title: MAP kinase signaling antagonizes PAR-1 function during polarization of the early Caenorhabditis elegans embryo.
abstract: PAR proteins (partitioning defective) are major regulators of cell polarity and asymmetric cell division. One of the par genes, par-1, encodes a Ser/Thr kinase that is conserved from yeast to mammals. In Caenorhabditis elegans, par-1 governs asymmetric cell division by ensuring the polar distribution of cell fate determinants. However the precise mechanisms by which PAR-1 regulates asymmetric cell division in C. elegans remain to be elucidated. We performed a genomewide RNAi screen and identified six genes that specifically suppress the embryonic lethal phenotype associated with mutations in par-1. One of these suppressors is mpk-1, the C. elegans homolog of the conserved mitogen activated protein (MAP) kinase ERK. Loss of function of mpk-1 restored embryonic viability, asynchronous cell divisions, the asymmetric distribution of cell fate specification markers, and the distribution of PAR-1 protein in par-1 mutant embryos, indicating that this genetic interaction is functionally relevant for embryonic development. Furthermore, disrupting the function of other components of the MAPK signaling pathway resulted in suppression of par-1 embryonic lethality. Our data therefore indicates that MAP kinase signaling antagonizes PAR-1 signaling during early C. elegans embryonic polarization.
authors.affiliation: Swiss Federal Institute of Technology, Institute of Biochemistry, ETH Hönggerberg, 8093 Zürich, Switzerland.
authors.forename: Annina C
authors.initials: AC
authors.lastname: Spilker
authors.forename: Alexia
authors.initials: A
authors.lastname: Rabilotta
authors.forename: Caroline
authors.initials: C
authors.lastname: Zbinden
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Labbé
authors.forename: Monica
authors.initials: M
authors.lastname: Gotta
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity / Q000235:genetics / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D004843:Epistasis, Genetic; D049751:Genome, Helminth / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000235:genetics / Q000502:physiology; D018613:Microscopy, Confocal; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
chemical_list: D029742:Caenorhabditis elegans Proteins; C409406:PAR-1 protein, C elegans; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; C085697:mpk-1 protein, C elegans