In order to survive living cells need to sense and respond to changes in their environment. Cells detect, integrate and transmit multiple extracellular signals using protein-based biochemical circuits. Multiple gene expression processes can be altered as a result. Adaptational changes then lead to new cell phenotypes that determine cells functioning. A set of biochemical reactions that deal with signal detection, transduction and decision making is often considered as cellular information processing. In our group we use a variety of theoretical and experimental approaches to provide a deeper understanding of principles that govern biochemical communication.