Sortin1-hypersensitive mutants link vacuolar-trafficking defects and flavonoid metabolism in Arabidopsis vegetative tissues

  • Chem Biol. 2011 Feb 25;18(2):187-97. doi: 10.1016/j.chembiol.2010.11.015.
Abel Rosado  1 ,  Glenn R Hicks ,  Lorena Norambuena ,  Ilana Rogachev ,  Sagit Meir ,  Lucille Pourcel ,  Jan Zouhar ,  Michelle Q Brown ,  Marietta P Boirsdore ,  Rachel S Puckrin ,  Sean R Cutler ,  Enrique Rojo ,  Asaph Aharoni ,  Natasha V Raikhel
Affiliations
  • 1. Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California-Riverside, CA 92521, USA.
PMID: 21338917 DOI: 10.1016/j.chembiol.2010.11.015
Abstract

Sortin1 is a chemical genetic-hit molecule that causes specific mislocalization of plant and yeast-soluble and membrane vacuolar markers. To better understand its mode of action, we designed a Sortin1-hypersensitive screen and identified several Sortin1-hypersensitive and flavonoid-defective mutants. Mechanistically, Sortin1 mimics the effect of the glutathione inhibitor buthionine sulfoximine and alters the vacuolar accumulation of Flavonoids, likely blocking their transport through vacuole-localized ABC transporters. Structure-activity relationship studies conducted in Arabidopsis revealed the structural requirements for Sortin1 bioactivity and demonstrated that overlapping Sortin1 substructures can be used to discriminate between vacuolar-flavonoid accumulations and vacuolar-biogenesis defects. We conclude that Sortin1 is a valuable probe for dissecting novel links among flavonoid transport, vacuolar integrity, and the trafficking of vacuolar targeted cargoes in Arabidopsis.

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