The c-Jun N-terminal kinase (JNK) and
p38 MAP kinase (MAPK) pathways are involved in various stress responses and apoptosis. In mammal, JNK is activated by MKK7 and MKK4 MAPK kinases (MAPKKs) and
p38 is activated by MKK3, MKK4 and MKK6 MAPKKs. These members of the MAPKK superfamily are activated by members of MAPKKK superfamily such as MEKK, TAK1, MLK, TAO and ASK1. Although these pathways have been implicated in the response to stresses and inflammation, the physiological roles of the JNK and
p38 pathways in the normal development and function of the organism is less well understood. In C. elegans, several mutants corresponding to the components of JNK/p38 cascades have been isolated:
jnk-1 (JNK homolog),
jkk-1 (MKK7 homolog),
sek-1 (MAPKK),
mek-1 (MAPKK),
mom-4 (TAK1 homolog) and
nsy-1 (ASK1 homolog). The C.elegans genome project shows that there are at least seven members of the MAPKKK superfamily, five members of the MAPKK superfamily and seven members of the MAPK superfamily in C.elegans. To investigate the roles of these components and the relationships among them, we isolated several deletion mutants of these genes. Analysis of these mutants will be discussed.