The signaling mechanism of Arabidopsis CRY1 involves direct interaction with COP1.
Dark-grown transgenic Arabidopsis seedlings expressing the C-terminal domains (CCT) of the cryptochrome (CRY) blue light photoreceptors exhibit features that are normally associated only with light-grown seedlings, indicating that the signaling mechanism of Arabidopsis CRY is mediated through CCT. The phenotypic properties mediated by CCT are remarkably similar to those of the constitutive photomorphogenic1 (cop1) mutants. Here we show that Arabidopsis cryptochrome 1 (CRY1) and its C-terminal domain (CCT1) interacted strongly with the COP1 protein. Coimmunoprecipitation studies showed that CRY1 was bound to COP1 in extracts from both dark- and light-grown Arabidopsis. An interaction also was observed between the C-terminal domain of Arabidopsis phytochrome B and COP1, suggesting that phytochrome signaling also proceeds, at least in part, through direct interaction with COP1. These findings give new insight into the initial step in light signaling in Arabidopsis, providing a molecular link between the blue light receptor, CRY1, and COP1, a negative regulator of photomorphogenesis.
Yang
H Q
HQ
Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018, USA.
Tang
R H
RH
Cashmore
A R
AR
D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins; D019843:Archaeal Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D018506:Gene Expression Regulation, Plant; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008027:Light; D008954:Models, Biological; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D010786:Photoreceptor Cells; D017956:Photoreceptor Cells, Invertebrate; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism; D051939:Phytochrome B; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017354:Point Mutation; D011485:Protein Binding; D025941:Protein Interaction Mapping; D043562:Receptors, G-Protein-Coupled; D012441:Saccharomyces cerevisiae / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D019843:Archaeal Proteins; C538962:CRY1 protein, Arabidopsis; C538963:CRY1 protein, human; D002352:Carrier Proteins; C108618:Cct2 protein, Haloferax volcanii; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C497952:PHYB protein, Arabidopsis; D010940:Plant Proteins; D043562:Receptors, G-Protein-Coupled; D014157:Transcription Factors; C119828:cry protein, Drosophila; D010834:Phytochrome; D051939:Phytochrome B; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases