The CUL3A–LFH1–UBC15 ubiquitin ligase complex mediates SHORT VEGETATIVE PHASE degradation to accelerate flowering at high ambient temperature  

作　　者：Suhyun Jin Geummin Youn Sun Young Kim Taewook Kang Hyun-young Shin Ji-Yul Jung Pil Joon Seo Ji Hoon Ahn 

机构地区：[1]Department of Life Sciences,Korea University,Seoul 02841,Republic of Korea [2]Department of Chemistry,Seoul National University,Seoul 08826,Republic of Korea [3]These authors contributed equally to this article.

出　　处：《Plant Communications》2024年第4期224-238,共15页植物通讯（英文）

基　　金：supported by grants from the National Research Foundation of Korea (NRF-2022R1A3B1078180 and RS-2023-00221182 to J.H.A.and NRF-2022R1A2B5B02001266 to P.J.S.).

摘　　要：Ambient temperature affects flowering time in plants,and the MADS-box transcription factor SHORT VEGETATIVE PHASE(SVP)plays a crucial role in the response to changes in ambient temperature.SVP protein stability is regulated by the 26S proteasome pathway and decreases at high ambient temperature,but the details of SVP degradation are unclear.Here,we show that SVP degradation at high ambient temperature is mediated by the CULLIN3–RING E3 ubiquitin ligase(CRL3)complex in Arabidopsis thaliana.We identified a previously uncharacterized protein that interacts with SVP at high ambient temperature and contains a BTB/POZ domain.We named this protein LATE FLOWERING AT HIGH TEMPERATURE 1(LFH1).Single mutants of LFH1 or CULLIN3A(CUL3A)showed late flowering specifically at 27C.LFH1 protein levels increased at high ambient temperature.We found that LFH1 interacts with CUL3A in the cytoplasm and is important for SVP–CUL3A complex formation.Mutations in CUL3A and/or LFH1 led to increased SVP protein stability at high ambient temperature,suggesting that the CUL3–LFH1 complex functions in SVP degradation.Screening E2 ubiquitin-conjugating enzymes(UBCs)using RING-BOX PROTEIN 1(RBX1),a component of the CRL3 complex,as bait identified UBC15.ubc15 mutants also showed late flowering at high ambient temperature.In vitro and in vivo ubiquitination assays using recombinant CUL3A,LFH1,RBX1,and UBC15 showed that SVP is highly ubiquitinated in an ATP-dependent manner.Collectively,these results indicate that the degradation of SVP at high ambient temperature is mediated by a CRL3 complex comprising CUL3A,LFH1,and UBC15.

关 键 词：temperature-responsive flowering SVP CUL3 proteasomal degradation UBIQUITINATION 

分 类 号：Q94[生物学—植物学]