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A novel putative auxin carrier family regulates intracellular auxin homeostasis in plants


The phytohormone auxin acts as a prominent signal, providing, by its local accumulation or depletion in selected cells, a spatial and temporal reference for changes in the developmental program1,2,3,4,5,6,7. The distribution of auxin depends on both auxin metabolism (biosynthesis, conjugation and degradation)8,9,10 and cellular auxin transport11,12,13,14,15. We identified in silico a novel putative auxin transport facilitator family, called PIN-LIKES (PILS). Here we illustrate that PILS proteins are required for auxin-dependent regulation of plant growth by determining the cellular sensitivity to auxin. PILS proteins regulate intracellular auxin accumulation at the endoplasmic reticulum and thus auxin availability for nuclear auxin signalling. PILS activity affects the level of endogenous auxin indole-3-acetic acid (IAA), presumably via intracellular accumulation and metabolism. Our findings reveal that the transport machinery to compartmentalize auxin within the cell is of an unexpected molecular complexity and demonstrate this compartmentalization to be functionally important for a number of developmental processes.

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Figure 1: Novel PILS protein family.
Figure 2: Phenotypes of PILS loss- and gain-of function mutants.
Figure 3: PILS proteins affect auxin-dependent cellular growth.
Figure 4: PILS involvement in cellular auxin homeostasis.


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We are grateful to C. Braeckman for plant transformation; W. Ardiles for sequencing support; L. Charrier for technical assistance; A. Maizel, N. Geldner and P. Pimpl for providing material; J.K.-V. group members for critical reading of the manuscript and the BOKU-VIBT Imaging Center for access and expertise. This work was supported by the Vienna Science and Technology Fund (WWTF) (to J.K.-V.), the Agency for Innovation by Science and Technology (IWT) (predoctoral fellowship to E.B.), the Odysseus program of the Research Foundation-Flanders (to J.F.), the Swiss National Funds (to M.G.), the Ministry of Education, Youth and Sports of the Czech Republic (LC06034) (to E.Z.), Grant Agency of the Czech Republic project P305/11/2476 (to J.P.) and P305/11/0797 (to E.Z).

Author information




E.B. and J.K.V. conceived the project. E.B. carried out most of the experiments. M.K., P.I.B., E.Z. and J.P. performed auxin metabolite profile and auxin accumulation in BY-2. C.B. analysed auxin-dependent PILS expression and contributed to phenotype analysis. M.R.R. contributed to PILS cloning. J.R. and A.P. measured auxin content in Arabidopsis. B.W., J.Z. and M.G. performed auxin accumulation in yeast and protoplasts. Y.L. modified the oestradiol-inducible vector. E.B., M.K., J.R., E.Z., J.P., M.G., J.F. and J.K.V. discussed the experimental procedures. All authors analysed and discussed the data; E.B. and J.K.V. wrote the paper and all authors saw and commented on the manuscript.

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Correspondence to Jürgen Kleine-Vehn.

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The authors declare no competing financial interests.

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Barbez, E., Kubeš, M., Rolčík, J. et al. A novel putative auxin carrier family regulates intracellular auxin homeostasis in plants. Nature 485, 119–122 (2012).

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