Dataset Information

Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs.

ABSTRACT: Plants sense different parts of the sun's light spectrum using distinct photoreceptors, which signal through the E3 ubiquitin ligase COP1. Here, we analyze why many COP1-interacting transcription factors and photoreceptors harbor sequence-divergent Val-Pro (VP) motifs that bind COP1 with different binding affinities. Crystal structures of the VP motifs of the UV-B photoreceptor UVR8 and the transcription factor HY5 in complex with COP1, quantitative binding assays, and reverse genetic experiments together suggest that UVR8 and HY5 compete for COP1. Photoactivation of UVR8 leads to high-affinity cooperative binding of its VP motif and its photosensing core to COP1, preventing COP1 binding to its substrate HY5. UVR8-VP motif chimeras suggest that UV-B signaling specificity resides in the UVR8 photoreceptor core. Different COP1-VP peptide motif complexes highlight sequence fingerprints required for COP1 targeting. The blue-light photoreceptors CRY1 and CRY2 also compete with transcription factors for COP1 binding using similar VP motifs. Thus, our work reveals that different photoreceptors and their signaling components compete for COP1 via a conserved mechanism to control different light signaling cascades.

SUBMITTER: Lau K

PROVIDER: S-EPMC6745501 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs.

Lau Kelvin K Podolec Roman R Chappuis Richard R Ulm Roman R Hothorn Michael M

The EMBO journal 20190715 18

Plants sense different parts of the sun's light spectrum using distinct photoreceptors, which signal through the E3 ubiquitin ligase COP1. Here, we analyze why many COP1-interacting transcription factors and photoreceptors harbor sequence-divergent Val-Pro (VP) motifs that bind COP1 with different binding affinities. Crystal structures of the VP motifs of the UV-B photoreceptor UVR8 and the transcription factor HY5 in complex with COP1, quantitative binding assays, and reverse genetic experiment ...[more]

PMID: 31304983

Similar Datasets

Project description:Small increases in temperature result in enhanced elongation of the hypocotyl and petioles and hyponastic growth, in an adaptive response directed to the cooling of the leaves and to protect the shoot meristem from the warm soil. This response, collectively termed as thermomorphogenesis, relies on the faster reversion of phyB Pfr at warmer temperatures, which leads to enhanced activity of the basic-helix-loop-helix PHYTOCHROME INTERACTING FACTOR 4 (PIF4). PIF4 acts as a molecular hub integrating light and temperature cues with endogenous hormonal signaling, and drives thermoresponsive growth by directly activating auxin synthesis and signaling genes. Growth promotion by PIF4 depends on brassinosteroid (BR) signaling, as indicated by the impaired thermoresponse of BR-defective mutants and the partial restoration of pifq thermoresponsive defects by brassinolide (BL) application. Also, phyB limits thermomorphogenic elongation through negative regulation of the E3 ubiquitin ligase COP1 that triggers nuclear degradation of multiple photomorphogenesis-promoting factors acting antagonistically to PIF4. COP1 is indeed observed to accumulate in the nucleus in darkness, or in response to warm temperatures, with constitutive photomorphogenic cop1 mutants failing to respond to temperature. Here we explored the role of BR signaling on COP1 function, by growing cop1 seedlings on BL or the inhibitor brassinazole (BRZ), under different light and temperature regimes. We show that weak cop1 alleles exhibit a hyposensitive response to BL. Furthermore, while cop1-6 mutants display as described a wild-type response to temperature in continuous darkness, this response is abolished by BRZ. Application of this inhibitor likewise suppressed temperature-induced COP1 nuclear accumulation in N. benthamiana leaves. Overall these results demonstrate that cop1-6 is not a temperature-conditional allele, but this mutation allows for a partially active protein which unveils a pivotal role of active BR signaling in the control of COP1 activity.

Project description:UnlabelledHigh levels of the universal bacterial second messenger cyclic di-GMP (c-di-GMP) promote the establishment of surface-attached growth in many bacteria. Not only can c-di-GMP bind to nucleic acids and directly control gene expression, but it also binds to a diverse array of proteins of specialized functions and orchestrates their activity. Since its development in the early 1990s, the synthetic peptide array technique has become a powerful tool for high-throughput approaches and was successfully applied to investigate the binding specificity of protein-ligand interactions. In this study, we used peptide arrays to uncover the c-di-GMP binding site of a Pseudomonas aeruginosa protein (PA3740) that was isolated in a chemical proteomics approach. PA3740 was shown to bind c-di-GMP with a high affinity, and peptide arrays uncovered LKKALKKQTNLR to be a putative c-di-GMP binding motif. Most interestingly, different from the previously identified c-di-GMP binding motif of the PilZ domain (RXXXR) or the I site of diguanylate cyclases (RXXD), two leucine residues and a glutamine residue and not the charged amino acids provided the key residues of the binding sequence. Those three amino acids are highly conserved across PA3740 homologs, and their singular exchange to alanine reduced c-di-GMP binding within the full-length protein.ImportanceIn many bacterial pathogens the universal bacterial second messenger c-di-GMP governs the switch from the planktonic, motile mode of growth to the sessile, biofilm mode of growth. Bacteria adapt their intracellular c-di-GMP levels to a variety of environmental challenges. Several classes of c-di-GMP binding proteins have been structurally characterized, and diverse c-di-GMP binding domains have been identified. Nevertheless, for several c-di-GMP receptors, the binding motif remains to be determined. Here we show that the use of a synthetic peptide array allowed the identification of a c-di-GMP binding motif of a putative c-di-GMP receptor protein in the opportunistic pathogen P. aeruginosa. The application of synthetic peptide arrays will facilitate the search for additional c-di-GMP receptor proteins and aid in the characterization of c-di-GMP binding motifs.

Dataset Information

Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs.

Publications

Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets