Beyond ubiquitination: proteolytic and nonproteolytic roles of HOS1.
The E3 ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1) functions as a cold signaling attenuator by degrading the INDUCER OF CBF EXPRESSION 1 transcription factor, which is a key regulator of the cold-induced transcriptome and freezing tolerance in plants. Recent studies demonstrate that HOS1 also plays nonproteolytic roles in gene expression regulation. HOS1 acts as a chromatin remodeling factor that modulates FLOWERING LOCUS C chromatin in cold regulation of flowering time. It associates with the nuclear pore complex to facilitate nucleocytoplasmic mRNA export to maintain circadian periodicity over a range of light and temperature conditions. In this review, we summarize recent advances in molecular mechanisms underlying HOS1 function during plant development in response to fluctuating environmental conditions.
Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.
Jae-Hoon
JH
Jung
Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Hyo-Jun
HJ
Lee
Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
Mi-Jeong
MJ
Park
Department of Chemistry, Seoul National University, Seoul 151-742, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea. Electronic address: cmpark@snu.ac.kr.
Chung-Mo
CM
Park
D003080:Cold Temperature; D017440:Photoperiod; D010940:Plant Proteins / Q000378:metabolism*; D054046:Plant Stomata / Q000254:growth & development; D059748:Proteolysis; D054875:Ubiquitination
D010940:Plant Proteins
E3 ubiquitin ligase; HOS1; chromatin remodeling; circadian clock; mRNA export; photoperiodic flowering