MODULATOR OF PIN genes control steady-state levels of Arabidopsis PIN proteins

Plant J. 2007 Aug;51(4):537-50. doi: 10.1111/j.1365-313X.2007.03158.x. Epub 2007 Jul 25.


Polar transport of the phytohormone auxin controls numerous growth responses in plants. Molecular characterization of auxin transport in Arabidopsis thaliana has provided important insights into the mechanisms underlying the regulation of auxin distribution. In particular, the control of subcellular localization and expression of PIN-type auxin efflux components appears to be fundamental for orchestrated distribution of the growth regulator throughout the entire plant body. Here we describe the identification of two Arabidopsis loci, MOP2 and MOP3 (for MODULATOR OF PIN), that are involved in control of the steady-state levels of PIN protein. Mutations in both loci result in defects in auxin distribution and polar auxin transport, and cause phenotypes consistent with a reduction of PIN protein levels. Genetic interaction between PIN2 and both MOP loci is suggestive of functional cross-talk, which is further substantiated by findings demonstrating that ectopic PIN up-regulation is compensated in the mop background. Thus, in addition to pathways that control PIN localization and transcription, MOP2 and MOP3 appear to be involved in fine-tuning of auxin distribution via post-transcriptional regulation of PIN expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biological Transport
  • Blotting, Northern
  • Gene Expression Regulation, Plant
  • Genes, Plant / genetics*
  • Immunohistochemistry
  • Indoleacetic Acids / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism*
  • Mutation
  • Plant Roots / genetics
  • Plant Roots / growth & development
  • Plant Roots / metabolism
  • Plant Shoots / genetics
  • Plant Shoots / growth & development
  • Plant Shoots / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism


  • Arabidopsis Proteins
  • Indoleacetic Acids
  • Membrane Transport Proteins
  • PIN1 protein, Arabidopsis
  • Recombinant Fusion Proteins