2013 journal article
Phosphatidylinositol 4,5-Bisphosphate Influences PIN Polarization by Controlling Clathrin-Mediated Membrane Trafficking in Arabidopsis
PLANT CELL, 25(12), 4894–4911.
MeSH headings : Arabidopsis / cytology; Arabidopsis / genetics; Arabidopsis / growth & development; Arabidopsis / metabolism; Arabidopsis Proteins / analysis; Arabidopsis Proteins / metabolism; Biological Transport; Cell Polarity; Clathrin-Coated Vesicles / physiology; Endocytosis; Green Fluorescent Proteins / analysis; Indoleacetic Acids / metabolism; Membrane Transport Proteins / analysis; Membrane Transport Proteins / metabolism; Mutation; Phenotype; Phosphatidylinositol 4,5-Diphosphate / physiology; Phosphotransferases (Alcohol Group Acceptor) / genetics
open access via www.plantcell.org (publisher PDF)
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2. Zero Hunger
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13. Climate Action
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Source: Web Of Science
Added: August 6, 2018
AbstractThe 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.