AtSNX1 defines an endosome for auxin-carrier trafficking in Arabidopsis

Nature. 2006 Sep 7;443(7107):106-9. doi: 10.1038/nature05046. Epub 2006 Aug 27.


Polarized cellular distribution of the phytohormone auxin and its carriers is essential for normal plant growth and development. Polar auxin transport is maintained by a network of auxin influx (AUX) and efflux (PIN) carriers. Both auxin transport and PIN protein cycling between the plasma membrane and endosomes require the activity of the endosomal GNOM; however, intracellular routes taken by these carriers remain largely unknown. Here we show that Arabidopsis thaliana SORTING NEXIN 1 (AtSNX1) is involved in the auxin pathway and that PIN2, but not PIN1 or AUX1, is transported through AtSNX1-containing endosomes. We demonstrate that the snx1-null mutant exhibits multiple auxin-related defects and that loss of function of AtSNX1 severely enhances the phenotype of a weak gnom mutant. In root cells, we further show that AtSNX1 localizes to an endosomal compartment distinct from GNOM-containing endosomes, and that PIN2 accumulates in this compartment after treatment with the phosphatidylinositol-3-OH kinase inhibitor wortmannin or after a gravity stimulus. Our data reveal the existence of a novel endosomal compartment involved in PIN2 endocytic sorting and plant development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androstadienes / pharmacology
  • Arabidopsis / cytology*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Endosomes / metabolism*
  • Indoleacetic Acids / metabolism*
  • Membrane Transport Proteins / metabolism
  • Mutation
  • Plant Roots / cytology
  • Plant Roots / metabolism
  • Protein Transport
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • Wortmannin


  • AUX1 protein, Arabidopsis
  • Androstadienes
  • Arabidopsis Proteins
  • Carrier Proteins
  • Indoleacetic Acids
  • Membrane Transport Proteins
  • PIN1 protein, Arabidopsis
  • PIN2 protein, Arabidopsis
  • Vesicular Transport Proteins
  • Wortmannin