title: Histidine protein kinases: key signal transducers outside the animal kingdom.
abstract: Histidine protein kinases (HPKs) are a large family of signal-transduction enzymes that autophosphorylate on a conserved histidine residue. HPKs form two-component signaling systems together with their downstream target proteins, the response regulators, which have a conserved aspartate in a so-called 'receiver domain' that is phosphorylated by the HPK. Two-component signal transduction is prevalent in bacteria and is also widely used by eukaryotes outside the animal kingdom. The typical HPK is a transmembrane receptor with an amino-terminal extracellular sensing domain and a carboxy-terminal cytosolic signaling domain; most, if not all, HPKs function as dimers. They show little similarity to protein kinases that phosphorylate serine, threonine or tyrosine residues, but may share a distant evolutionary relationship with these enzymes. In excess of a thousand known genes encode HPKs, which are important for multiple functions in bacteria, including chemotaxis and quorum sensing, and in eukaryotes, including hormone-dependent developmental processes. The proteins divide into at least 11 subfamilies, only one of which is present in eukaryotes, suggesting that lateral gene transfer gave rise to two-component signaling in these organisms.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA. jstock@princeton.edu
authors.forename: Peter M
authors.initials: PM
authors.lastname: Wolanin
authors.forename: Peter A
authors.initials: PA
authors.lastname: Thomason
authors.forename: Jeffry B
authors.initials: JB
authors.lastname: Stock
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D005057:Eukaryotic Cells / Q000201:enzymology; D019143:Evolution, Molecular; D000071677:Histidine Kinase; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000201:enzymology; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D011956:Receptors, Cell Surface; D011494:Protein Kinases; D000071677:Histidine Kinase