Each of our cells contains about 40 million proteins that together perform all the tasks the cell needs to survive. For a smooth action, the right proteins must be concentrated in specific amounts, at a specific time and at a specific location. However, establishing such a delicate distribution requires an extremely precise process, happening at tiny spatial resolutions that standard cell biology tools are often unable to detect. To understand how this mechanism works, researchers from the University of Geneva (UNIGE) developed a new approach combining genetics and cell biology experiments with physical modeling. Using specific algorithms, they simulated the formation of protein gradients in 3D and throughout time and were able to explain these complex mechanisms. Moreover, their innovative model can be adapted to other biology systems to investigate protein dynamics. These results can be read in the Proceedings of the National Academy of Sciences.