Investigation of p75 neurotrophin receptor and the role of its post-translational modifications in tumour cell motility and invasiveness

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dc.contributor.advisor McCarthy, Justin V. en Berghoff, Janina 2014-05-12T14:29:36Z 2013 2013
dc.identifier.citation Berghoff, J. 2013. Investigation of p75 neurotrophin receptor and the role of its post-translational modifications in tumour cell motility and invasiveness. PhD Thesis, University College Cork. en
dc.identifier.endpage 288
dc.description.abstract The p75 neurotrophin receptor (p75NTR) is a member of the tumour necrosis factor superfamily, which relies on the recruitment of cytosolic protein partners - including the TNF receptor associated factor 6 (TRAF6) E3 ubiquitin ligase - to produce cellular responses such as apoptosis, survival, and inhibition of neurite outgrowth. Recently,p75NTR was also shown to undergo γ-secretase-mediated regulated intramembrane proteolysis, and the receptor ICD was found to migrate to the nucleus where it regulates gene transcription. Moreover, γ-secretase-mediated proteolysis was shown to be involved in glioblastoma cell migration and invasion. In this study we report that TRAF6-mediated K63-linked polyubiquitination at multiple or alternative lysine residues influences p75NTR-ICD stability in vitro. In addition, we found that TRAF6-mediated ubiquitination of p75NTR is not influenced by inhibition of dynamin. Moreover, we report beta-transducin repeats-containing protein (β-TrCP) as a novel E3- ligase that ubiquitinates p75NTR, which is independent of serine phosphorylation of the p75NTR destruction motif. In contrast to its influence on other substrates, co-expression of β-TrCP did not reduce p75NTR stability. We created U87-MG glioblastoma cell lines stably expressing wild type, γ-secretaseresistant and constitutively cleaved receptor, as well as the ICD-stabilized mutant K301R. Interestingly, only wild-type p75NTR induces increased glioblastoma cell migration, which could be reversed by application of γ-secretase inhibitor. Microarray and qRT-PCR analysis of mRNA transcripts in these cell lines yielded several promising genes that might be involved in glioblastoma cell migration and invasion, such as cadherin 11 and matrix metalloproteinase 12. Analysis of potential transcription factor binding sites revealed that transcription of these genes might be regulated by well known p75NTR signalling cascades such as NF-κB or JNK signalling, which are independent of γ-secretase-mediated cleavage of the receptor. In contrast, while p75NTR overexpression was confirmed in melanoma cell lines and a patient sample of melanoma metastasis to the brain, inhibition of γ-secretase did not influence melanoma cell migration. Collectively, this study provides several avenues to better understand the physiological importance of posttranslational modifications of p75NTR and the significance of the receptor in glioblastoma cell migration and invasion. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2013, Janina Berghoff. en
dc.rights.uri en
dc.subject Cancer Biology en
dc.subject p75 neurotrophin receptor en
dc.subject Ubiquitination en
dc.subject Glioblastoma en
dc.subject Gamma-secretase-mediated proteolysis en
dc.subject Microarray en
dc.subject Cancer cell migration en
dc.title Investigation of p75 neurotrophin receptor and the role of its post-translational modifications in tumour cell motility and invasiveness en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral Degree (Structured) en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en Indefinite en 10000-01-01
dc.description.version Accepted Version
dc.contributor.funder Health Research Board en
dc.description.status Not peer reviewed en Biochemistry en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out No en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en

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© 2013, Janina Berghoff. Except where otherwise noted, this item's license is described as © 2013, Janina Berghoff.
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