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Searching for the mechanism of signalling by plant photoreceptor cryptochrome.

TitleSearching for the mechanism of signalling by plant photoreceptor cryptochrome.
Publication TypeJournal Article
Year of Publication2015
AuthorsMüller, P, Bouly, J-P
JournalFEBS Lett
Date Published2015 Jan 16
KeywordsCryptochromes, Plant Proteins, Plants, Protein Binding, Signal Transduction, Transcription Factors

Even though the plant photoreceptors cryptochromes were discovered more than 20 years ago, the mechanism through which they transduce light signals to their partner molecules such as COP1 (Constitutive Photomorphogenic 1) or SPA1 (Suppressor of Phytochrome A) still remains to be established. We propose that a negative charge induced by light in the vicinity of the flavin chromophore initiates cryptochrome 1 signalling. This negative charge might expel the protein-bound ATP from the binding pocket, thereby pushing off the C-terminus that covers the ATP pocket in the dark state of the protein. This conformational change should allow for phosphorylation of previously inaccessible amino acids. A partially phosphorylated 'ESSSSGRR-VPE' fragment of the C-terminus could mimic the sequence of the transcription factor HY5 that is essential for binding to the negative regulator of photomorphogenesis COP1. HY5 release through competition for the COP1 binding site could represent the long-sought connection between light activation of cryptochrome and modulation of photomorphogenesis.

Alternate JournalFEBS Lett.
PubMed ID25500270