The Role of Gap Junctions in Cellular Migration
Bado Hewa DeFranco, MS.
University of Pittsburgh, 2009
The body of work presented here focuses on characterizing the role that gap junction intercellular channels play in regulating cellular migration. Cell migration is a ubiquitous process that is required for embryonic development and for maintaining the integrity of tissues and organs. Yet, the status of gap junction channels, with regard to structure and function, in migrating cells is not completely understood. We hypothesized that, Gap junction channels, as mediators of intercellular communication, play a role in cell migration, and have investigated and characterized gap junctions in migrating cells. Accordingly, the aims of this dissertation were: (i) to characterize gap junctions and their function during migration, (ii) to determine the effect of altering the status of gap junction expression on cell migration and to (iii) characterize the mechanism of gap junction internalization in migrating cells.
With combined molecular and imaging approaches we have demonstrated that in cells migrating as a sheet, gap junction plaque structures are retained on the plasma membrane surface; that gap junction communication is continuous in migrating cells and that interrupting this communication with connexin 43 specific mimetic peptides reduces migration. We have established a system in a human adrenal cortical cell line (SW13) wherein we significantly reduce gap junction protein expression with siRNA and show that cellular migration is inhibited. We have also demonstrated that gap junction plaque size and orientation are modified during migration. We also discovered that sometimes, migrating cells will spontaneously detach from one another at cellular processes and that during this event the gap junction plaques are internalized. Analysis of gap junction plaque internalization in migrating cells revealed that clathrin and several adaptor proteins associate with surface gap junctions and cytoplasmic annular gap junction structures and possibly regulate the unique mechanism of gap junction plaque removal from the plasma membrane. Within the field of gap junction research this work expands our understanding of gap junctions in living cells as dynamic structures that may play a key role in coordinating the migration of entire cell populations.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-10122009-153156 |
| Date | 27 October 2009 |
| Creators | DeFranco, Bado Hewa |
| Contributors | Sandra Murray, Allan Zhao, David Hackam, Nirmala SundarRaj, Carl Lagenaur, Peter Drain |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-10122009-153156/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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