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Title: Functional characterisation of ECOP, a novel regulator of the NFκB signalling pathway
Author: Saivaree, Niramon
ISNI:       0000 0004 7428 8019
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2014
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EGFR-coamplified and overexpressed protein (ECOP), also known as VOPP1/GASP, is overexpressed in several cancers including glioblastoma and squamous cell carcinoma (SCC). ECOP up-regulates the prosurvival effects ofNFKB signalling. Previous studies have demonstrated that ECOP confers that its effect on NFKB in a cell-type specific manner. ECOP activates NFKB signalling in HEK293T and HeLa cells, but does not have an effect on NFKB in human SCC. However, biological characterisation ofECOP function on NFKB signalling has yet to be elucidated. This study analysed the interactions ofECOP with members of the Nedd4-family ofE3 Iigases using co-IP in HEK293T cells and demonstrated that the PY motifs within ECOP were involved in these interactions. Furthermore, subcellular localisation ofNEDLl was affected by mutations of the PY motifs ofECOP. Using luciferase reporter assays, it was shown that ECOP up› regulated NFKB activity supporting the published data. NEDLI alone did not affect TNFa› induced NFKB signalling whereas co-expression with ECOP resulted in an elevation ofNFKB signalling suggesting that ECOP may have a role in the activation ofNEDLl ubiquitination activity involved in the NFKB pathway. A stable interaction ofECOP with NEDLI in the absence ofTNFa indicates that ECOP and NEDLI reside in close proximity and ECOP may trigger the activity ofNEDLl with TNFa stimulation. Mediators of the NFKB pathway interacted with ECOP in a co-IP study. Additionally, ECOP was co-localised with markers of endosomes, suggesting that ECOP may be involved in membrane trafficking. Post-translational modification by ubiquitination of ECOP was also demonstrated although the reason for this modification remains unclear. The relationship between the family ofNedd4-like E3 Iigases and the NFKB pathway by a direct involvement ofECOP has been revealed for the first time in this thesis. The results described in these studies supports a role for ECOP in NFKB signalling in HEK293T cells that confers prosurvival effects ofNFKB.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available