The negative regulator of plant cold responses, HOS1, is a RING E3 ligase that mediates the ubiquitination and degradation of ICE1

Plant responses to cold stress are mediated by a transcriptional cascade, in which the transcription factor ICE1 and possibly related proteins activate the expression of C-repeat (CRT)-binding factors (CBFs), leading to the transcription of downstream effector genes. The variant RING finger protein high expression of osmotically responsive gene (HOS)1 was identified genetically as a negative regulator of cold responses. We present evidence here that HOS1 is an E3 ligase required for the ubiquitination of ICE1. HOS1 physically interacts with ICE1 and mediates the ubiquitination of ICE1 both in vitro and in vivo. We found that cold induces the degradation of ICE1 in plants, and this degradation requires HOS1.…

• NS
  National Science Foundation

  Awards: 0212346, IBN-0212346, 0241450
• UD
  U.S. Department of Agriculture
• HU
  Harvard University
• NI
  National Institutes of Health

  Award: R01GM59138