An update on an energy-based multiscale modelling framework for physiology.

Bond graphs provide a useful level of abstraction for modelling protein function for a wide range of physiological processes, such as metabolic reactions, membrane transporters, ion channels, myofilament mechanics, receptors and signalling, etc. In this talk I will show how bond graph templates (that conserve mass, charge and energy, respectively) are developed for enzyme-catalysed metabolic reactions, the sodium-potassium ATPase pump, and some of the members of the SLC transporter superfamily (including glucose transport, glutamate transport, sodium-calcium exchange, and sodium-hydrogen exchange). These can be parameterised for a specific cell and tissue type for which the experimental kinetic data is available. I will also show how analytic expressions can be derived for a representative four- or six-state model, given reasonable assumptions associated with steady state flux conditions, while always preserving thermodynamic consistency. Finally, based on work with Weiwei Ai and David Nickerson (Andre), I will present details on fitting parameters for the glucose transporters to experimental data and show how well the steady state flux expressions match the full kinetic analysis.