Protein kinase CK2 interacts with and phosphorylates the Arabidopsis circadian clock-associated 1 protein

• Published in: Proceedings of the National Academy of Sciences - PNAS 1998-09, Vol.95 (18), p.11020-11025
• Main Authors: Sugano, S. (University of California, Los Angeles, CA.), Andronis, C, Green, R.M, Wang, Z.Y, Tobin, E.M
• Format: Article
• Language: English
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN; Amino Acid Sequence; AMINO ACID SEQUENCES; Amino acids; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins; ARABIDOPSIS THALIANA; Base Sequence; BINDING; Biological Sciences; Botany; Casein Kinase II; CHEMICAL COMPOSITION; Circadian Rhythm; COMPLEMENTARY DNA; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; DNA; DNA, Complementary; DNA, Recombinant; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; ENZYMIC ACTIVITY; ESTIMULO; FACTEUR DE TRANSCRIPTION; FACTORES DE TRANSCRIPCION; FOSFORILACION; GENBANK/AF068318; Gene expression regulation; Genes; Goods and services tax; MOLECULAR SEQUENCE DATA; NUCLEOTIDE SEQUENCE; PHOSPHORYLATION; Plant cells; Plasmids; Promoter Regions, Genetic; PROMOTERS; Protein Binding; PROTEIN KINASE; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; PROTEINA QUINASA; PROTEINE KINASE; Proteins; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; SECUENCIA NUCLEOTIDICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; STIMULI; STIMULUS; TRANSCRIPTION FACTORS; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.95.18.11020

The circadian clock-associated 1 (CCA1) gene encodes a Myb-related transcription factor that has been shown to be involved in the phytochrome regulation of Lhcbl*3 gene expression and in the functional of the circadian oscillator in Arabidopsis thaliana. By using a yeast interaction screen to identify proteins that interact with CCA1 we have isolated a cDNA clone encoding a regulatory (beta) subunit of the protein kinase CK2 and have designated it as CKB3. CKB3 is the only reported example of a third beta-subunit of CK2 found in any organism. CKB3 interacts specifically with CCA1 both in a yeast two-hybrid system and in an in vitro interaction assay. Other subunits of CK2 also show an interaction with CCA1 in vitro. CK2 beta-subunits stimulate binding of CCA1 to the CCA1 binding site on the Lhcbl*3 gene promoter, and recombinant CK2 is able to phosphorylate CCA1 in vitro. Furthermore, Arabidopsis plant extracts contain a CK2-like activity that affects the formation of a DNA-protein complex containing CCA1. These results suggest that CK2 can modulate CCA1 activity both by direct interaction and by phosphorylation of the CCA1 protein and that CK2 may play a role in the function of CCA1 in vivo