Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux.
In plants, cell polarity and tissue patterning are connected by intercellular flow of the phytohormone auxin, whose directional signaling depends on polar subcellular localization of PIN auxin transport proteins. The mechanism of polar targeting of PINs or other cargos in plants is largely unidentified, with the PINOID kinase being the only known molecular component. Here, we identify PP2A phosphatase as an important regulator of PIN apical-basal targeting and auxin distribution. Genetic analysis, localization, and phosphorylation studies demonstrate that PP2A and PINOID both partially colocalize with PINs and act antagonistically on the phosphorylation state of their central hydrophilic loop, hence mediating PIN apical-basal polar targeting. Thus, in plants, polar sorting by the reversible phosphorylation of cargos allows for their conditional delivery to specific intracellular destinations. In the case of PIN proteins, this mechanism enables switches in the direction of intercellular auxin fluxes, which mediate differential growth, tissue patterning, and organogenesis.
Michniewicz
Marta
M
Zentrum für Molekularbiologie der Pflanzen, Universität Tübingen, Tübingen, Germany.
Zago
Marcelo K
MK
Abas
Lindy
L
Weijers
Dolf
D
Schweighofer
Alois
A
Meskiene
Irute
I
Heisler
Marcus G
MG
Ohno
Carolyn
C
Zhang
Jing
J
Huang
Fang
F
Schwab
Rebecca
R
Weigel
Detlef
D
Meyerowitz
Elliot M
EM
Luschnig
Christian
C
Offringa
Remko
R
Friml
Jirí
J
D017360:Arabidopsis / Q000196:embryology / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity; D011992:Endosomes / Q000378:metabolism; D005838:Genotype; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018519:Meristem / Q000201:enzymology / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D030821:Plants, Genetically Modified / Q000196:embryology / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000378:metabolism; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D010749:Phosphoprotein Phosphatases; D017346:Protein Serine-Threonine Kinases; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; C116363:PIN1 protein, Arabidopsis; C117013:AT5G57090 protein, Arabidopsis; C451260:PIN4 protein, Arabidopsis; C405165:PINOID protein, Arabidopsis