2004 IRISH SCIENTIST YEAR BOOK

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Dublin City University & Royal College of Surgeons of Ireland
Tia Keyes, Robert Forster, Dermot Kenny & Niamh Moran
Thrombosis – a sticky business!

Thrombosis involves the clotting of blood within an artery or a vein. This is always abnormal and is often dangerous, as it can reduce or stop the flow of blood. When thrombosis affects important arteries, such as the coronary arteries (causing a heart attack) or the arteries supplying the brain with blood (causing a stroke), it is a major cause of death and serious illness. During the past decade, considerable progress has been made at the RCSI to identify the role of the aIIbß3 complex in platelet-mediated thrombus formation, as this integrin has been identified as a pivotal mediator of platelet aggregation. Therefore, it is a logical target for therapeutic measures to control thrombus formation.

The holy grail has been to visualize single proteins within a natural or mimetic cell membrane while undergoing its normal function, e.g., undergoing a conformational change when challenged by an agonist.

In collaboration with Dermot Kenny and Niamh Moran of the RCSI, Tia Keyes and Robert Forster of DCU are developing this 'molecular scale movie' by simultaneously observing conformational and electrical changes as agonists bind, the protein conformation changes, and the clotting cascade is initiated. To achieve this goal, we are exploring novel nanostructured cavities that uniquely enable simultaneous optical and electrochemical measurements on single proteins under well-defined agonist conditions. The team is developing techniques, such as plasmonic enhanced fluorescence and surface enhanced raman spectroscopy, that can detect conformational change. For example, fluorescence resonance energy transfer (FRET) is being exploited to visualize protein conformation change in real time. FRET involves using two dyes: a donor fluorophore transfers energy in a strongly distant and orientation-dependent fashion to an acceptor fluorophore. Hence the distance, or possibly orientation, of the two dyes, can be measured, yielding information about protein conformational changes when an agonist or therapeutic agent, e.g., aspirin, is present. Understanding the specifics of conformational change in this sticky platelet protein is critical to the development of novel therapeutic agents for the treatment of thrombosis.


Changes in the fluorescence intensity and the fluorescence polarization of the integrin upon activation.

Contact: Dr Tia Keyes, School of Chemical Sciences, Dublin City University, Dublin 9;
Tel. 353-1-7008185; E-mail: [email protected]