MOM-4, a MAP kinase kinase kinase-related protein, activates WRM-1/LIT-1 kinase to transduce anterior/posterior polarity signals in C. elegans
Graduate School of Biomedical Sciences; Program in Molecular Medicine
Life Sciences | Medicine and Health Sciences
In C. elegans, a Wnt/WG-like signaling pathway down-regulates the TCF/LEF-related protein, POP-1, to specify posterior cell fates. Effectors of this signaling pathway include a beta-catenin homolog, WRM-1, and a conserved protein kinase, LIT-1. WRM-1 and LIT-1 form a kinase complex that can directly phosphorylate POP-1, but how signaling activates WRM-1/LIT-1 kinase is not yet known. Here we show that mom-4, a genetically defined effector of polarity signaling, encodes a MAP kinase kinase kinase-related protein that stimulates the WRM-1/LIT-1-dependent phosphorylation of POP-1. LIT-1 kinase activity requires a conserved residue analogous to an activating phosphorylation site in other kinases, including MAP kinases. These findings suggest that anterior/posterior polarity signaling in C. elegans may involve a MAP kinase-like signaling mechanism.
Mol Cell. 1999 Aug;4(2):275-80.
Shin, Tae Ho; Yasuda, Jun; Rocheleau, Christian Ernest; Lin, Rueyling; Soto, Martha C.; Bei, Yanxia; Davis, Roger J.; and Mello, Craig C., "MOM-4, a MAP kinase kinase kinase-related protein, activates WRM-1/LIT-1 kinase to transduce anterior/posterior polarity signals in C. elegans" (1999). GSBS Student Publications. 1109.