ABSTRACT
Through large-scale analysis of human genes and the proteins they produce, a detailed map of the human body will provide a blueprint of molecular pathways, which will describe how the complicated interactions of proteins support our existence. A blueprint of this interdependent network is vital to the development of drugs that will be used to influence the quality of life through pharmaceutical intervention. Figure 4 represents a common molecular pathway that helps illustrate the dependency on many factors to respond to the extracellular signal provided by platelet-derived growth factor (PDGF). The final response to the envi-
ronmental signal is largely dependent on the abundance and state of the proteins the pathway. The lack of expression or the inactivation of the downstream proteins can lead to a breakdown in the communication of the signal or the diversion of the signal toward an alternative pathway.
