PMID- 29580375 OWN - NLM STAT- MEDLINE DCOM- 20180910 LR - 20191210 IS - 1976-670X (Electronic) IS - 1976-6696 (Print) IS - 1976-6696 (Linking) VI - 51 IP - 4 DP - 2018 Apr TI - Photoperiod sensing system for timing of flowering in plants. PG - 163-164 AB - CONSTANS (CO) induces the expression of FLOWERING LOCUS T (FT) in the photoperiodic pathway, and thereby regulates the seasonal timing of flowering. CO expression is induced and CO protein is stabilized by FLAVIN-BINDING KELCH REPEAT F-BOX PROTEIN 1 (FKF1) in the late afternoon, while CO is degraded by CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) during the night. These regulatory cascades were thought to act independently. In our study, we investigated the relationship between FKF1 and COP1 in the regulation of CO stability in response to ambient light conditions. A genetic analysis revealed that FKF1 acts as a direct upstream negative regulator of COP1, in which cop1 mutation is epistatic to fkf1 mutation in the photoperiodic regulation of flowering. COP1 activity requires the formation of a hetero-tetramer with SUPPRESSOR OF PHYA-105 (SPA1), [(COP1)2(SPA1)2]. Light-activated FKF1 has an increased binding capacity for COP1, forming a FKF1-COP1 hetero-dimer, and inhibiting COP1 homo-dimerization at its coiled-coil (CC) domain. Mutations in the CC domain result in poor COP1 dimerization and misregulation of photoperiodic floral induction. We propose that FKF1 represses COP1 activity by inhibiting COP1 dimerization in the late afternoon under long-day conditions, resulting in early flowering. [BMB Reports 2018; 51(4): 163-164]. FAU - Lee, Byoung-Doo AU - Lee BD AD - Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea. FAU - Cha, Joon-Yung AU - Cha JY AD - Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju 52828, Korea. FAU - Kim, Mi Ri AU - Kim MR AD - Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju 52828, Korea. FAU - Paek, Nam-Chon AU - Paek NC AD - Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea. FAU - Kim, Woe-Yeon AU - Kim WY AD - Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju 52828, Korea. LA - eng PT - Editorial PL - Korea (South) TA - BMB Rep JT - BMB reports JID - 101465334 RN - 0 (Arabidopsis Proteins) RN - 0 (CONSTANS protein, Arabidopsis) RN - 0 (DNA-Binding Proteins) RN - 0 (FKF1 protein, Arabidopsis) RN - 0 (Transcription Factors) RN - EC 2.3.2.27 (AT2G32950 protein, Arabidopsis) RN - EC 2.3.2.27 (Ubiquitin-Protein Ligases) SB - IM MH - Arabidopsis/metabolism MH - Arabidopsis Proteins/*genetics/*metabolism MH - Circadian Rhythm MH - DNA-Binding Proteins/genetics/metabolism MH - Gene Expression Regulation, Plant/genetics MH - Light MH - Magnoliopsida/genetics MH - Photoperiod MH - Plants, Genetically Modified/metabolism MH - Promoter Regions, Genetic/genetics MH - Transcription Factors/genetics/metabolism MH - Ubiquitin-Protein Ligases PMC - PMC5933209 EDAT- 2018/03/28 06:00 MHDA- 2018/09/11 06:00 PMCR- 2018/05/01 CRDT- 2018/03/28 06:00 PHST- 2018/03/10 00:00 [received] PHST- 2018/03/28 06:00 [pubmed] PHST- 2018/09/11 06:00 [medline] PHST- 2018/03/28 06:00 [entrez] PHST- 2018/05/01 00:00 [pmc-release] AID - 4129 [pii] AID - bmb-51-163 [pii] AID - 10.5483/bmbrep.2018.51.4.052 [doi] PST - ppublish SO - BMB Rep. 2018 Apr;51(4):163-164. doi: 10.5483/bmbrep.2018.51.4.052.