An investigation into the localisation and possible protein partners of the base excision repair protein OGG1 and The role of Src-like adaptor proteins in regulating GPVI signalling

Akbar, Sarah (2013). An investigation into the localisation and possible protein partners of the base excision repair protein OGG1 and The role of Src-like adaptor proteins in regulating GPVI signalling. University of Birmingham. M.Res.

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Abstract

A common theme among the two research projects is the dichotomy of biological molecules or pathways contributing to both physiological and pathophysiological processes in vivo. Reactive oxygen species (ROS) are involved in redox signalling and phagocytosis, however when present in excess ROS attack cellular structures contributing to the progression of a number of degenerative pathologies such as Alzheimer’s and cardiovascular disease. Project 1 investigates the DNA repair protein OGG1 which counteracts the reactive species damage by repairing oxidised DNA base lesions. The DNA glycosylase OGG1 acts via the base excision repair (BER) pathway to mediate the nucleophilic excision of oxidised guanine residues 7,8-dihydro-8-oxoguanine (8-oxoG). The localisation of OGG1 is investigated in the cellular contexts of oxidative stress, apoptosis and mitosis. The protein partners of OGG1 were identified and compared to that of the single-nucleotide polymorphism variant Ser326Cys-OGG1to determine whether reduced repair capacity of the variant is due to impaired protein interactions.

Platelets mediate the physiological process of haemostasis and the pathophysiological process of thrombosis. GPVI is a glycoprotein platelet receptor integral to stable collagen binding at sites of vascular damage to activate haemostasis. As GPVI shares considerable homology to ITAM-receptors, it was hypothesised that GPVI is regulated by Src-like adaptor proteins (SLAP) which are the key negative regulators of ITAM-containing receptors of B cells and T cells. Project 2 investigates the regulation of GPVI by SLAP1 and SLAP2 in a DT40 cell line model using the NFAT/AP1-luciferase assay. Furthermore the contribution of each SLAP2 domain was investigated to elucidate a potential mechanism of SLAP2 mediated inhibition. SLAP1 and SLAP2 significantly inhibit collagen-stimulated GPVI signalling without altering GPVI expression levels indicating intrinsic inhibition of GPVI signalling. As SLAP proteins are expressed in platelets these are potential regulators of GPVI signalling in vivo. Elucidation of GPVI regulation could have implications in the development of anti-thrombosis therapy.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

Supervisor(s):