title: Interactions of PIN and PGP auxin transport mechanisms.
abstract: Polarized transport of the plant hormone auxin influences multiple growth processes in plants and is regulated by plasma-membrane-localized efflux and uptake carriers. The PGP (P-glycoprotein) ABC transporters (ATP-binding-cassette transporters), PIN (pin-formed) subfamily of major facilitator proteins and members of AUX/LAX families have been shown to independently transport auxin both in planta and in heterologous systems. However, PIN- and PGP-mediated transport in heterologous systems exhibits decreased substrate specificity and inhibitor-sensitivity compared with what is seen in plants and plant cells. To determine whether PIN-PGP interactions enhance transport specificity, we analysed interactions of the representative auxin-transporting PGPs with PIN1 and AUX1 in planta and in heterologous systems. Here, we provide evidence that PINs and PGPs interact and function both independently and co-ordinately to control polar auxin transport and impart transport specificity and directionality. These interactions take place in protein complexes stabilized by PGPs in detergent-resistant microdomains.
authors.affiliation: Department of Horticulture, Purdue University, West Lafayette, IN 47907-2010, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bandyopadhyay
authors.forename: J J
authors.initials: JJ
authors.lastname: Blakeslee
authors.forename: O R
authors.initials: OR
authors.lastname: Lee
authors.forename: J
authors.initials: J
authors.lastname: Mravec
authors.forename: M
authors.initials: M
authors.lastname: Sauer
authors.forename: B
authors.initials: B
authors.lastname: Titapiwatanakun
authors.forename: S N
authors.initials: SN
authors.lastname: Makam
authors.forename: R
authors.initials: R
authors.lastname: Bouchard
authors.forename: M
authors.initials: M
authors.lastname: Geisler
authors.forename: E
authors.initials: E
authors.lastname: Martinoia
authors.forename: J
authors.initials: J
authors.lastname: Friml
authors.forename: W A
authors.initials: WA
authors.lastname: Peer
authors.forename: A S
authors.initials: AS
authors.lastname: Murphy
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000737:chemistry / Q000378:metabolism*; D008027:Light; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008954:Models, Biological; D010937:Plant Growth Regulators; D018521:Plant Physiological Phenomena
chemical_list: D018528:ATP-Binding Cassette Transporters; C114215:ATPGP1 protein, Arabidopsis; C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D010937:Plant Growth Regulators