Biophysics of Nanoscale Signalling Systems

We have a long standing interest in local calcium signalling in cardiac muscle. The term local refers to the fact that the critical signalling distances are often in the 10 nm range. Of particular interest is the cardiac ryanodine receptor (RyR) that is typically forming clusters within specialised structures, tight membrane spaces referred to as junctions. The RyR is a truly gigantic protein, a homo-tetramer of a 500 kD subunit and approximately 30 nm in size. A lot of our recent work has been concentrating on how to monitor the nanoscale arrangement of RyRs and associated proteins in cardiac myocytes.

Advanced Fluorescence Imaging

We work on several types of advanced fluorescence imaging, including single molecule localisation microscopy (SMLM), Airy Scan Microscopy (aka Image Scanning Microscopy), and fluorescence microscopy in strongly scattering samples.

Quantitative Super-Resolution Imaging

We have been working with super-resolution imaging modalities for a number of years now. Biophysical insight often critically depends on quantitative knowledge of protein and molecule numbers. Advanced fluorescence imaging now has a number of ways in which Quantitative Imaging can be achieved and we have been pushing the technology to enable this routinely, using localisation microscopy, especially DNA-PAINT, and x-ray microscopy.

Other Advanced Imaging Approaches

We are also pursuing some other aspects of advanced imaging. We are working with Alex Corbett on the use of deformable mirrors, primarily to modulate our microscope point-spread functions. In conjunction with Jacopo Bertolotti we have recently started to investigate new methods to image in deeply scattering samples which is an exciting area of microscopy with a lot of potential.

Mathematical Modelling of Nanoscale Calcium Dynamics

Mathematical modelling is critical to make the connection between the protein distributions that we record using our imaging experiments and the functional calcium signalling in intact cells. We have been closely working with our colleagues Vijay Rajagopal, head of the Cell Structure and Mechanobiology Group, and Edmund Crampin, Chair of Systems Biology at the University of Melbourne. A major goal is the automatic model construction from multi-modal 3D imaging data (such as electron microscopy tomography, confocal fluorescence and super-resolution microscopy).