Specific Adsorption of Annexin A1 on Solid Supported Membranes: A Model Study

Abstract

The quartz crystal microbalance (QCM) is an invaluable tool to monitor protein-membrane and membrane-membrane interactions mediated by proteins without labeling one of the components. In this chapter we show that the formation process of solid supported membranes by spreading and fusion of lipid vesicles can be readily followed by the QCM technique, and that Monte Carlo simulations allow for a detailed modeling of the process. We further demonstrate that only membranes attached to a solid support make it possible to separate the two binding modes of annexin A1 to membranes, hence allowing a quantitative analysis of the two processes. By monitoring the changes in the resonance frequency of 5-MHz quartz plates combined with Monte Carlo simulations, the kinetics of the annexin A1-membrane interaction can be followed in detail, which contributes to the biological understanding of annexin A1 function in the cell. The simultaneous readout of the change in resonance frequency and dissipation allows one to follow the binding of lipid vesicles, the second membrane binding process, to membrane-bound annexin A1, which gives information on the impact of different parameters, such as the N-terminus of annexin A1 and the protein surface coverage.