Characterisation of an ubiquitin binding CUE domain in presenilin-1

Duggan, Stephen

Characterisation of an ubiquitin binding CUE domain in presenilin-1

dc.check.opt-out	Yes	en
dc.check.reason	This thesis is due for publication or the author is actively seeking to publish this material	en
dc.contributor.advisor	McCarthy, Justin V.	en
dc.contributor.author	Duggan, Stephen
dc.contributor.funder	Irish Research Council for Science Engineering and Technology	en
dc.date.accessioned	2016-05-23T11:31:47Z
dc.date.issued	2016
dc.date.submitted	2016
dc.description.abstract	The presenilins are the catalytic component of the gamma-secretase protease complex, involved in the regulated intramembrane proteolysis of numerous type-1 transmembrane proteins, including Amyloid precursor protein (APP) and Notch. In addition to their role in the γ-secretase complex the presenilins are involved in a number of γ-secretase independent functions such as calcium homeostasis, apoptosis, inflammation and protein trafficking. Presenilin function is known to be regulated through posttranslational modifications like endoproteolysis, phosphorylation and ubiquitination. Using a bioinformatics and protein sequence analysis approach this lab has identified a putative ubiquitin binding CUE domain in the presenilins. The aim of this project was to characterise the function of the presenilin CUE domains. Firstly, the presenilins are shown to contain a functional ubiquitin-binding CUE domain that preferentially binds to K63-linked polyubiquitin chains. The PS1 CUE domain is shown to be dispensable for PS1 endoproteolysis and γ-secretase mediated cleavage of APP, Notch and IL-1R1. This suggests the PS1 CUE domain is involved in a γ-secretase independent PS1 function. Our hypothesis is that the PS1 CUE domain is involved in regulating PS1’s intermolecular protein-protein interactions or intramolecular PS1:PS1 interactions. Here the PS1 CUE domain is shown to be dispensable for the interaction of PS1 and the K63-linked polyubiquitinated PS1 interacting proteins P75NTR, IL-1R1, TRAF6, TRAF2 and RIP1. To further investigate PS1 CUE domain function a mass spectrometry proteomics based approach is used to identify PS1 CUE domain interacting proteins. This proteomics approach demonstrated that the PS1 CUE domain is not required for PS1 dimerization. Instead a number of proteins thatinteract with the PS1 CUE domain are identified as well as proteins whose interaction with PS1 is downregulated by the presence of the PS1 CUE domain. Bioinformatic analysis of these proteins suggests possible roles for the PS1 CUE domain in regulating cell signalling, ubiquitination or cellular trafficking.	en
dc.description.sponsorship	Irish Research Council for Science Engineering and Technology (IRCSET Grant RS/2012/407)	en
dc.description.status	Not peer reviewed	en
dc.description.version	Accepted Version
dc.format.mimetype	application/pdf	en
dc.identifier.citation	Duggan, S.P. 2016. Characterisation of an ubiquitin binding CUE domain in presenilin-1. PhD Thesis, University College Cork.	en
dc.identifier.endpage	236	en
dc.identifier.uri	https://hdl.handle.net/10468/2599
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.rights	© 2016, Stephen P. Duggan.	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/	en
dc.subject	Presenilins	en
dc.subject	Ubiquitin	en
dc.subject	Ubiquitin binding domains	en
dc.thesis.opt-out	true
dc.title	Characterisation of an ubiquitin binding CUE domain in presenilin-1	en
dc.type	Doctoral thesis	en
dc.type.qualificationlevel	Doctoral	en
dc.type.qualificationname	PhD (Science)	en