Interactions of PIN and PGP auxin transport mechanisms

• Published in: Biochemical Society transactions Vol. 35; no. Pt 1; p. 137
• Main Authors: Bandyopadhyay, A, Blakeslee, J J, Lee, O R, Mravec, J, Sauer, M, Titapiwatanakun, B, Makam, S N, Bouchard, R, Geisler, M, Martinoia, E, Friml, J, Peer, W A, Murphy, A S
• Format: Journal Article
• Language: English
• Published: England 01-02-2007
• Subjects: Arabidopsis; Arabidopsis Proteins - metabolism; ATP-Binding Cassette Transporters - metabolism; Biological Transport; Gene Expression Regulation, Plant; Indoleacetic Acids - chemistry; Indoleacetic Acids - metabolism; Light; Membrane Transport Proteins - metabolism; Models, Biological; Plant Growth Regulators; Plant Physiological Phenomena
• ISSN: 0300-5127
• DOI: 10.1042/bst0350137

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.