The mammalian mitogen activated protein kinase network.

The families ofMAP kinases cascades (mitogen activated protein kinases) form major signalling systems by which cells transduce extracellular signals into cellular responses. Studying the regulation of these MAP kinase signalling pathways is of utmost importance in the understanding of the triggering of cell proliferation versus cell differentiation and the responses of the cell to stress or osmotic factors. This review will describe in detail the archetypal MAP kinase cascade (Raf-MEKERK); it will present the more recently discovered MAP kinase cascades (SAPK and p38) and provide some indications on the regulation of this network of signalling pathways. The scope of the review is not to provide an exhaustive listing of all aspects of research in this field; it aims rather to provide a basis for readers unfamiliar with the subject to scrutinise specific points of interest. Special attention will be given to introduce clearly the nomenclature of mammalian MAP kinase cascades, since it is often confusing with up to five names being used for the same mammalian enzyme. Readers requiring more detailed information on the MAP kinase cascades are referred to other recent reviews. 1-5