Stress signaling in Drosophila

Cells commonly use multiprotein kinase cascades to signal information from the cell membrane to the nucleus. Several conserved signaling pathways rela ted to the mitogen activated protein kinase (MAPK) pathway allow cells to r espond to normal developmental signals as well as signals produced under st ressful conditions. Genetic and molecular studies in Drosophila melanogaste r over the last several years have related that components of stress signal ing pathways, namely the Jun kinase (JNK) and p38 kinase signaling modules, are functionally conserved and participate in numerous processes during no rmal development. Specifically, the JNK pathway is required for morphogenet ic movements in embryogenesis and generation of tissue polarity in the adul t. The role of the p38 pathway in generation of axial polarity during oogen esis has been inferred from phenotypic analysis of mutations in the Drosoph ila homolog of DMKK3. In addition to their requirement for normal developme nt, cell culture and genetic investigations point to a role for both the (J NK) and p38 pathways in regulation of the immune response in the fly. This review details the known components of stress signaling pathways in Drosoph ila and recent insights into how these pathways are used and regulated duri ng development and homeostasis.