Lab TabsOur ResearchThe directional response of seedlings toward a light source (phototropism) is essential for the rapid orientation of recently germinated seedlings to maximize light capture for photosynthesis as early as possible following germination. Over a decade ago the Briggs lab discovered and first characterized the photoreceptor family that mediates this directional response and named the two members phototropin 1 and phototropin 2. The Briggs group also identified the light-absorbing chromophore as flavin mononucleotide (FMN). A year later they identified the two very similar protein domains that bind the FMN (110-amino-acid domains that they designated LOV domains as they were similar to domains in a wide range of otherwise entirely different signaling proteins responding to Light, Oxygen, or Voltage.) Another year later they first described the unique photochemistry that LOV domains undergo on photoexcitation: they form a carbon-sulfur covalent bond between a carbon of the flavins and the sulfur from a nearby cysteine. This causes a change in the protein confirmation leading to autophosphorylation and consequent activation of the photoreceptor. Over a matter of seconds or minutes in darkness, the protein returns to its inactive state, prepared for another photoexcitation. Since then the laboratory has done a great deal of biochemical and biophysical work characterizing the light reaction and from this work and that of others, we now know a great deal about it. We know only a little about its deactivation that occurs in darkness. However, we recently identified the phosphatase system that interacts with one of the phototropins to remove the phosphate, an important component in the deactivation. It is now known that the phototropins mediate several other responses—leaf expansion, leaf orientation to light, chloroplast movement, stomatal opening, and rapid inhibition of hypocotyl grown in dark-grown seedlings. All of these responses relate to maximizing photosynthetic potential. Two other LOV-domain proteins, combining a single LOV domain with a downstream F-Box have been demonstrated to serve as photoreceptors involved in flowering responses to daylength and light perception in circadian rhythms. The group is also interested in the interactions of phototropins with other plant photoreceptors, for example the phytochromes. The group recently showed that phytochrome A, excited by red light, could block blue-light-induced movement of phot1 away from the plasma membrane, an inhibition that likely sensitizes the plant to the blue light stimulus. This unique interaction is currently under investigation. A variety of proteins harboring LOV domains are found in bacteria. Many of these are LOV domains upstream from histidine kinases, classic bacterial sensor proteins. In collaboration with others, the Briggs lab demonstrated that a LOV-histidine kinase in the animal pathogen Brucella was essential for virulence in an in vitro assay. However, virulence plummeted to 10 % of that expected in the light when the cultures were kept in the dark. These studies form the basis for an entirely new field of bacterial photophysiology involving determining the role of LOV-domain-based photosensors. The laboratory will be working with several of these (in non-pathogenic bacteria) in addition to working on the signal transduction pathways from the phortotropins. News Feb 12 2019 Winslow Briggs, who discovered how plant seedlings grow toward light, dies at 90 By Carnegie HQ Washington, DC— Carnegie’s Winslow Briggs, a giant in the field of plant biology who explained how seedlings grow toward light, died on February 11 at Stanford University Medical Center. He was 90. Briggs joined Carnegie as the Director of the ... Lab PI Winslow Briggs Director Emeritis Plant BiologyCarnegie Institution for Science email@example.com 650-739-4207 Office: 260 Panama StreetStanford, CA 94305, US  ProfileAffiliationCarnegie Affiliation: DPB CollaboratorsDPB Affiliation: DPB FacultyLabs: Briggs Lab Calendar Lab Members Rajnish Khanna (Outreach Coordinator)Rajnish Khanna, Ph.D. Strategic biotechnology researcher with demonstrated focus on applying multidisciplinary approaches for research and technology transfer. Innovator with a talent for solving complex problems within the agricultural industry to improve commercial crop performance for economic and health benefits. Known for empowering the industry through strategic partnerships and leveraging advanced technologies to increase product impact, governmental de-regulatory process and marketing support. Tong-seung Tseng (Research Associate) PublicationsRecent publications: Moni A, Lee AY, Briggs WR, Han IS. (2015) The blue light receptor Phototropin 1 suppresses lateral root growth by controlling cell elongation. Plant Biol (Stuttg). 1:34-40. Sycz G, Carrica MC, Tseng TS, Bogomolni RA, Briggs WR, Goldbaum FA, Paris G. (2015) LOV Histidine Kinase Modulates the General Stress Response System and Affects the virB Operon Expression in Brucella. PLoS One 5:e0124058. Briggs WR. (2014) Phototropism: some history, some puzzles, and a look ahead. Plant Physiol. 1:13-23. Deng Z, Oses-Prieto JA, Kutschera U, Tseng TS, Hao L, Burlingame AL, Wang ZY, Briggs WR (2014) Blue light-induced proteomic changes in etiolated Arabidopsis seedlings. J Proteome Res. 5:2524-33. Khanna R, Li J, Tseng TS, Schroeder JI, Ehrhardt DW, Briggs WR. (2014) COP1 jointly modulates cytoskeletal processes and electrophysiological responses required for stomatal closure. Mol Plant 9:1441-54. Han IS, Cho HY, Moni A, Lee AY, Briggs WR. (2013) Investigations on the photoregulation of chloroplast movement and leaf positioning in Arabidopsis. Plant Cell Physiol. 1:48-56. Kutschera U, Briggs WR. (2013) Seedling development in buckwheat and the discovery of the photomorphogenic shade-avoidance response. Plant Biol (Stuttg) 6:931-40. Stanga JP, Smith SM, Briggs WR, Nelson DC. (2013) SUPPRESSOR OF MORE AXILLARY GROWTH2 1 controls seed germination and seedling development in Arabidopsis. Plant Physiol. 1:318-30. Briggs WR, Lin CT. (2012) Photomorphogenesis--from one photoreceptor to 14: 40 years of progress. Mol Plant. 3:531-2. Eisinger WR, Kirik V, Lewis C, Ehrhardt DW, Briggs WR. (2012) Quantitative changes in microtubule distribution correlate with guard cell function in Arabidopsis. Mol Plant. 3:716-25. Kutschera U, Briggs WR. (2012) Root phototropism: from dogma to the mechanism of blue light perception.Planta. 3:443-52. Tseng TS, Whippo C, Hangarter RP, Briggs WR. (2012) The role of a 14-3-3 protein in stomatal opening mediated by PHOT2 in Arabidopsis. Plant Cell. 3:1114-26. Gleick PH, Adams RM, Amasino RM, Anders E, Anderson DJ, Anderson WW, Anselin LE, Arroyo MK, Asfaw B, Ayala FJ, Bax A, Bebbington AJ, Bell G, Bennett MV, Bennetzen JL, Berenbaum MR, Berlin OB, Bjorkman PJ, Blackburn E, Blamont JE, Botchan MR, Boyer JS, Boyle EA, Branton D, Briggs SP, Briggs WR, Brill WJ, Britten RJ, Broecker WS, Brown JH, Brown PO, Brunger AT, Cairns J Jr, Canfield DE, Carpenter SR, Carrington JC, Cashmore AR, Castilla JC, Cazenave A, Chapin FS 3rd, Ciechanover AJ, Clapham DE, Clark WC, Clayton RN, Coe MD, Conwell EM, Cowling EB, Cowling RM, Cox CS, Croteau RB, Crothers DM, Crutzen PJ, Daily GC, Dalrymple GB, Dangl JL, Darst SA, Davies DR, Davis MB, De Camilli PV, Dean C, DeFries RS, Deisenhofer J, Delmer DP, DeLong EF, DeRosier DJ, Diener TO, Dirzo R, Dixon JE, Donoghue MJ, Doolittle RF, Dunne T, Ehrlich PR, Eisenstadt SN, Eisner T, Emanuel KA, Englander SW, Ernst WG, Falkowski PG, Feher G, Ferejohn JA, Fersht A, Fischer EH, Fischer R, Flannery KV, Frank J, Frey PA, Fridovich I, Frieden C, Futuyma DJ, Gardner WR, Garrett CJ, Gilbert W, Goldberg RB, Goodenough WH, Goodman CS, Goodman M, Greengard P, Hake S, Hammel G, Hanson S, Harrison SC, Hart SR, Hartl DL, Haselkorn R, Hawkes K, Hayes JM, Hille B, Hökfelt T, House JS, Hout M, Hunten DM, Izquierdo IA, Jagendorf AT, Janzen DH, Jeanloz R, Jencks CS, Jury WA, Kaback HR, Kailath T, Kay P, Kay SA, Kennedy D, Kerr A, Kessler RC, Khush GS, Kieffer SW, Kirch PV, Kirk K, Kivelson MG, Klinman JP, Klug A, Knopoff L, Kornberg H, Kutzbach JE, Lagarias JC, Lambeck K, Landy A, Langmuir CH, Larkins BA, Le Pichon XT, Lenski RE, Leopold EB, Levin SA, Levitt M, Likens GE, Lippincott-Schwartz J, Lorand L, Lovejoy CO, Lynch M, Mabogunje AL, Malone TF, Manabe S, Marcus J, Massey DS, McWilliams JC, Medina E, Melosh HJ, Meltzer DJ, Michener CD, Miles EL, Mooney HA, Moore PB, Morel FM, Mosley-Thompson ES, Moss B, Munk WH, Myers N, Nair GB, Nathans J, Nester EW, Nicoll RA, Novick RP, O'Connell JF, Olsen PE, Opdyke ND, Oster GF, Ostrom E, Pace NR, Paine RT, Palmiter RD, Pedlosky J, Petsko GA, Pettengill GH, Philander SG, Piperno DR, Pollard TD, Price PB Jr, Reichard PA, Reskin BF, Ricklefs RE, Rivest RL, Roberts JD, Romney AK, Rossmann MG, Russell DW, Rutter WJ, Sabloff JA, Sagdeev RZ, Sahlins MD, Salmond A, Sanes JR, Schekman R, Schellnhuber J, Schindler DW, Schmitt J, Schneider SH, Schramm VL, Sederoff RR, Shatz CJ, Sherman F, Sidman RL, Sieh K, Simons EL, Singer BH, Singer MF, Skyrms B, Sleep NH, Smith BD, Snyder SH, Sokal RR, Spencer CS, Steitz TA, Strier KB, Südhof TC, Taylor SS, Terborgh J, Thomas DH, Thompson LG, Tjian RT, Turner MG, Uyeda S, Valentine JW, Valentine JS, Van Etten JL, van Holde KE, Vaughan M, Verba S, von Hippel PH, Wake DB, Walker A, Walker JE, Watson EB, Watson PJ, Weigel D, Wessler SR, West-Eberhard MJ, White TD, Wilson WJ, Wolfenden RV, Wood JA, Woodwell GM, Wright HE Jr, Wu C, Wunsch C, Zoback ML. (2010) Climate change and the integrity of science. Science. 7;328(5979):689-90. Erratum in: Science. 328(5980):826. Briggs, W. R. 2010. A wandering pathway from Minnesota wildflowers to phototropins to bacterial virulence. Annu. Rev. Plant Biol. 61, 1-20. Tseng, T.-S., M. A. Frederickson, W. R. Briggs, and R. A. Bogomolni. 2010. Methods in Enzymology 471. Academic Press, New York Tseng TS, Briggs WR. (2010) The Arabidopsis rcn1-1 mutation impairs dephosphorylation of Phot2, resulting in enhanced blue light responses. Plant Cell. 2:392-402., pp.125-134. Kutschera, U. and W. R. Briggs. (2009) From Charles Darwin’s botanical country-house studies to modern plant biology. Plant Biol. 11: 785-795. Tong, H., C. D. Leasure, X. Hou, G. Yuen, W. R. Briggs, Z.-H. He (2008). Role of root UV-B sensing in Arabidopsis early seedling development. Proc. Natl. Acad. Sci. U. S. A. 106: 21039-21044. Han, I.-S, W. Eisinger, T.-S. Tseng, and W. R. Briggs, 2008. Phytochrome A regulates the intracellular distribution of phototropin1-green fluorescent protein in Arabidopsis thaliana. Plant Cell 20: 2835-2847. Wan, Y-L., W. Eisinger, D. Ehrhardt, F. Baluska, and W. Briggs. 2008. The subcellular localization and blue light-induced movement of phototropin1-GFP in etiolated seedlings of Arabidopsis thaliana. Mol. Plant 1: online Nov. 2, 2007; Mol. Plant 1: 103-117. Swartz, T. E., T.-S. Tseng, M. A. Frederickson, G. Paris, D. J. Comerci, G. Rajeshekara, J.-G. Kim, M. B. Mudgett, G. Splitter, R. A. Ugalde, F. Goldbaum, W. R. Briggs, and R. A. Bogomolni. 2007. Blue light-activated histidine kinases: two-component sensors in bacteria. Science, 317: 1090-1093.