<i>Arabidopsis</i> COP10 is a ubiquitin-conjugating enzyme variant that acts together with COP1 and the COP9 signalosome in repressing photomorphogenesis

Suzuki, Genki; Yanagawa, Yuki; Kwok, Shing F.; Matsui, Minami; Deng, Xing‐Wang

doi:10.1101/gad.964602

Cited by 113 publications

(137 citation statements)

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“…In darkness, COP1 interacts with and down-regulates several transcription factors that act as positive components in light signaling (Ang et al, 1998;Hardtke et al, 2000;Osterlund et al, 2000;Yamamoto et al, 1998Yamamoto et al, , 2001Seo et al, 2003). Other cop/det/fus loci encode an ubiquitin-conjugating enzyme or components of the COP9 signalosome complex, which was proposed to function in the proteasome-mediated protein degradation (Suzuki et al, 2002;Serino et al, 2003). Together, these findings led to the hypothesis that the primary mode of phytochrome signaling for seedling development involves posttranslational regulation on the nuclear transcription (Nagy and Schäfer, 2002).…”

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confidence: 95%

Overexpression of a Mutant Basic Helix-Loop-Helix Protein HFR1, HFR1-ΔN105, Activates a Branch Pathway of Light Signaling in Arabidopsis

et al. 2003

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The HFR1, a basic helix-loop-helix protein, is required for a subset of phytochrome A-mediated photoresponses in Arabidopsis. Here, we show that overexpression of the HFR1-⌬N105 mutant, which lacks the N-terminal 105 amino acids, confers exaggerated photoresponses even in darkness. Physiological analysis implied that overexpression of HFR1-⌬N105 activated constitutively a branch pathway of light signaling that mediates a subset of photomorphogenic responses, including germination, de-etiolation, gravitropic hypocotyl growth, blocking of greening, and expression of some lightregulated genes such as CAB, DRT112, PSAE, PSBL, PORA, and XTR7, without affecting the light-responsiveness of anthocyanin accumulation and expression of other light-regulated genes such as CHS and PSBS. Although the end-of-day far-red light response and petiole elongation were suppressed in the HFR1-⌬N105-overexpressing plants, flowering time was not affected by HFR1-⌬N105. In addition, the HFR1-⌬N105-overexpressing plants showed hypersensitive photoresponses in the inhibition of hypocotyl elongation, dependently on phytochrome A, FHY1, and FHY3 under FR light or phyB under R light, respectively. Moreover, our double mutant analysis suggested that the hypersensitive photoresponse is due to functional cooperation between HFR1-⌬N105 and other light-signaling components including HY5, a basic leucine zipper protein. Taken together, our results of gain-of-function approach with HFR1-⌬N105 suggest the existence of a complex and important basic helix-loop-helix protein-mediated transcriptional network controlling a branch pathway of light signaling and provide a useful framework for further genetic dissection of light-signaling network in Arabidopsis.Plants sense light not only as an energy source but also to collect information about their surrounding environments, such as seasonal changes and proximity of neighboring plants ( Kendrick and Kronenberg, 1994). Being sessile and photoautotrophs, plants have evolved sophisticated photosensory and regulatory systems to optimize their fitness in response to changing light conditions (Smith, 2000). Light affects various aspects of growth and development in higher plants throughout life cycles, from germination to flowering (Fankhauser and Chory, 1997). The early stage of seedling development clearly illustrates such light-dependent development. Seedlings grown in the dark undergo skotomorphogenesis, characterized by elongated hypocotyls and yellow, closed cotyledons. In response to light, seedlings follow the photomorphogenic developmental program; hypocotyls cease elongating, cotyledons become green and unfolded, and the seedlings become photosynthesis competent. Dramatic changes in gene expression underlie these marked developmental changes. Multiple genes encoding transcription factors are up-or down-regulated by light within 1 h after irradiation (Tepperman et al., 2001). Such changes in transcription factors are presumed to regulate the orchestrated expression of various downstream light-regulated...

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confidence: 95%

Overexpression of a Mutant Basic Helix-Loop-Helix Protein HFR1, HFR1-ΔN105, Activates a Branch Pathway of Light Signaling in Arabidopsis

et al. 2003

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“…Some of the mutants and transgenic lines used in this study were described previously: spa1-3 (Hoecker et al, 1998), spa2-1, spa1 spa2, spa1 spa2 spa3, spa1 spa2 spa4, and spa1 spa3 spa4 (Laubinger et al, 2004), spa3-1, spa4-1, andspa3 spa4 (Laubinger and, spa2 spa3 spa4 (Fittinghoff et al, 2006), cop1-4, cop1-5, andcop1-6 (McNellis et al, 1994), cop9-1 (Wei and Deng, 1992), det1-1 (Chory et al, 1989), cop10-1 (Suzuki et al, 2002), 35S:TAP-SPA1 (Saijo et al, 2003), 35S:myc-SPA1 (Yang and Wang, 2006), and 35S:TAP-COP1 (Rubio et al, 2005).…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

Biochemical Characterization ofArabidopsisComplexes Containing CONSTITUTIVELY PHOTOMORPHOGENIC1 and SUPPRESSOR OF PHYA Proteins in Light Control of Plant Development

et al. 2008

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COP1 (for CONSTITUTIVELY PHOTOMORPHOGENIC1) and the four partially redundant SPA (for SUPPRESSOR OF PHYA) proteins work in concert to repress photomorphogenesis in Arabidopsis thaliana by targeting key transcription factors and phytochrome A for degradation via the 26S proteasome. Here, we report a detailed biochemical characterization of the SPA-COP1 complexes. The four endogenous SPA proteins can form stable complexes with COP1 in vivo regardless of light conditions but exhibit distinct expression profiles in different tissues and light conditions. The SPA proteins can self-associate or interact with each other, forming a heterogeneous group of SPA-COP1 complexes in which the exact SPA protein compositions vary depending on the abundance of individual SPA proteins. The four SPA proteins could be divided into two functional groups depending on their interaction affinities, their regulation of ELONGATED HYPOCOTYL5 degradation, and their opposite effects on COP1 protein accumulation. Loss-of-function mutations in a predominant SPA protein may cause a significant reduction in the overall SPA-COP1 E3 ligase activity, resulting in a partial constitutive photomorphogenic phenotype. This study thus provides an in-depth biochemical view of the SPA-COP1 E3 ligase complexes and offers new insights into the molecular basis for their distinct roles in the light control of plant development.

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“…through the help of COP1 and CSN (Hellmann and Estelle, 2002;Suzuki et al, 2002). COP10 may also be involved in HY5 degradation (Suzuki et al, 2002). Together these results implicate that light signaling and ubiquitin-mediated pathways are interconnected in a larger dimension than earlier anticipated.…”

Section: Ubiquitin-mediated Protein Degradation and Phytochrome Signamentioning

confidence: 39%

“…As a result, LAF1 and HY5 bind to the light responsive elements (LREs) in the promoters of lightresponsive genes and enhance their expression, leading eventually to photomorphogenesis. through the help of COP1 and CSN (Hellmann and Estelle, 2002;Suzuki et al, 2002). COP10 may also be involved in HY5 degradation (Suzuki et al, 2002).…”

Section: Ubiquitin-mediated Protein Degradation and Phytochrome Signamentioning

confidence: 99%

Phytochrome-mediated light signaling in plants: emerging trends

Paul

Khurana

2008

Physiol Mol Biol Plants

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Arabidopsis COP10 is a ubiquitin-conjugating enzyme variant that acts together with COP1 and the COP9 signalosome in repressing photomorphogenesis

Cited by 113 publications

References 33 publications

Overexpression of a Mutant Basic Helix-Loop-Helix Protein HFR1, HFR1-ΔN105, Activates a Branch Pathway of Light Signaling in Arabidopsis

Overexpression of a Mutant Basic Helix-Loop-Helix Protein HFR1, HFR1-ΔN105, Activates a Branch Pathway of Light Signaling in Arabidopsis

Biochemical Characterization ofArabidopsisComplexes Containing CONSTITUTIVELY PHOTOMORPHOGENIC1 and SUPPRESSOR OF PHYA Proteins in Light Control of Plant Development

Phytochrome-mediated light signaling in plants: emerging trends

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