User:Cboursnell/Sandbox/5TM-5TMR LYT

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Symbol 5TM-5TMR_LYT
Pfam PF07694
Pfam clan CL0315
InterPro IPR011620

Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions.[1] Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk.[2] These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more.[3] Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR).[4] The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.

A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response.[5][6]

Signal transducing histidine kinases are the key elements in two-component signal transduction systems, which control complex processes such as the initiation of development in microorganisms.[7][8] Examples of histidine kinases are EnvZ, which plays a central role in osmoregulation,[9] and CheA, which plays a central role in the chemotaxis system.[10] Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present. The kinase domain is responsible for the autophosphorylation of the histidine with ATP, the phosphotransfer from the kinase to an aspartate of the response regulator, and (with bifunctional enzymes) the phosphotransfer from aspartyl phosphate back to ADP or to water.[11] The kinase core has a unique fold, distinct from that of the Ser/Thr/Tyr kinase superfamily.

HKs can be roughly divided into two classes: orthodox and hybrid kinases.[12][13] Most orthodox HKs, typified by the Escherichia coli EnvZ protein, function as periplasmic membrane receptors and have a signal peptide and transmembrane segment(s) that separate the protein into a periplasmic N-terminal sensing domain and a highly conserved cytoplasmic C-terminal kinase core. Members of this family, however, have an integral membrane sensor domain. Not all orthodox kinases are membrane bound, e.g., the nitrogen regulatory kinase NtrB (GlnL) is a soluble cytoplasmic HK.[4] Hybrid kinases contain multiple phosphodonor and phosphoacceptor sites and use multi-step phospho-relay schemes instead of promoting a single phosphoryl transfer. In addition to the sensor domain and kinase core, they contain a CheY-like receiver domain and a His-containing phosphotransfer (HPt) domain.

This entry represents the transmembrane region of the 5TM-Lyt (5TM Receptors of the LytS-YhcK type) histidine kinase.[14] The two-component regulatory system LytS/LytT probably regulates genes involved in cell wall metabolism.


  1. ^ Skerker JM, Prasol MS, Perchuk BS, Biondi EG, Laub MT (2005). "Two-component signal transduction pathways regulating growth and cell cycle progression in a bacterium: a system-level analysis". PLoS Biol. 3 (10): e334. PMC 1233412Freely accessible. PMID 16176121. doi:10.1371/journal.pbio.0030334.  Unknown parameter |month= ignored (help)
  2. ^ Laub MT, Goulian M (2007). "Specificity in two-component signal transduction pathways". Annu. Rev. Genet. 41: 121–45. PMID 18076326. doi:10.1146/annurev.genet.41.042007.170548.  C1 control character in |pages= at position 5 (help)
  3. ^ Wolanin PM, Thomason PA, Stock JB (2002). "Histidine protein kinases: key signal transducers outside the animal kingdom". Genome Biol. 3 (10): REVIEWS3013. PMC 244915Freely accessible. PMID 12372152.  Unknown parameter |month= ignored (help)
  4. ^ a b Stock AM, Robinson VL, Goudreau PN (2000). "Two-component signal transduction". Annu. Rev. Biochem. 69: 183–215. PMID 10966457. doi:10.1146/annurev.biochem.69.1.183.  C1 control character in |pages= at position 5 (help)
  5. ^ Varughese KI (2002). "Molecular recognition of bacterial phosphorelay proteins". Curr. Opin. Microbiol. 5 (2): 142–8. PMID 11934609.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  6. ^ Hoch JA, Varughese KI (2001). "Keeping signals straight in phosphorelay signal transduction". J. Bacteriol. 183 (17): 4941–9. PMC 95367Freely accessible. PMID 11489844.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 6 (help)
  7. ^ Perego M, Hoch JA (1996). "Protein aspartate phosphatases control the output of two-component signal transduction systems". Trends Genet. 12 (3): 97–101. PMID 8868347.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 4 (help)
  8. ^ West AH, Stock AM (2001). "Histidine kinases and response regulator proteins in two-component signaling systems". Trends Biochem. Sci. 26 (6): 369–76. PMID 11406410.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  9. ^ Tomomori C, Tanaka T, Dutta R, Park H, Saha SK, Zhu Y, Ishima R, Liu D, Tong KI, Kurokawa H, Qian H, Inouye M, Ikura M (1999). "Solution structure of the homodimeric core domain of Escherichia coli histidine kinase EnvZ". Nat. Struct. Biol. 6 (8): 729–34. PMID 10426948. doi:10.1038/11495.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  10. ^ Bilwes AM, Alex LA, Crane BR, Simon MI (1999). "Structure of CheA, a signal-transducing histidine kinase". Cell. 96 (1): 131–41. PMID 9989504.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  11. ^ Vierstra RD, Davis SJ (2000). "Bacteriophytochromes: new tools for understanding phytochrome signal transduction". Semin. Cell Dev. Biol. 11 (6): 511–21. PMID 11145881. doi:10.1006/scdb.2000.0206.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  12. ^ Alex LA, Simon MI (1994). "Protein histidine kinases and signal transduction in prokaryotes and eukaryotes". Trends Genet. 10 (4): 133–8. PMID 8029829.  Unknown parameter |month= ignored (help); C1 control character in |pages= at position 5 (help)
  13. ^ Parkinson JS, Kofoid EC (1992). "Communication modules in bacterial signaling proteins". Annu. Rev. Genet. 26: 71–112. PMID 1482126. doi:10.1146/  C1 control character in |pages= at position 4 (help)
  14. ^ Anantharaman V, Aravind L (2003). "Application of comparative genomics in the identification and analysis of novel families of membrane-associated receptors in bacteria". BMC Genomics. 4 (1): 34. PMC 212514Freely accessible. PMID 12914674. doi:10.1186/1471-2164-4-34.  Unknown parameter |month= ignored (help)

This article incorporates text from the public domain Pfam and InterPro IPR011620

Category:Protein domains