Plant UVR8 Photoreceptor Senses UV-B by Tryptophan-Mediated Disruption of Cross-Dimer Salt Bridges

Christie, John M.; Arvai, A.S.; Baxter, Katherine J.; Heilmann, Monika; Pratt, Ashley J.; O’Hara, Andrew; Kelly, Sharon M.; Hothorn, Michael; Smith, Brian O.; Hitomi, Katsundo; Jenkins, Gareth I.; Getzoff, Elizabeth D.

doi:10.1126/science.1218091

Cited by 412 publications

(640 citation statements)

References 34 publications

Supporting

Mentioning

617

Contrasting

Order By: Relevance

“…This is despite the fact that the band migrates at a lower apparent molecular mass than is expected for the denatured Cr-UVR8 homodimer. Such band patterns have been previously extensively described, including for highly purified recombinant homodimeric At-UVR8 (Rizzini et al, 2011;Christie et al, 2012;Heilmann and Jenkins, 2013). Thus, there is substantial evidence that Cr-UVR8, like At-UVR8, is homodimeric in the absence of UV-B.…”

Section: Discussion the Uvr8-cop1 Uv-b Perception And Signaling Pathwmentioning

confidence: 83%

“…The plant photoreceptor UV RESISTANCE LOCUS8 (UVR8) specifically perceives UV-B via an intrinsic tryptophan-based mechanism, mainly involving Trp-285 and Trp-233 (Rizzini et al, 2011;Christie et al, 2012;Wu et al, 2012). UVR8 is a seven-bladed b-propeller protein that exists as a homodimer maintained by interactions of charged amino acids across the dimer interaction surface (Rizzini et al, 2011;Christie et al, 2012;Wu et al, 2012;Zeng et al, 2015). The charged amino acids that maintain the homodimer are adjacent to the tryptophans involved in photoreception, suggesting that excitation of these tryptophans by UV-B neutralizes dimer-maintaining interactions Wu et al, 2012;Mathes et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

UV-B Perception and Acclimation in Chlamydomonas reinhardtii

et al. 2016

View full text Add to dashboard Cite

Plants perceive UV-B, an intrinsic component of sunlight, via a signaling pathway that is mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8) and induces UV-B acclimation. To test whether similar UV-B perception mechanisms exist in the evolutionarily distant green alga Chlamydomonas reinhardtii, we identified Chlamydomonas orthologs of UVR8 and the key signaling factor CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). Cr-UVR8 shares sequence and structural similarity to Arabidopsis thaliana UVR8, has conserved tryptophan residues for UV-B photoreception, monomerizes upon UV-B exposure, and interacts with Cr-COP1 in a UV-B-dependent manner. Moreover, Cr-UVR8 can interact with At-COP1 and complement the Arabidopsis uvr8 mutant, demonstrating that it is a functional UV-B photoreceptor. Chlamydomonas shows apparent UV-B acclimation in colony survival and photosynthetic efficiency assays. UV-B exposure, at low levels that induce acclimation, led to broad changes in the Chlamydomonas transcriptome, including in genes related to photosynthesis. Impaired UV-B-induced activation in the Cr-COP1 mutant hit1 indicates that UVR8-COP1 signaling induces transcriptome changes in response to UV-B. Also, hit1 mutants are impaired in UV-B acclimation. Chlamydomonas UV-B acclimation preserved the photosystem II core proteins D1 and D2 under UV-B stress, which mitigated UV-B-induced photoinhibition. These findings highlight the early evolution of UVR8 photoreceptor signaling in the green lineage to induce UV-B acclimation and protection.

show abstract

Section: Discussion the Uvr8-cop1 Uv-b Perception And Signaling Pathwmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

UV-B Perception and Acclimation in Chlamydomonas reinhardtii

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The W77F and W328F data, together with the unusually strict dependence of LITE-1 photoabsorption on its protein conformation, raises the intriguing possibility that LITE-1 may not have a prosthetic chromophore. Interestingly, the plant-specific protein UVR8, a soluble protein which is completely unrelated to LITE-1, also requires tryptophan residues for UVB light detection and lacks a prosthetic chromophore (Christie et al, 2012;Rizzini et al, 2011;Wu et al, 2012). This prompted us to speculate that the two tryptophan residues W77 and W328 may contribute to the formation of the chromophore of LITE-1, which may underlie its high photon-capturing efficiency.…”

Section: Discussionmentioning

confidence: 99%

The C. elegans Taste Receptor Homolog LITE-1 Is a Photoreceptor

Gong¹,

Yuan²,

Ward³

et al. 2017

Cell

View full text Add to dashboard Cite

SummaryMany animal tissues/cells are photosensitive, yet only two types of photoreceptors (opsins and cryptochromes) have been discovered in metazoans. The question arises as to whether unknown types of photoreceptors exist in the animal kingdom. LITE-1, a seven-transmembrane gustatory receptor (GR) homolog, mediates UV light-induced avoidance behavior in C. elegans. However, whether LITE-1 functions as a chemoreceptor or photoreceptor has not been determined. Here, we show that LITE-1 directly absorbs both UVA and UVB light with an extinction coefficient 10-100 times that of opsins and cryptochromes, indicating that LITE-1 is highly efficient in capturing photons. Unlike typical photoreceptor proteins employing a prosthetic chromophore to capture photons, LITE-1 strictly depends on its protein conformation for photon absorption. We further identified two tryptophan residues critical for LITE-1 function. Interestingly, unlike GPCRs, LITE-1 adopts a reversed membrane topology. Thus, LITE-1, a taste receptor homolog, represents a distinct type of photoreceptor in the animal kingdom.

show abstract

“…UVR8 exists as a homodimer in plants and rapidly monomerizes in response to UV-B (Rizzini et al, 2011;Christie et al, 2012;Wu et al, 2012). Photoactivated UVR8 then interacts with the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) (Favory et al, 2009;Rizzini et al, 2011;Cloix et al, 2012;Huang et al, 2014), which is a well-known repressor of photomorphogenesis and also plays an important role in UV-B signaling (Oravecz et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

et al. 2014

View full text Add to dashboard Cite

In plants subjected to UV-B radiation, responses are activated that minimize damage caused by UV-B. The bZIP transcription factor ELONGATED HYPOCOTYL5 (HY5) acts downstream of the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) and promotes UV-B-induced photomorphogenesis and acclimation. Expression of HY5 is induced by UV-B; however, the transcription factor(s) that regulate HY5 transcription in response to UV-B and the impact of UV-B on the association of HY5 with its target promoters are currently unclear. Here, we show that HY5 binding to the promoters of UV-B-responsive genes is enhanced by UV-B in a UVR8-dependent manner in Arabidopsis thaliana. In agreement, overexpression of REPRESSOR OF UV-B PHOTOMORPHOGENESIS2, a negative regulator of UVR8 function, blocks UV-B-responsive HY5 enrichment at target promoters. Moreover, we have identified a T/G-box in the HY5 promoter that is required for its UV-B responsiveness. We show that HY5 and its homolog HYH bind to the T/G HY5 -box cis-acting element and that they act redundantly in the induction of HY5 expression upon UV-B exposure. Therefore, HY5 is enriched at target promoters in response to UV-B in a UVR8 photoreceptor-dependent manner, and HY5 and HYH interact directly with a T/G-box cis-acting element of the HY5 promoter, mediating the transcriptional activation of HY5 in response to UV-B.

show abstract

Plant UVR8 Photoreceptor Senses UV-B by Tryptophan-Mediated Disruption of Cross-Dimer Salt Bridges

Cited by 412 publications

References 34 publications

UV-B Perception and Acclimation in Chlamydomonas reinhardtii

UV-B Perception and Acclimation in Chlamydomonas reinhardtii

The C. elegans Taste Receptor Homolog LITE-1 Is a Photoreceptor

UV-B-Responsive Association of the Arabidopsis bZIP Transcription Factor ELONGATED HYPOCOTYL5 with Target Genes, Including Its Own Promoter

Contact Info

Product

Resources

About