title: ICE1 Ser403 is necessary for protein stabilization and regulation of cold signaling and tolerance.
abstract: ICE1, a MYC-type transcription factor, has an important role in the induction of CBF3/DREB1A for regulation of cold signaling and tolerance. Here we reveal that serine 403 of ICE1 is involved in regulating the transactivation and stability of the ICE1 protein. Substitution of serine 403 by alanine enhanced the transactivational activity of ICE1 in Arabidopsis protoplasts. Over-expression of ICE1(S403A) conferred more freezing tolerance than ICE1(WT) in Arabidopsis, and the expression of cold-regulated genes such as CBF3/DREB1A, COR47 and KIN1 was enhanced in plants over-expressing ICE1(S403A). Furthermore, the ICE1(S403A) protein level was not changed after cold treatment, whereas the ICE1(WT) protein level was reduced. Interestingly, polyubiquitylation of the ICE1(S403A) protein in vivo was apparently blocked. These results demonstrate that serine 403 of ICE1 has roles in both transactivation and cold-induced degradation of ICE1 via the ubiquitin/26S proteasome pathway, suggesting that serine 403 is a key residue for the attenuation of cold-stress responses by HOS1-mediated degradation of ICE1.
authors: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan. kmiura@gene.tsukuba.ac.jp
authors: Kenji
authors: K
authors: Miura
authors: Masaru
authors: M
authors: Ohta
authors: Machiko
authors: M
authors: Nakazawa
authors: Michiyuki
authors: M
authors: Ono
authors: Paul M
authors: PM
authors: Hasegawa
mesh_terms: D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D058639:Cold-Shock Response; D061269:DNA Transformation Competence; D018506:Gene Expression Regulation, Plant; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D012694:Serine / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D025801:Ubiquitin / Q000378:metabolism; D054875:Ubiquitination
chemical_list: D029681:Arabidopsis Proteins; C510502:ICE1 protein, Arabidopsis; D018749:RNA, Plant; D014157:Transcription Factors; D025801:Ubiquitin; D012694:Serine; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease