Characterisation of novel functions of the anaphase promoting complex/cyclosome and its regulation through post-translational modification

Minshall, Paul Edward (2015). Characterisation of novel functions of the anaphase promoting complex/cyclosome and its regulation through post-translational modification. University of Birmingham. Ph.D.

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Abstract

The Anaphase Promoting Complex/Cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase that regulates mitotic progression through targeting substrates for degradation by the 26S proteasome. In order to assess APC/C post-translational modification status, and identify novel APC/C substrates and regulators, a comprehensive analysis of the APC/C and APC/C-interacting proteins by mass spectrometry was undertaken.

RNA polymerase I was identified as an APC/C-interacting complex, and the interaction was validated by reciprocal co-immunoprecipitation, GST pull-down and immunofluorescent confocal microscopy. Both RPA194 protein levels and RNA Polymerase I transcription were shown to be dependent upon APC/C activity. Ablation of APC/C function by RNAi interference increased RPA194 protein levels, and elevated RNA polymerase I activity significantly, as quantified by 5’-Fluorouridine incorporation into nascent pre-rRNA, and the increase in absolute levels of 45S, 28S and 18S rRNA transcripts, relative to non-silencing controls.

A number of other potential APC/C substrates and regulators were identified by mass spectrometry. Many of these interacting proteins contained APC/C consensus degron motifs. The APC/C was also shown to be a major substrate for acetylation; a number of APC/C subunits were identified as being acetylated in vivo. In this regard, APC3 was shown to be a substrate for both CBP and p300 acetyltransferases.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Supervisor(s):
Supervisor(s)EmailORCID
Turnell, AndrewUNSPECIFIEDUNSPECIFIED
Grand, RogerUNSPECIFIEDUNSPECIFIED
Licence:
College/Faculty: Colleges (2008 onwards) > College of Medical & Dental Sciences
School or Department: Institute of Cancer Studies
Funders: None/not applicable
Subjects: R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer)
URI: http://etheses.bham.ac.uk/id/eprint/5694

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