RTK/Ras/MAPK signaling pathway

Receptor Tyrosine Kinase (RTK)/Ras GTPase/MAP kinase (MAPK) activated signaling pathways are used repeatedly during metazoan development to control many different biological processes. C. elegans contains two different RTKs (LET-23/EGFR and EGL-15 /FGFR) that are known to stimulate LET-60/Ras and a MAPK cascade consisting of the kinases LIN-45/Raf, MEK-2/MEK and MPK-1/ERK. This Ras/MAPK cascade is required for multiple developmental events, including induction of vulval, uterine, spicule, P12 and excretory duct cell fates, control of sex myoblast migration and axon guidance, and promotion of germline meiosis. Studies in C. elegans have provided much insight into the basic framework of this RTK/Ras/MAPK signaling pathway, its regulation, how it elicits cell-type specific responses, and how it interacts with other signaling pathways such as the Wnt and Notch pathways.

Post-transcriptional RNA binding

Post-transcriptional control of RNA metabolism plays a major role in development and involves proteins that bind to RNA (RBPs). RBP binding has been shown to display tissue-specific activity, which when altered can result in tissue-specific mutant phenotypes. Molecular studies have identified many RBPs that bind regulatory sequences in the 3' untranslated regions of mRNAs. Studies of RBPs in C. elegans seek to provide insights into how RBPs exert coordinate control of their RNA targets and affect development.