GSBS Student Publications


MOM-4, a MAP kinase kinase kinase-related protein, activates WRM-1/LIT-1 kinase to transduce anterior/posterior polarity signals in C. elegans

UMMS Affiliation

Graduate School of Biomedical Sciences; Program in Molecular Medicine



Document Type


Medical Subject Headings

Amino Acid Sequence; Animals; Body Patterning; Caenorhabditis elegans; *Caenorhabditis elegans Proteins; Conserved Sequence; Cytoskeletal Proteins; DNA-Binding Proteins; Embryo, Nonmammalian; Endoderm; Enzyme Activation; Helminth Proteins; High Mobility Group Proteins; Membrane Proteins; Molecular Sequence Data; Phosphorylation; Protein-Serine-Threonine Kinases; Sequence Alignment; Sequence Homology, Amino Acid; Signal Transduction; Transcription Factors


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.

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Citation: Mol Cell. 1999 Aug;4(2):275-80.

Related Resources

Link to Article in PubMed

Journal Title

Molecular cell

PubMed ID