Journal ArticleDOI
Disruption of the LOV-Jα helix interaction activates phototropin kinase activity
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TLDR
Results indicate that unfolding of the Jalpha helix is the critical event in regulation of kinase signaling for the phototropin proteins.Abstract:
Light plays a crucial role in activating phototropins, a class of plant photoreceptors that are sensitive to blue and UV-A wavelengths. Previous studies indicated that phototropin uses a bound flavin mononucleotide (FMN) within its light-oxygen-voltage (LOV) domain to generate a protein-flavin covalent bond under illumination. In the C-terminal LOV2 domain of Avena sativa phototropin 1, formation of this bond triggers a conformational change that results in unfolding of a helix external to this domain called Jalpha [Harper, S. M., et al. (2003) Science 301, 1541-1545]. Though the structural effects of illumination were characterized, it was unknown how these changes are coupled to kinase activation. To examine this, we made a series of point mutations along the Jalpha helix to disrupt its interaction with the LOV domain in a manner analogous to light activation. Using NMR spectroscopy and limited proteolysis, we demonstrate that several of these mutations displace the Jalpha helix from the LOV domain independently of illumination. When placed into the full-length phototropin protein, these point mutations display constitutive kinase activation, without illumination of the sample. These results indicate that unfolding of the Jalpha helix is the critical event in regulation of kinase signaling for the phototropin proteins.read more
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Journal ArticleDOI
A genetically encoded photoactivatable Rac controls the motility of living cells
Yi I. Wu,Daniel Frey,Oana I. Lungu,Angelika Jaehrig,Ilme Schlichting,Brian Kuhlman,Klaus M. Hahn +6 more
TL;DR: A new approach to produce genetically encoded photoactivatable derivatives of Rac1, a key GTPase regulating actin cytoskeletal dynamics in metazoan cells, which was shown to inhibit RhoA in mouse embryonic fibroblasts, with inhibition modulated at protrusions and ruffles.
Journal ArticleDOI
Phototropin Blue-Light Receptors
TL;DR: The photochemical and biochemical events underlying phototropin activation are summarized in addition to the current knowledge of the molecular mechanisms associated with photoreceptor signaling.
Journal ArticleDOI
Structure and Function of Plant Photoreceptors
TL;DR: This work adopts the perspective of biophysicists interested in light-dependent signal transduction in nature and the three-dimensional structures that underpin signaling.
Journal ArticleDOI
TULIPs: Tunable, light-controlled interacting protein tags for cell biology
Devin Strickland,Yuan Lin,Elizabeth Wagner,C Matthew Hope,Josiah P. Zayner,Chloe Antoniou,Tobin R. Sosnick,Eric L. Weiss,Michael Glotzer +8 more
TL;DR: T tunable light-inducible dimerization tags (TULIPs) based on a synthetic interaction between the LOV2 domain of Avena sativa phototropin 1 and an engineered PDZ domain (ePDZ) are developed.
Journal ArticleDOI
Conformational switching in the fungal light sensor Vivid.
Brian D. Zoltowski,Carsten Schwerdtfeger,Carsten Schwerdtfeger,Joanne Widom,Joanne Widom,Jennifer J. Loros,Jennifer J. Loros,Alexandrine M. Bilwes,Alexandrine M. Bilwes,Jay C. Dunlap,Jay C. Dunlap,Brian R. Crane,Brian R. Crane +12 more
TL;DR: The Neurospora crassa photoreceptor Vivid tunes blue-light responses and modulates gating of the circadian clock and key elements of this activation mechanism are conserved by other photosensors such as White Collar-1, ZEITLUPE, ENVOY, and flavin-binding, kelch repeat, F-BOX 1.
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PAS Domains: Internal Sensors of Oxygen, Redox Potential, and Light
Barry L. Taylor,Igor B. Zhulin +1 more
TL;DR: PAS domains are newly recognized signaling domains that are widely distributed in proteins from members of the Archaea and Bacteria and from fungi, plants, insects, and vertebrates that function as input modules in proteins that sense oxygen, redox potential, light, and some other stimuli.
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The Photocycle of a Flavin-binding Domain of the Blue Light Photoreceptor Phototropin
Trevor E. Swartz,Stephanie B. Corchnoy,John M. Christie,James W. Lewis,Istvan Szundi,Winslow R. Briggs,Roberto A. Bogomolni +6 more
TL;DR: It has been shown that the metastable species is likely a flavin-cysteine (Cys39 thiol) adduct at the flavin C(4a) position, and Titrations of LOV2 using chromophore fluorescence as an indicator suggest that Cys39 exists as a thiolate.
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The LOV domain family: photoresponsive signaling modules coupled to diverse output domains.
TL;DR: The properties of the light, oxygen, or voltage (LOV) family of blue-light photoreceptor domains, a subset of the Per-ARNT-Sim (PAS) superfamily, are reviewed and the role of this conserved volume of structure in LOV-regulated processes is discussed.
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Blue-light photoreceptors in higher plants.
Winslow R. Briggs,Eva Huala +1 more
TL;DR: The carotenoid zeaxanthin may serve as the chromophore for a photoreceptor involved in blue-light-activated stomatal opening and some of the downstream events they are known to activate are discussed.