The mechanism of signal transduction by two-component systems.
Two-component systems, composed of a homodimeric histidine kinase (HK) and a response regulator (RR), are major signal transduction devices in bacteria. Typically the signal triggers HK autophosphorylation at one His residue, followed by phosphoryl transfer from the phospho-His to an Asp residue in the RR. Signal extinction frequently involves phospho-RR dephosphorylation by a phosphatase activity of the HK. Our understanding of these reactions and of the determinants of partner specificity among HK-RR couples has been greatly increased by recent crystal structures and biochemical experiments on HK-RR complexes. Cis-autophosphorylation (one subunit phosphorylates itself) occurs in some HKs while trans-autophosphorylation takes place in others. We review and integrate this new information, discuss the mechanism of the three reactions and propose a model for transmembrane signaling by these systems.
Casino
Patricia
P
Instituto de Biomedicina de Valencia-Consejo Superior de Investigaciones Científicas (IBV-CSIC) and Centro de Investigaciones en Red de Enfermedades Raras (CIBERER-ISCIII), Jaume Roig 11, Valencia 46010, Spain.
Rubio
Vicente
V
Marina
Alberto
A
D003593:Cytoplasm / Q000378:metabolism; D000071677:Histidine Kinase; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction
D011494:Protein Kinases; D000071677:Histidine Kinase; D010744:Phosphoric Monoester Hydrolases