Identification of Arabidopsis MYB56 as a novel substrate for CRL3(BPM) E3 ligases

Mol Plant. 2015 Feb;8(2):242-50. doi: 10.1016/j.molp.2014.10.004. Epub 2014 Dec 11.

Abstract

Controlled stability of proteins is a highly efficient mechanism to direct diverse processes in living cells. A key regulatory system for protein stability is given by the ubiquitin proteasome pathway, which uses E3 ligases to mark specific proteins for degradation. In this work, MYB56 is identified as a novel target of a CULLIN3 (CUL3)-based E3 ligase. Its stability depends on the presence of MATH-BTB/POZ (BPM) proteins, which function as substrate adaptors to the E3 ligase. Genetic studies have indicated that MYB56 is a negative regulator of flowering, while BPMs positively affect this developmental program. The interaction between BPMs and MYB56 occurs at the promoter of FLOWERING LOCUS T (FT), a key regulator in initiating flowering in Arabidopsis, and results in instability of MYB56. Overall the work establishes MYB transcription factors as substrates of BPM proteins, and provides novel information on components that participate in controlling flowering time in plants.

Keywords: BPM; CUL3; E3 ligase; MYB; flowering; transcription factor.

Publication types

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

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Promoter Regions, Genetic / genetics
  • Transcription Factors / metabolism*
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • Arabidopsis Proteins
  • FT protein, Arabidopsis
  • MYB56 protein, Arabidopsis
  • Transcription Factors
  • Ubiquitin-Protein Ligases