Nuclear protein phosphatases with Kelch-repeat domains modulate the response to brassinosteroids in Arabidopsis

Genes Dev. 2004 Feb 15;18(4):448-60. doi: 10.1101/gad.1174204. Epub 2004 Feb 20.


Perception of the plant steroid hormone brassinolide (BL) by the membrane-associated receptor kinase BRI1 triggers the dephosphorylation and accumulation in the nucleus of the transcriptional modulators BES1 and BZR1. We identified bsu1-1D as a dominant suppressor of bri1 in A abidopsis. BSU1 encodes a nuclear-localized serine-threonine protein phosphatase with an N-terminal Kelch-repeat domain, and is preferentially expressed in elongating cells. BSU1 is able to modulate the phosphorylation state of BES1, counter acting the action of the glycogen synthase kinase-3 BIN2, and leading to inc eased steady-state levels of dephosphorylated BES1. BSU1 belongs to a small gene family; loss-of-function analyses unravel the extent of functional overlap among members of the family and confirm the role of these phosphatases in the control of cell elongation by BL. Our data indicate that BES1 is subject to antagonistic phosphorylation and dephosphorylation reactions in the nucleus, which fine-tune the amplitude of the response to BL.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / enzymology*
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Cell Nucleus / enzymology*
  • DNA-Binding Proteins
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phosphoprotein Phosphatases / chemistry*
  • Phosphoprotein Phosphatases / genetics*
  • Phosphoprotein Phosphatases / metabolism*
  • Phytosterols / pharmacology*
  • Plant Leaves / genetics
  • Promoter Regions, Genetic
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • Arabidopsis Proteins
  • BZR1 protein, Arabidopsis
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Phytosterols
  • BSU1 protein, Arabidopsis
  • Phosphoprotein Phosphatases

Associated data

  • GENBANK/AY372269