In this talk I will present results and ongoing work of two interdisciplinary collaborations where we investigate essential generic features of eukaryotic cells.

Cells are able to sense their actual size and based on environmental inputs set a critical size to reach before they go through cell division. Such cell size control is inevitable to maintain cell size homeostasis from generation to generation. It is a long standing mystery how environment and size sensing mechanisms are coupled to sustain a proper size control system. Quite a few molecules were associated with this control in yeasts and recent discoveries led to several hypotheses that we turned into computational models. We used the models to explain why critical size linearly correlates with growth rate and they provided several predictions that were experimentally tested in collaborating laboratories.

All cells – including those in our body – possess some degree of asymmetry or ‘polarity’, which is key to their healthy function and if disrupted can lead to serious cellular malfunctions like those found in cancer. We have reconstructed with unprecedented spatiotemporal resolution the molecular networks that regulate cell polarity using an interdisciplinary strategy – combining genetics, microscopy and computational approaches – and focusing on the polarity machinery of the archetypal model organism Schizosaccharomyces pombe (fission yeast). We determined the detailed network topology and the functional hierarchy among polarity regulators in this species and incorporated these results into a mathematical model that captures the polarity pattern changes throughout the cell cycle of fission yeast cells.