title: Mutational analysis of dimeric linkers in peri- and cytoplasmic domains of histidine kinase DctB reveals their functional roles in signal transduction.
abstract: Membrane-associated histidine kinases (HKs) in two-component systems respond to environmental stimuli by autophosphorylation and phospho-transfer. HK typically contains a periplasmic sensor domain that regulates the cytoplasmic kinase domain through a conserved cytoplasmic linker. How signal is transduced from the ligand-binding site across the membrane barrier remains unclear. Here, we analyse two linker regions of a typical HK, DctB. One region connects the first transmembrane helix with the periplasmic Per-ARNT-Sim domains, while the other one connects the second transmembrane helix with the cytoplasmic kinase domains. We identify a leucine residue in the first linker region to be essential for the signal transduction and for maintaining the delicate balance of the dimeric interface, which is key to its activities. We also show that the other linker, belonging to the S-helix coiled-coil family, plays essential roles in signal transduction inside the cell. Furthermore, by combining mutations with opposing activities in the two regions, we show that these two signalling transduction elements are integrated to produce a combined effect on the final activity of DctB.
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Life Sciences, Centre for Structural Biology, Imperial College London, London SW7 2AZ, UK xiaodong.zhang@imperial.ac.uk.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China wangyp@pku.edu.cn.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Wang
mesh_terms: D003593:Cytoplasm / Q000378:metabolism*; D004252:DNA Mutational Analysis; D000071677:Histidine Kinase; D006801:Humans; D008958:Models, Molecular; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000235:genetics*; D017434:Protein Structure, Tertiary / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*
chemical_list: D011494:Protein Kinases; D000071677:Histidine Kinase
keywords: DctB; transmembrane signal transduction; two-component system