TY - JOUR AU - Wolanin, Peter M. AU - Thomason, Peter A. AU - Stock, Jeffry B. PY - 2002 DA - 2002/09/25 TI - Histidine protein kinases: key signal transducers outside the animal kingdom JO - Genome Biology SP - reviews3013.1 VL - 3 IS - 10 AB - 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. SN - 1474-760X UR - https://doi.org/10.1186/gb-2002-3-10-reviews3013 DO - 10.1186/gb-2002-3-10-reviews3013 ID - Wolanin2002 ER -