RT Journal Article SR Electronic T1 PIN Proteins Perform a Rate-Limiting Function in Cellular Auxin Efflux JF Science JO Science FD American Association for the Advancement of Science SP 914 OP 918 DO 10.1126/science.1123542 VO 312 IS 5775 A1 Petrášek, Jan A1 Mravec, Jozef A1 Bouchard, Rodolphe A1 Blakeslee, Joshua J. A1 Abas, Melinda A1 Seifertová, Daniela A1 Wiśniewska, Justyna A1 Tadele, Zerihun A1 Kubeš, Martin A1 Čovanová, Milada A1 Dhonukshe, Pankaj A1 Skůpa, Petr A1 Benková, Eva A1 Perry, Lucie A1 Křeček, Pavel A1 Lee, Ok Ran A1 Fink, Gerald R. A1 Geisler, Markus A1 Murphy, Angus S. A1 Luschnig, Christian A1 Zažímalová, Eva A1 Friml, Jiří YR 2006 UL http://science.sciencemag.org/content/312/5775/914.abstract AB Intercellular flow of the phytohormone auxin underpins multiple developmental processes in plants. Plant-specific pin-formed (PIN) proteins and several phosphoglycoprotein (PGP) transporters are crucial factors in auxin transport–related development, yet the molecular function of PINs remains unknown. Here, we show that PINs mediate auxin efflux from mammalian and yeast cells without needing additional plant-specific factors. Conditional gain-of-function alleles and quantitative measurements of auxin accumulation in Arabidopsis and tobacco cultured cells revealed that the action of PINs in auxin efflux is distinct from PGP, rate-limiting, specific to auxins, and sensitive to auxin transport inhibitors. This suggests a direct involvement of PINs in catalyzing cellular auxin efflux.