Our strategy of choice is a combination of the so-called âtop-downâ and âbottom-upâ approaches, where the aim is to de-convolve complex interdependencies of local biochemical and biophysical processes by identifying the key interactions and their constraints. Once recognized, the essential elements become the foundation of simplified models. To quantitatively understand these models, we combine approximate analytical and numerical approaches with a range of simulation techniques, out of which Langevin simulations, Monte Carlo, Molecular Dynamics as well as Rigid Body and Lattice Boltzmann simulations are part of the everyday research in the group. Successful theoretical modelling necessitates input from experiments. In this way, the relevant models are constructed and verified which prompts further theoretical reasoning. Furthermore, the small models may point out regulatory mechanisms relevant to biochemical signaling and macroscopic behaviour, which may be tested in the biological context on the level of a single cell, but also in tissue development.