Spatio-temporal Molecular Membrane Dynamics and Signal Transduction Processes in Live Cells
Previous and current research
Membrane fusion and fission are universal events that occur in the functioning of living organisms. The biological membranes that enclose and subdivide cells into functional organelles and vesicles are composed of proteins and phospholipids. Much work has focused on the proteins in membrane vesicles and the role they play in the fission and fusion of vesicles. However, it has become clear recently that the phospholipids in membranes play an equally important role in the signalling and the physical processes involved in vesicle dynamics.
Phospholipid composition is important for defining membrane curvature, decreasing cohesive forces and favouring fusion. Localised changes in phospholipid content in the membrane induce fusion of the bilayer by destabilising the secondary structure of lipid bilayers, and promoting non-lamellar phases that favour fusion. One of the key projects in the Biophysics Laboratory is to investigate lipid sorting and distribution in particular vesicular compartments of different biological systems. Various in vitro studies and models have depicted the mechanisms of membrane fusion but to date these mechanisms have not been followed in vivo. We intend to exploit the application of fluorescence resonance energy transfer measured by FLIM to measure the kinetics and spatio-temporal relationship of fusion between membranes.
Mitosis is a highly regulated element of cell division. The associated processes of nuclear envelope breakdown and its re-assembly following mitosis are essential membrane reorganisation events. We are applying the methodologies available for the study of membrane dynamics to understand how the nuclear envelope reforms. This involves the use of a sea urchin cell free system, which can fully reconstitute envelope formation.
