Efflux carriers

Another area in which Arabidopsis genetics is proving to be useful is the study of the proposed role of flavonoids in regulating auxin transport. Several years ago, Jacobs and Rubery published the first evidence that flavonoids could specifically compete with naphthylphthalamic acid for binding to the auxin efflux carrier in etiolated zucchini hypocotyls.35 This finding was somewhat controversial, however, and no additional evidence for the connection between flavonoids and auxin transport was reported for some time. Brown et al. have now used Arabidopsis flavonoid mutants to generate new evidence in support of a role for flavonoids in the regulation of polar auxin movement.6 These experiments took... 

Deferme S, Van Gelder J, Augustijns P (2002a) Inhibitory effects of fruit extracts on P-glycoprotein-related efflux carriers An in-vitro screening. J Pharm Pharmacol 54 1-7. 

Mols R, Deferme S, Augustijns P (2005) Sulfasalazine transport in in-vitro, ex-vivo and in-vivo absorption models contribution of efflux carriers and their modulation by co-administration of synthetic nature-identical fruit extracts. J Pharm Pharmacol 57 1565-1573. 

Steinmann, T., Geldner, N., Grebe, M. et al. (1999). Coordinated polar localization of auxin efflux carrier PINl by GNOM ARF GEE Science, 286,316-318. 

Li ZS, Alfenito M, Rea PA, et al. (1997) Vacuolar uptake of die phytoalexin medicarpin by the glutathione conjugate pump. Phytochemistiy 45 689-693 Li L, He Z, Pandey GK, et al. (2002) Functional cloning and characterization of a plant efflux carrier for multidrug and heavy metal detoxification. J Biol Chem 277 5360-5368 Li ZS, Szczypka M, Lu YP, et al. (1996) The yeast cadmium factor protein (YCFl) is a vacuolar glutathione S-conjugate pump. J Biol Chem 271 6509-6517... 

Fig. 22.3 Consensus effects of Spd and Spm on auxin metabolism and signaling cascade. Description is same as in legends to Fig. 22.1. AFB2 auxin signaling F-box protein 2, ARFs auxin response factors, Awc/IAA indole-3-acetic acid inducible (members of Aux/IAA protein family), AuxRE auxin response cu-elements, GH3 lAA-amido synthetase, lAMTl lAA carboxyl methyl transferase 1, ILL4 lAA amidohydrolase, LAX3 like AUXl 3, PGP 10 P-glycoprotein 10 (auxin efflux carrier), PINl PIN-formed 1, PINS PIN-formed 5, TIRl transport inhibitor response 1, YUC YUCCA...

Distribution of auxin and establishment of its gradient within tissues is crucial for some of the auxin-regulated plant growth and development processes (Ikeda et al. 2009 Tivendale et al. 2014 van Berkel et al. 2013). Several auxin influx and efflux carriers have been characterized that regulate cell-to-cell transport of auxin. Auxin influx into the cell is either passive or regulated by AUXl/LAX (auxin per-mease/like AUX) family of H+ symporters (Pattison and Catala 2012 Peret et al. 

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