Plant ATP-Binding Cassette Transporters Philip A. Rea Plant Science Institute, Department of Biology, Carolyn Hoff Lynch Biology Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018; email: parea@sas.upenn.edu Annu. Rev. Plant Biol. 2007. 58:347–75 The Annual Review of Plant Biology is online at plant.annualreviews.org This article’s doi: 10.1146/annurev.arplant.57.032905.105406 Copyright c  2007 by Annual Reviews. All rights reserved First published online as a Review in Advance on January 29, 2007 1543-5008/07/0602-0347$20.00 Key Words subfamilies, organization, functions, localization Abstract The ATP-binding cassette (ABC) protein superfamily is one of the largest known, with over 120 members in both Arabidopsis thaliana and rice (Oryza sativa). Most, but not all, ABC proteins are modu- larly organized membrane proteins (“ABC transporters”) that me- diate MgATP-energized transmembrane transport and/or regulate other transporters. The range of processes in which members of the various subclasses of plant ABC transporters have been impli- cated encompasses polar auxin transport, lipid catabolism, xenobiotic detoxification, disease resistance, and stomatal function. Although it is often possible to predict the likely function of a plant ABC trans- porter on the basis of its subfamily membership, there are many whose capabilities deviate from what would be predicted from the properties of even their most sequence-related counterparts. When taking account of this and the disparate processes in which the few that have been characterized participate, it is likely that elucidation of the mechanistic basis of any given plant process will necessitate consideration of at least one ABC transporter. 347 Annu. Rev. Plant Biol. 2007.58:347-375. Downloaded from arjournals.annualreviews.org by UNIVERSITY OF PENNSYLVANIA LIBRARY on 05/04/07. For personal use only.