To survive, cells and organisms must be able to change their behavior in response to multiple
environmental cues delivered at the same time. The proteins involved in this process are organized in
pathways, that can be likened to family groups or groups working together to achieve a specific
outcome; and these pathways, in turn, interact with other parallel pathways, in a kind of large social
network that integrates and modulates the overall biological outcome. A breach in signal fidelity, a
change in signal strength, or failure to integrate parallel pathways can have dire consequences for cells
and tissues, causing developmental defects and/or disease. Fine-tuning is key, and often pathways
synergize or antagonize each other depending on the biological system. We will investigate how MEK1, a
component of a conserved signaling cascade activated downstream of the most potent human
oncogene, integrates pathways leading to proliferation, differentiation and quiescence.