Roles of MAP kinase cascades in Caenorhabditis elegans.

Mitogen-activated protein kinases (MAPKs) are serine/threonine protein kinases that are activated by diverse stimuli such as growth factors, cytokines, neurotransmitters and various cellular stresses. MAPK cascades are generally present as three-component modules, consisting of MAPKKK, MAPKK and MAPK. The precise molecular mechanisms by which these MAPK cascades transmit signals is an area of intense research, and our evolving understanding of these signal cascades has been facilitated in great part by genetic analyses in model organisms. One organism that has been commonly used for genetic manipulation and physiological characterization is the nematode Caenorhabditis elegans. Genes sequenced in the C. elegans genome project have furthered the identification of components involved in several MAPK pathways. Genetic and biochemical studies on these components have shed light on the physiological roles of MAPK cascades in the control of cell fate decision, neuronal function and immunity in C. elegans.