title: Regulation of ABCB1/PGP1-catalysed auxin transport by linker phosphorylation.
abstract: Polar transport of the plant hormone auxin is controlled by PIN- and ABCB/PGP-efflux catalysts. PIN polarity is regulated by the AGC protein kinase, PINOID (PID), while ABCB activity was shown to be dependent on interaction with the FKBP42, TWISTED DWARF1 (TWD1). Using co-immunoprecipitation (co-IP) and shotgun LC-MS/MS analysis, we identified PID as a valid partner in the interaction with TWD1. In-vitro and yeast expression analyses indicated that PID specifically modulates ABCB1-mediated auxin efflux in an action that is dependent on its kinase activity and that is reverted by quercetin binding and thus inhibition of PID autophosphorylation. Triple ABCB1/PID/TWD1 co-transfection in tobacco revealed that PID enhances ABCB1-mediated auxin efflux but blocks ABCB1 in the presence of TWD1. Phospho-proteomic analyses identified S634 as a key residue of the regulatory ABCB1 linker and a very likely target of PID phosphorylation that determines both transporter drug binding and activity. In summary, we provide evidence that PID phosphorylation has a dual, counter-active impact on ABCB1 activity that is coordinated by TWD1-PID interaction.
authors.affiliation: Molecular Plant Physiology, Institute of Plant Biology, University of Zurich and Zurich-Basel Plant Science Center, Zurich, Switzerland.
authors.forename: Sina
authors.initials: S
authors.lastname: Henrichs
authors.forename: Bangjun
authors.initials: B
authors.lastname: Wang
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Fukao
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Zhu
authors.forename: Laurence
authors.initials: L
authors.lastname: Charrier
authors.forename: Aurélien
authors.initials: A
authors.lastname: Bailly
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Oehring
authors.forename: Miriam
authors.initials: M
authors.lastname: Linnert
authors.forename: Matthias
authors.initials: M
authors.lastname: Weiwad
authors.forename: Anne
authors.initials: A
authors.lastname: Endler
authors.forename: Paolo
authors.initials: P
authors.lastname: Nanni
authors.forename: Stephan
authors.initials: S
authors.lastname: Pollmann
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancuso
authors.forename: Alexander
authors.initials: A
authors.lastname: Schulz
authors.forename: Markus
authors.initials: M
authors.lastname: Geisler
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D040901:Proteomics; D011794:Quercetin / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism; D014026:Nicotiana / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; C114215:ATPGP1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010750:Phosphoproteins; C471286:TWD1 protein, Arabidopsis; D011794:Quercetin; C405165:PINOID protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D022021:Tacrolimus Binding Proteins