Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biological Engineering, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 106-116). / Heparin-binding epidermal growth factor-like growth factor (HB-EGF) exhibits activity as a juxtacrine, paracrine, and autocrine ligand for the epidermal growth factor receptor (EGFR), and possesses the ability to bind heparan sulfate proteoglycans (HSPGs). The interaction of HB-EGF with HSPGs has been previously studied only with the soluble (autocrine/paracrine) form of the protein (sHB-EGF), produced after proteolytic cleavage of the transmembrane form (proHB-EGF) from the cell surface. It was hypothesized that HSPGs interact with proHB-EGF in ways that could alter behavior of the transmembrane form of this ligand and consequent processes. Using an engineered form of proHB-EGF that allowed for independent tracking of the extracellular domain and the C-terminal tail, proHB-EGF was observed primarily at sites of cell-cell contact. However, a dramatic change in this localization was observed upon the addition of exogenous heparin, heparan sulfate, heparinase III or mutation of the heparin-binding domain of proHB-EGF, suggesting that an interaction with HSPGs is responsible for localizing proHB-EGF to sites of cell-cell contact. Further studies in wild-type CHO-Ki cells and heparan sulfate deficient CHOpgsD-677 cells demonstrated that a trans interaction between proHB-EGF and HSPGs on neighboring cells was responsible for this localization. Additionally, this interaction inhibited proteolytic processing of the ligand, as heparin and mutation of the heparin-binding domain increased the amount of sHB-EGF accumulated in the media. / by Robin N. Prince. / Ph.D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/61233 |
| Date | January 2009 |
| Creators | Prince, Robin Neely |
| Contributors | Douglas A. Lauffenburger and Richard T. Lee., Massachusetts Institute of Technology. Dept. of Biological Engineering., Massachusetts Institute of Technology. Department of Biological Engineering |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 116 p., application/pdf |
| Rights | MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission., http://dspace.mit.edu/handle/1721.1/7582 |
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