title: Phosphatidylinositol 4,5-bisphosphate influences PIN polarization by controlling clathrin-mediated membrane trafficking in Arabidopsis.
abstract: The functions of the minor phospholipid phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] during vegetative plant growth remain obscure. Here, we targeted two related phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) PIP5K1 and PIP5K2, which are expressed ubiquitously in Arabidopsis thaliana. A pip5k1 pip5k2 double mutant with reduced PtdIns(4,5)P2 levels showed dwarf stature and phenotypes suggesting defects in auxin distribution. The roots of the pip5k1 pip5k2 double mutant had normal auxin levels but reduced auxin transport and altered distribution. Fluorescence-tagged auxin efflux carriers PIN-FORMED (PIN1)-green fluorescent protein (GFP) and PIN2-GFP displayed abnormal, partially apolar distribution. Furthermore, fewer brefeldin A-induced endosomal bodies decorated by PIN1-GFP or PIN2-GFP formed in pip5k1 pip5k2 mutants. Inducible overexpressor lines for PIP5K1 or PIP5K2 also exhibited phenotypes indicating misregulation of auxin-dependent processes, and immunolocalization showed reduced membrane association of PIN1 and PIN2. PIN cycling and polarization require clathrin-mediated endocytosis and labeled clathrin light chain also displayed altered localization patterns in the pip5k1 pip5k2 double mutant, consistent with a role for PtdIns(4,5)P2 in the regulation of clathrin-mediated endocytosis. Further biochemical tests on subcellular fractions enriched for clathrin-coated vesicles (CCVs) indicated that pip5k1 and pip5k2 mutants have reduced CCV-associated PI4P 5-kinase activity. Together, the data indicate an important role for PtdIns(4,5)P2 in the control of clathrin dynamics and in auxin distribution in Arabidopsis.
authors: Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, 37077 Goettingen, Germany.
authors: Till
authors: T
authors: Ischebeck
authors: Stephanie
authors: S
authors: Werner
authors: Praveen
authors: P
authors: Krishnamoorthy
authors: Jennifer
authors: J
authors: Lerche
authors: Mónica
authors: M
authors: Meijón
authors: Irene
authors: I
authors: Stenzel
authors: Christian
authors: C
authors: Löfke
authors: Theresa
authors: T
authors: Wiessner
authors: Yang Ju
authors: YJ
authors: Im
authors: Imara Y
authors: IY
authors: Perera
authors: Tim
authors: T
authors: Iven
authors: Ivo
authors: I
authors: Feussner
authors: Wolfgang
authors: W
authors: Busch
authors: Wendy F
authors: WF
authors: Boss
authors: Thomas
authors: T
authors: Teichmann
authors: Bettina
authors: B
authors: Hause
authors: Staffan
authors: S
authors: Persson
authors: Ingo
authors: I
authors: Heilmann
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism; D001692:Biological Transport; D016764:Cell Polarity; D022163:Clathrin-Coated Vesicles / Q000502:physiology*; D004705:Endocytosis; D049452:Green Fluorescent Proteins / Q000032:analysis; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000032:analysis / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000502:physiology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D049452:Green Fluorescent Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C116363:PIN1 protein, Arabidopsis; C117013:AT5G57090 protein, Arabidopsis; C020077:1-phosphatidylinositol-4-phosphate 5-kinase