottlerin, abolished lamellipodia formation and prevented cell migration toward the wound area. Increased phosphorylation of FAK and paxillin was also evident during wound healing. Taken together, the current study establishes a dynamic interplay between PKCδ and PKCε in regulation of epithelial cell motility.
Dr. Jeffrey Matthews (Advisor)
155 p.
Biology, Cell
Protein Kinase C; Cell spreading; Cell migration; Epithelial Cells; Epidermal Growth Factor Receptor; Transactivation; Focal Adhesion; Actin; Focal Adhesion Kinase; Src; Paxillin

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Citations

  • Song, J. C. (2005). Protein Kinase C-δ and Protein Kinase C-ε Cooperatively Enhance Epithelial Cell Spreading via Transactivation of Epidermal Growth Factor Receptor and Actin-Dependent Phosphorylation of Focal Adhesion-Associated Proteins [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1132198567

    APA Style (7th edition)

  • Song, Jaekyung Cecilia. Protein Kinase C-δ and Protein Kinase C-ε Cooperatively Enhance Epithelial Cell Spreading via Transactivation of Epidermal Growth Factor Receptor and Actin-Dependent Phosphorylation of Focal Adhesion-Associated Proteins. 2005. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1132198567.

    MLA Style (8th edition)

  • Song, Jaekyung Cecilia. "Protein Kinase C-δ and Protein Kinase C-ε Cooperatively Enhance Epithelial Cell Spreading via Transactivation of Epidermal Growth Factor Receptor and Actin-Dependent Phosphorylation of Focal Adhesion-Associated Proteins." Doctoral dissertation, University of Cincinnati, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1132198567

    Chicago Manual of Style (17th edition)

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© 2005, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.