REGULATION OF GENE-EXPRESSION BY SERINE THREONINE PROTEIN PHOSPHATASES/

The activation of signal transduction pathways by extracellular stimul i, such as growth factors or hormones, ultimately results in changes i n the expression of specific genes. The altered pattern of expression eventually determines the resulting cellular consequences, e.g. cell g rowth, division, or differentiation. It has been well established that the reversible phosphorylation of proteins is a major regulatory mech anism in these processes. However, while much has been learned about t he role of kinases, the involvement of protein phosphatases is less cl ear and has only recently begun to be investigated in more detail. Thi s review will present some of the new findings that demonstrate a cruc ial regulatory function of serine/threonine protein phosphatases (PPas es) in gene regulatory processes.