We are interested in life processes that involve deformation and remodeling of membranes, such as viral infection, cell-cell fusion in fertilization, and secretion of neurotransmitters by exocytosis. In order to gain insight into membrane remodeling in such processes, we use mechanical single-molecule techniques: Optical Tweezers in combination with confocal fluorescence microscopy and Atomic Force Microscopy (AFM). Our research is highly multidisciplinary, combining Biology, Chemistry, Physics and some engineering to modify our tools according to the experimental needs, and we also work in close collaboration with biologists and theorists. Our tools allow us to measure membrane mechanical properties and to explore the interactions between membranes and proteins in bio-mimetic model systems and cells. By such quantitative measurements, we hope to contribute to the understanding of biological processes in which membranes play a central role.