The ancestral symbiont sensor kinase CSK links photosynthesis with gene expression in chloroplasts.
We describe a novel, typically prokaryotic, sensor kinase in chloroplasts of green plants. The gene for this chloroplast sensor kinase (CSK) is found in cyanobacteria, prokaryotes from which chloroplasts evolved. The CSK gene has moved, during evolution, from the ancestral chloroplast to the nuclear genomes of eukaryotic algae and green plants. The CSK protein is now synthesised in the cytosol of photosynthetic eukaryotes and imported into their chloroplasts as a protein precursor. In the model higher plant Arabidopsis thaliana, CSK is autophosphorylated and required for control of transcription of chloroplast genes by the redox state of an electron carrier connecting photosystems I and II. CSK therefore provides a redox regulatory mechanism that couples photosynthesis to gene expression. This mechanism is inherited directly from the cyanobacterial ancestor of chloroplasts, is intrinsic to chloroplasts, and is targeted to chloroplast genes.
Puthiyaveetil
Sujith
S
School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom.
Kavanagh
T Anthony
TA
Cain
Peter
P
Sullivan
James A
JA
Newell
Christine A
CA
Gray
John C
JC
Robinson
Colin
C
van der Giezen
Mark
M
Rogers
Matthew B
MB
Allen
John F
JF
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics*; D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D000071677:Histidine Kinase / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000235:genetics*; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013559:Symbiosis; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; C000615593:chloroplast sensor kinase, Arabidopsis