Growth factors, growth inhibitors and cell cycle control (review)

Decisions about growth or quiescence are operated in the cells by a complex signal processing machinery. This machinery is built by a network of proteins that internalize these stimulatory signals from the extracellular environment across the plasmamembrane, through the cytoplasm and finally into the nucleus. Most of the information about the genes which encode the proteins that take part in this process have been obtained from studies of their aberrant alleles or oncogenes. It has become clear lately that the cell also processes negative feedback mechanisms to check this process so that it may operate error free.