Nick Holliday
RCUK Academic Fellow in Functional Imaging, Faculty of Medicine & Health Sciences
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Expertise Summary
I am interested in the signalling and regulation of peptide and nutrient G protein coupled receptors (GPCRs). These GPCRs, for peptides such as neuropeptide Y and ghrelin, and nutrients such as free fatty acids, are implicated in the control of appetite and body weight. As such they provide new drug targets to treat diabetes and obesity. We therefore need an understanding of the cellular mechanisms that alter receptor function in the long-term treatment of these conditions
In particular my lab focuses on understanding the mechanisms that drive intracellular GPCR trafficking. This is the movement of receptor proteins from the plasma membrane to intracellular compartments that control their recycling or degradation. In turn this determines the life-span of GPCR proteins under conditions of long-term stimulation. We use a variety of methods to approach the problem, including site directed mutagenesis of the receptors and partner proteins, and immunofluorescence microscopy to study the location of the receptors and their colocalisation with other cellular components - including automated high content imaging and quantitative analysis.
Recently we have applied biomecular fluorescence complementation (BiFC) to study the interactions between GPCRs and an important regulator protein called arrestin. In BiFC we add two halves of a fluorescent protein to the receptor and arrestin molecules, so that the light from it will only be seen when the segments are brought together by a receptor-arrestin complex. This provides a quantitative measure of receptor-arrestin interactions, and also allows us to study the complexes formed by powerful fluorescence imaging methods. This will tell us more about the molecular controls that govern the formation of different receptor-arrestin combinations, and how these controls generate alternative patterns of signalling. We are currently expanding the use of BiFC to study spatial organisation of GPCR signalling in the cell membrane, endosomes and the nucleus.
Research Interests
Mechanisms of GPCR internalisation and intracellular trafficking.
The influence of spatial organisation on GPCR signalling.
Neuropeptide Y and free fatty acid receptors in cell proliferation and apoptosis.
Research Expertise
Peptide GPCR pharmacology (binding and signalling assays)
Detection of post-translation protein modifications (palmitoylation, phosphorylation)
High content confocal imaging and analysis
Bimolecular fluorescence complementation to detect protein interactions
Selected Publications
JORGENSEN, R, HOLLIDAY, ND, HANSEN, JL, VRECL, M, HEDING, A, SCHWARTZ, TW and ELLING, CE, 2008. Characterization Of G-Protein Coupled Receptor Kinase Interaction With The Neurokinin-1 Receptor Using Bioluminescence Resonance Energy Transfer Molecular Pharmacology. 73(2), 349-358