title: The C. elegans vulval induction gene lin-2 encodes a member of the MAGUK family of cell junction proteins.
abstract: The lin-2 gene is required for the induction of the Caenorhabditis elegans vulva. Vulval development is initiated by a signal from the anchor cell that is transduced by a receptor tyrosine kinase/Ras pathway. We show that lin-2 acts in the vulval precursor cell P6.p, downstream of lin-3 EGF and upstream of let-60 ras, to allow expression of the 1 degrees cell fate. lin-2 encodes a protein of relative molecular mass 109,000 (LIN-2A) with regions of similarity to CaM kinase II and membrane-associated guanylate kinases. Mutant lin-2 transgenes designed to lack either protein kinase or guanylate kinase activity are functional, indicating that LIN-2A has a structural rather than an enzymatic role in vulval induction. Most or all identified membrane-associated guanylate kinases are components of cell junctions, including vertebrate tight junctions and arthropod septate junctions in epithelia. Thus, LIN-2A may be a component of the cell junctions of the epithelial vulval precursor cells that is required for signaling by the receptor tyrosine kinase LET-23. We propose that LIN-2A is required for the localization of one or more signal transduction proteins (such as LET-23) to either the basal membrane domain or the cell junctions, and that mislocalization of signal transduction proteins in lin-2 mutants interferes with vulval induction.
authors.affiliation: Department of Developmental Biology, Stanford University Medical School, CA 94305, USA.
authors.forename: R
authors.initials: R
authors.lastname: Hoskins
authors.forename: A F
authors.initials: AF
authors.lastname: Hajnal
authors.forename: S A
authors.initials: SA
authors.lastname: Harp
authors.forename: S K
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018509:DNA, Helminth / Q000235:genetics; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D017238:Genes, Helminth; D011905:Genes, ras; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D007365:Intercellular Junctions / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013234:Stem Cells / Q000378:metabolism; D014844:Vulva / Q000254:growth & development* / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D018509:DNA, Helminth; D015801:Helminth Proteins; C097978:Lin-2 protein, C elegans; D008565:Membrane Proteins; D012333:RNA, Messenger; D066246:ErbB Receptors; C085873:let-23 protein, C elegans