scholarly journals Dimer formation in the blue light sensing protein Vivid

2009 ◽  
Vol 96 (3) ◽  
pp. 524a ◽  
Author(s):  
Jessica S. Lamb ◽  
Brian D. Zoltowski ◽  
Suzette A. Palin ◽  
Li Li ◽  
Brian R. Crane ◽  
...  
Keyword(s):  
Blue Light ◽  
Dimer Formation ◽  
Light Sensing

scholarly journals Blue light sensing in higher plants.

2001 ◽  
Vol 276 (20) ◽  
pp. 17620
Author(s):  
John M. Christie ◽  
Winslow R. Briggs
Keyword(s):  
Blue Light ◽  
Higher Plants ◽  
Light Sensing

Blue Light Sensing and Signaling by the Phototropins

2005 ◽  
pp. 277-303 ◽  
Author(s):  
John M. Christie ◽  
Winslow R. Briggs
Keyword(s):  
Blue Light ◽  
Light Sensing

scholarly journals Red- and Blue-Light Sensing in the Plant Pathogen Alternaria alternata Depends on Phytochrome and the White-Collar Protein LreA

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Olumuyiwa Igbalajobi ◽  
Zhenzhong Yu ◽  
Reinhard Fischer
Keyword(s):  
Blue Light ◽  
Alternaria Alternata ◽  
Red Light ◽  
White Collar ◽  
Nuclear Accumulation ◽  
Model Organisms ◽  
Light Induction ◽  
Content Type ◽  
High Osmolarity ◽  
Light Sensing

ABSTRACT The filamentous fungus Alternaria alternata is a common postharvest contaminant of food and feed, and some strains are plant pathogens. Many processes in A. alternata are triggered by light. Interestingly, blue light inhibits sporulation, and red light reverses the effect, suggesting interactions between light-sensing systems. The genome encodes a phytochrome (FphA), a white collar 1 (WC-1) orthologue (LreA), an opsin (NopA), and a cryptochrome (CryA) as putative photoreceptors. Here, we investigated the role of FphA and LreA and the interplay with the high-osmolarity glycerol (HOG) mitogen-activated protein (MAP) kinase pathway. We created loss-of function mutations for fphA, lreA, and hogA using CRISPR-Cas9 technology. Sporulation was reduced in all three mutant strains already in the dark, suggesting functions of the photoreceptors FphA and LreA independent of light perception. Germination of conidia was delayed in red, blue, green, and far-red light. We found that light induction of ccgA (clock-controlled gene in Neurospora crassa and light-induced gene in Aspergillus nidulans) and the catalase gene catA depended on FphA, LreA, and HogA. Light induction of ferA (a putative ferrochelatase gene) and bliC (bli-3, light regulated, unknown function) required LreA and HogA but not FphA. Blue- and green-light stimulation of alternariol formation depended on LreA. A lack of FphA or LreA led to enhanced resistance toward oxidative stress due to the upregulation of catalases and superoxide dismutases. Light activation of FphA resulted in increased phosphorylation and nuclear accumulation of HogA. Our results show that germination, sporulation, and secondary metabolism are light regulated in A. alternata with distinct and overlapping roles of blue- and red-light photosensors. IMPORTANCE Light controls many processes in filamentous fungi. The study of light regulation in a number of model organisms revealed an unexpected complexity. Although the molecular components for light sensing appear to be widely conserved in fungal genomes, the regulatory circuits and the sensitivity of certain species toward specific wavelengths seem different. In N. crassa, most light responses are triggered by blue light, whereas in A. nidulans, red light plays a dominant role. In Alternaria alternata, both blue and red light appear to be important. In A. alternata, photoreceptors control morphogenetic pathways, the homeostasis of reactive oxygen species, and the production of secondary metabolites. On the other hand, high-osmolarity sensing required FphA and LreA, indicating a sophisticated cross talk between light and stress signaling.

scholarly journals Insights into histidine kinase activation mechanisms from the monomeric blue light sensor EL346

2019 ◽  
Vol 116 (11) ◽  
pp. 4963-4972 ◽  
Author(s):  
Igor Dikiy ◽  
Uthama R. Edupuganti ◽  
Rinat R. Abzalimov ◽  
Peter P. Borbat ◽  
Madhur Srivastava ◽  
...  
Keyword(s):  
Blue Light ◽  
Conformational Changes ◽  
Histidine Kinase ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Catalytic Domain ◽  
Response Regulator ◽  
Phosphoryl Group ◽  
Dark State ◽  
Light Sensing

Translation of environmental cues into cellular behavior is a necessary process in all forms of life. In bacteria, this process frequently involves two-component systems in which a sensor histidine kinase (HK) autophosphorylates in response to a stimulus before subsequently transferring the phosphoryl group to a response regulator that controls downstream effectors. Many details of the molecular mechanisms of HK activation are still unclear due to complications associated with the multiple signaling states of these large, multidomain proteins. To address these challenges, we combined complementary solution biophysical approaches to examine the conformational changes upon activation of a minimal, blue-light–sensing histidine kinase from Erythrobacter litoralis HTCC2594, EL346. Our data show that multiple conformations coexist in the dark state of EL346 in solution, which may explain the enzyme’s residual dark-state activity. We also observe that activation involves destabilization of the helices in the dimerization and histidine phosphotransfer-like domain, where the phosphoacceptor histidine resides, and their interactions with the catalytic domain. Similar light-induced changes occur to some extent even in constitutively active or inactive mutants, showing that light sensing can be decoupled from activation of kinase activity. These structural changes mirror those inferred by comparing X-ray crystal structures of inactive and active HK fragments, suggesting that they are at the core of conformational changes leading to HK activation. More broadly, our findings uncover surprising complexity in this simple system and allow us to outline a mechanism of the multiple steps of HK activation.

scholarly journals From Plant Infectivity to Growth Patterns: The Role of Blue-Light Sensing in the Prokaryotic World

Plants ◽  
2014 ◽  
Vol 3 (1) ◽  
pp. 70-94 ◽  
Author(s):  
Aba Losi ◽  
Carmen Mandalari ◽  
Wolfgang Gärtner
Keyword(s):  
Blue Light ◽  
Growth Patterns ◽  
Light Sensing

scholarly journals Genetic dissection of blue-light sensing in tomato using mutants deficient in cryptochrome 1 and phytochromes A, B1 and B2

2001 ◽  
Vol 25 (4) ◽  
pp. 427-440 ◽  
Author(s):  
James L. Weller ◽  
Gaetano Perrotta ◽  
Mariëlle E.L. Schreuder ◽  
Ageeth Van Tuinen ◽  
Maarten Koornneef ◽  
...  
Keyword(s):  
Blue Light ◽  
Genetic Dissection ◽  
Light Sensing ◽  
Cryptochrome 1

scholarly journals Applications of vibrational spectroscopy in the study of flavin-based photoactive proteins

2011 ◽  
Vol 25 (6) ◽  
pp. 261-269 ◽  
Author(s):  
Jiang Li ◽  
Teizo Kitagawa
Keyword(s):  
Signal Transduction ◽  
Raman Spectroscopy ◽  
Blue Light ◽  
Reaction Mechanisms ◽  
Flavin Adenine Dinucleotide ◽  
Spectroscopic Studies ◽  
Biological Functions ◽  
Light Sensing ◽  
Infrared And Raman Spectroscopy ◽  
Sensitive Tool

Flavin cofactor is known to perform diverse biological functions. Recently, its role as a photoreceptor has been identified. So far, three classes of photoactive flavoproteins have been recognized: phototropin with LOV (Light, Oxygen and Voltage) domain, blue light sensory protein with BLUF (Blue Light sensing Using Flavin adenine dinucleotide) domain and photolyase/cryptochrome protein with PHR (Photolyase Homology Region) domain. Photochemistry of flavin is the key to unravel the reaction mechanisms of photoactive flavoproteins in their biological functions such as DNA repair or signal transduction. Vibrational (Infrared and Raman) spectroscopy is a useful and sensitive tool to investigate the photochemistry of flavin in protein environments and has significantly contributed to elucidate the reaction mechanisms of these photoactive proteins. This study will survey recent advances in vibrational spectroscopic studies on this topic and remaining questions to be answered.

scholarly journals Seeing the Light: The Roles of Red- and Blue-Light Sensing in Plant Microbes

2018 ◽  
Vol 56 (1) ◽  
pp. 41-66 ◽  
Author(s):  
Gwyn A. Beattie ◽  
Bridget M. Hatfield ◽  
Haili Dong ◽  
Regina S. McGrane
Keyword(s):  
Blue Light ◽  
Molecular Mechanisms ◽  
Red Light ◽  
Light Availability ◽  
Photosynthetic Apparatus ◽  
Light Regulation ◽  
Environmental Signals ◽  
Light Sensing ◽  
Fungal Phytopathogens ◽  
Bacteria And Fungi

Plants collect, concentrate, and conduct light throughout their tissues, thus enhancing light availability to their resident microbes. This review explores the role of photosensing in the biology of plant-associated bacteria and fungi, including the molecular mechanisms of red-light sensing by phytochromes and blue-light sensing by LOV (light-oxygen-voltage) domain proteins in these microbes. Bacteriophytochromes function as major drivers of the bacterial transcriptome and mediate light-regulated suppression of virulence, motility, and conjugation in some phytopathogens and light-regulated induction of the photosynthetic apparatus in a stem-nodulating symbiont. Bacterial LOV proteins also influence light-mediated changes in both symbiotic and pathogenic phenotypes. Although red-light sensing by fungal phytopathogens is poorly understood, fungal LOV proteins contribute to blue-light regulation of traits, including asexual development and virulence. Collectively, these studies highlight that plant microbes have evolved to exploit light cues and that light sensing is often coupled with sensing other environmental signals.

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