Protein: Adaptive-response sensory kinase SasA (EC 2.7.13.3) (Sensor histidine kinase SasA) (Synechococcus adaptive sensor protein A) (SasA) (Q06904)
Organism: Synechococcus elongatus (strain ATCC 33912 / PCC 7942 / FACHB-805) (Anacystis nidulans R2)
Function: Member of the two-component regulatory system SasA/RpaA involved in genome-wide circadian gene expression. One of three clock output pathways. Participates in the KaiABC clock protein complex, which constitutes the main circadian regulator in cyanobacteria, via its interaction with KaiC. Required for robustness of the circadian rhythm of gene expression and involved in clock output. KaiC enhances the autophosphorylation activity of SasA, which then transfers its phosphate group to RpaA to activate it. Phosphotransfer is maximal when KaiC phosphorylation is active during the circadian cycle; this two-component system is activated by fully phosphorylated KaiC. A very robust clock is reconstituted with KaiA, KaiB, KaiC, SasA, CikA and RpaA; output is measured by transcription from an appropriate reporter. In addition to its output function, recruits fold-shifted KaiB (KaiB(fs)) to KaiC to cooperatively form the KaiB(6):KaiC(6) complex (independent of SasA kinase activity); at physiological concentrations increases their association. At higher concentrations SasA and KaiB(fs) compete to bind to KaiC. Mutations that decrease cooperativity nearly phenocopy a deletion mutation.
Sequence: MGESLSPQALAQPLLLQLFVDTRPLSQHIVQRVKNILAAVEATVPISLQVINVADQPQLVEYYRLVVTPALVKIGPGSRQVLSGIDLTDQLANQLPQWLVQQEAFFADREPPEVNIPFTELGQPETPALQQADAFFQLQQQYADLSERTKFLEQVIALVAHDLRNPLTAALLAVDTIQIRSQSFSVATAKEMQGLCSLFDQARSQLREIERMIAEILEATRHSGESLRINPREVVFEPLLQQVLEQLHERWRSKQQQLITDVPGDLPTLYADPDRLRQVLVNLLDNAIKYTPPGGTITIAALHRTSQKVQISISDTGSGIPRDQLSVIFKNLVRLSRDSSQEGYGIGLSVCQRIVQAHFGRIWVASELGQGSTFHFTMPVYRYTMPC
InterPro domains: - IPR036890: Histidine kinase/HSP90-like ATPase superfamily (homologous_superfamily) [215-384]
- IPR036249: Thioredoxin-like superfamily (homologous_superfamily) [5-102]
- IPR023527: Adaptive-response sensory-kinase SasA (family) [8-382]
- IPR003594: Histidine kinase/HSP90-like ATPase domain (domain) [271-382]
- IPR005467: Histidine kinase domain (domain) [158-382]
- IPR011649: KaiB domain (domain) [17-98]
- IPR036097: Signal transduction histidine kinase, dimerisation/phosphoacceptor domain superfamily (homologous_superfamily) [137-223]
- IPR004358: Signal transduction histidine kinase-related protein, C-terminal (domain) [309-379]
- IPR003661: Signal transduction histidine kinase, dimerisation/phosphoacceptor domain (domain) [151-225]
Interaction partners: - DNA-binding dual master transcriptional regulator RpaA
- Circadian clock oscillator protein KaiC
- Response regulator receiver domain protein
- Two component transcriptional regulator, LuxR family
- Probable transcriptional regulator ycf27
- Probable transcriptional regulator ycf27
- Potassium-transporting ATPase D chain
- Diguanylate cyclase with GAF sensor
- histidine kinase
- Two component transcriptional regulator, winged helix family
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0005515 (protein binding), GO:0042802 (identical protein binding)
Biological Process (BP): GO:0008150 (biological process), GO:0065007 (biological regulation), GO:0048511 (rhythmic process), GO:0050789 (regulation of biological process), GO:0050794 (regulation of cellular process), GO:0019222 (regulation of metabolic process), GO:0007623 (circadian rhythm), GO:0060255 (regulation of macromolecule metabolic process), GO:0031323 (regulation of cellular metabolic process), GO:0080090 (regulation of primary metabolic process), GO:0009889 (regulation of biosynthetic process), GO:0051171 (regulation of nitrogen compound metabolic process), GO:0034248 (regulation of amide metabolic process), GO:0010556 (regulation of macromolecule biosynthetic process), GO:0051246 (regulation of protein metabolic process), GO:0010468 (regulation of gene expression), GO:0031326 (regulation of cellular biosynthetic process), GO:0006417 (regulation of translation), GO:0010608 (post-transcriptional regulation of gene expression), GO:2000112 (regulation of cellular macromolecule biosynthetic process)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0043229 (intracellular organelle), GO:0043228 (non-membrane-bounded organelle), GO:0043232 (intracellular non-membrane-bounded organelle), GO:0031469 (bacterial microcompartment), GO:0031470 (carboxysome)