School of Biosciences

Using fruit fly eyes as ion channel expression factories

PhD Research

Funding:

The full studentship (fees and stipend) is available to UK or EU students who have been resident in the UK for at least three years. Other EU participants may receive a fees only award.

Applicants capable of self-funding (UK, EU and international) are also welcome to apply.

Project Description:

P2X receptors are ATP-gated cation channels which play key roles in pain and inflammation, and they are major targets for analgesic and anti-inflammatory drugs. Progress in drug discovery is currently limited to traditional high-throughput screening, but if 3D crystal structures of mammalian P2X receptors in their ligand-bound states were available, rational structure-based drug design would be possible.

Recently, the crystal structure of the zebrafish P2X4 receptor has been solved, using protein expressed in insect cells.  This breakthrough demonstrates that using insect cells to express P2X receptors is feasible, and we aim to extend this work to more medically relevant mammalian P2X receptors, including rat P2X2 and human P2X4.

The main aim of the project is to develop two novel expression systems for mammalian P2X receptors in the fruit fly Drosophila melanogaster:

1. To produce large quantities of protein for crystal trials, we will over-express P2X receptors in the eyes of flies, an approach which has already been used successfully for the production of G-protein coupled receptors and membrane transporters, and has been demonstrated to result in improved protein quality compared to conventional insect cell expression systems.
2. To assay receptor function, we will express P2X receptors in sensory neurons.  This will enable us to assess the effects of mutations introduced into the receptors in order to optimise protein stability, a strategy commonly employed in order to increase the quality of membrane protein crystals.

This project offers the student an opportunity to perform ground-breaking research in the new and rapidly developing field of P2X receptor structural biology, generate novel expression systems and make significant advances in our understanding of the factors which govern P2X receptor expression and structure-function relationships.  During the course of these studies the student will learn and apply an array of techniques including molecular biology, Drosophila genetics, eukaryotic protein expression and electrophysiology.

Young, M. T. (2010) P2X receptors: dawn of the post-structure era. Trends in Biochemical Sciences. 35, 83-90

http://www.cardiff.ac.uk/biosi/contactsandpeople/stafflist/u-z/young-mark-dr-overview_new.html