Investigation of the interactions of retinoblastoma binding protein-6 with transcription factors p53 and Y-Box Binding Protein-1
Year: 2011
Type: dissertation
Abstract: Retinoblastoma Binding Protein 6 (RBBP6) is a 250 kDa multi-domain protein that a region corresponding to residues 1422-1668 of RBBP6.However in Nuclear Magnetic Resonance (NMR) chemical shift perturbation assays no evidence was found for the interaction.NMR showed the relevant region of RBBP6 to be unfolded, and no evidence was found for interaction-induced folding.The R273H mutant of the p53 core domain did not abolish the interaction, in contrast to reports that the corresponding murine mutation (R270C) did abolish the interaction.The second part of this thesis describes in vitro investigations of the ubiquitination of YB-1 by RBBP6.A fragment corresponding to the first 335 residues of RBBP6, denoted R3, was expressed in bacteria and found to be soluble.Contrary to expectation, in a fully in vitro assay R3 was not able to ubiquitinate YB-1.However, following addition of human cell lysate, YB-1 was degraded in an R3-dependent and proteasome-dependent manner, indicating that R3 is required for ubiquitination and proteasomal degradation of YB-1.However R3 is not sufficient, with one or more factors being supplied by the cell lysate.In view of the pro-tumourigenic effects of YB-1 in many human cancers, these results lay the foundation for an understanding of the regulatory effect of RBBP6 on YB-1 and its potential role in anti-tumour therapy.
Author: Andrew Faro
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2745676799