title: Par-1 regulates stability of the posterior determinant Oskar by phosphorylation.
abstract: Par-1 kinase is critical for polarization of the Drosophila melanogaster oocyte and the one-cell Caenorhabditis elegans embryo. Although Par-1 localizes specifically to the posterior pole in both cells, neither its targets nor its function at the posterior pole have been elucidated. Here we show that Drosophila Par-1 phosphorylates the posterior determinant Oskar (Osk) and demonstrate genetically that Par-1 is required for accumulation of Osk protein. We show in cell-free extracts that Osk protein is intrinsically unstable and that it is stabilized after phosphorylation by Par-1. Our data indicate that posteriorly localized Par-1 regulates posterior patterning by stabilizing Osk.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 10.2209, D-69012 Heidelberg, Germany.
authors.forename: Veit
authors.initials: V
authors.lastname: Riechmann
authors.forename: Gustavo J
authors.initials: GJ
authors.lastname: Gutierrez
authors.forename: Paolo
authors.initials: P
authors.lastname: Filardo
authors.forename: Angel R
authors.initials: AR
authors.lastname: Nebreda
authors.forename: Anne
authors.initials: A
authors.lastname: Ephrussi
mesh_terms: D020413:3' Untranslated Regions / Q000378:metabolism; D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000196:embryology / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D003546:Cysteine Endopeptidases / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000378:metabolism; D010053:Ovary / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014020:Tissue Extracts / Q000737:chemistry / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; D029721:Drosophila Proteins; D009097:Multienzyme Complexes; D011993:Recombinant Fusion Proteins; D014020:Tissue Extracts; D025801:Ubiquitin; C091675:osk protein, Drosophila; C409406:PAR-1 protein, C elegans; D017346:Protein Serine-Threonine Kinases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex