Red Cell Membranes and Sodium-Potassium Leaks The work in this lab concerns the movements of salt atoms, sodium and potassium, across the red cell membrane. As in all other human cells, the membrane of the red cell encloses a concentrated solution of proteins and metabolites which attracts water into the cell by osmosis. If not countered, this osmotic force will make the cell swell and burst. The cell offsets this osmotic effect by pumping sodium out of the cell, maintaining a small net deficit of sodium+potassium inside the cell that keeps it stable. The pump that does this works against a ‘leak’ process which cannot be too big, or else the pump cannot cope and the cell bursts. There is a series of human diseases, known as the ‘hereditary stomatocytoses’, in which the leaks are abnormally large, such that the red cells rupture prematurely, causing ‘haemolytic anaemia’. In our work we seek to understand the nature of these conditions. Among many others, we collaborate with Dr Lesley Bruce at the Bristol Institute for Transfusion Sciences, Bristol.