Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using the Arabidopsis ethylene receptor ETR1 as a probe, we have isolated a tomato homologue (tETR) from a ripening cDNA library. The predicted amino acid sequence is 70% identical to ETR1 and homologous to a variety of bacterial two component response regulators over the histidine kinase domain. Sequencing of four separate cDNAs indicates that tETR lacks the carboxyl terminal response domain and is identical to that encoded by the tomato Never ripe gene. Ribonuclease protection showed tETR mRNA was undetectable in unripe fruit or pre-senescent flowers, increased in abundance during the early stages of ripening, flower senescence, and in abscission zones, and was greatly reduced in fruit of ripening mutants deficient in ethylene synthesis or response. These results suggest that changes in ethylene sensitivity are mediated by modulation of receptor levels during development.
Plant Mol Biol 1996 Sep
PMID:Ethylene receptor expression is regulated during fruit ripening, flower senescence and abscission. 891 38

In Escherichia coli, EnvZ senses changes in the osmotic conditions of the growth environment and controls the phosphorylated state of the regulatory protein, OmpR. OmpR-phosphate regulates the expression of the porin genes, ompF and ompC. To investigate the role of the periplasmic domain of EnvZ in sensing of osmolarity signals, portions of this domain were deleted. Cells containing the EnvZ mutant proteins were able to regulate normally the production of OmpF and OmpC in response to changes in osmolarity. The periplasmic domain of EnvZ was also replaced with the non-homologous periplasmic domain of the histidine kinase PhoR of Bacillus subtilis. Osmoregulation of OmpF and OmpC production in cells containing the PhoR-EnvZ hybrid protein was indistinguishable from that in cells containing wild-type EnvZ. Identical results were obtained with an envZ-pta/ack strain, which could not synthesize acetyl phosphate. Thus, acetyl phosphate was not involved in the regulation of ompF and ompC observed in this study. These results indicate that the periplasmic domain of EnvZ is not essential for sensing of osmolarity signals.
Mol Microbiol 1996 Nov
PMID:Re-examination of the role of the periplasmic domain of EnvZ in sensing of osmolarity signals in Escherichia coli. 893 25

The czc determinant, which mediates resistance to Co2+, Zn2+ and Cd2+ in Alcaligenes eutrophus CH34 by cation efflux, is regulated by a two-component regulatory system composed of the sensor histidine kinase CzcS and the response activator CzcR (in addition to other components previously described). Regulatory genes are arranged in an upstream regulatory region (URR) and a downstream regulatory region (DRR). Transcription of czcCBA and of the URR was regulated by heavy-metal cations. DNA sequencing of the region downstream of czcD revealed the presence of the czcR and czcS genes which together with czcD form the DRR. Regulation of the DRR was studied with a czcD::lacZ translational fusion and a czcS::lux transcriptional fusion. Expression of both genes is also regulated by heavy metals. The genes of the URR yielded three mRNAs of approx. 1200, 500 and 200 nucleotides, respectively. The genes czcCBA for the cation/proton antiporter CzcCBA were transcribed by one operon as a transcript of 6200 nucleotides.
Mol Microbiol 1997 Feb
PMID:Two-component regulatory system involved in transcriptional control of heavy-metal homoeostasis in Alcaligenes eutrophus. 904 83

The membrane-anchored DjIA protein represents the third member of the DnaJ 'J-domain' family of Escherichia coli that includes DnaJ and CbpA. DjIA possesses a J-domain at its extreme C-terminus but shares no additional homology with DnaJ. Our genetic analysis suggests that DjIA acts in concert with the RcsB/C two-component signal transduction system to augment induction of the cps (capsular polysaccharide) operon and synthesis of colanic acid mucoid capsule. The DjIA J-domain is essential for the observed stimulation of this pathway as deletion, or introduction of the mutation H233Q, within the highly conserved HPD tripeptide abolished all inducing activity. Deletion of the transmembrane anchor sequence also abolished all inducing activity. djIA is not an essential gene under all conditions tested, nor is it essential for mucoid capsule biosynthesis; however, strong overexpression leads to rapid loss of cell viability suggesting that the gene is normally tightly regulated. Northern analysis revealed that djIA message was extremely unstable but could be induced or stabilized in response to cold shock. The activation of the cps operon by DjIA is dependent upon both DnaK(Hsp70) and GrpE, and therefore we propose a role for DjIA, together with this chaperone machine, as a novel regulator of a two-component histidine kinase signal transduction pathway.
Mol Microbiol 1997 Sep
PMID:Positive control of the two-component RcsC/B signal transduction network by DjlA: a member of the DnaJ family of molecular chaperones in Escherichia coli. 936 17

Production of the bacteriocin sakacin P by Lactobacillus sake LTH673 is dependent on a secreted 19-residue peptide pheromone (IP-673). The gene encoding IP-673 (sppIP) was identified and sequenced. SppIP was shown to be co-transcribed with genes encoding a histidine kinase (sppK) and a response regulator (sppR) typical for signal transduction in bacteria. Further sequencing and transcription studies have shown that IP-673 induces transcription of its own gene and of what are often considered to be all genes necessary for bacteriocin production and immunity. Studies with a reporter gene showed that the promoter in front of the sakacin P structural gene (sppA) is strictly regulated. The promoter in front of sppIP turned out to be less strictly regulated, and low basal promoter activity could be detected in uninduced cells. Bacteriocin production in Bac isolates of L. plantarum C11 could be induced by the non-cognate IP-673 only after the introduction of sppK, indicating that sppK encodes the pheromone receptor. These results show that bacteriocin production in lactobacilli is regulated using a short, strain-specific peptide pheromone. Growth conditions were shown to have considerable effects on the functionality of this regulatory mechanism.
Mol Microbiol 1997 Oct
PMID:Pheromone-induced production of antimicrobial peptides in Lactobacillus. 938 59

Multiple isoforms of type 1 hexokinase (HK1) are transcribed during spermatogenesis in the mouse, including at least three that are presumably germ cell specific: HK1-sa, HK1-sb, and HK1-sc. Each of these predicted proteins contains a common, germ cell-specific sequence that replaces the porin-binding domain found in somatic HK1. Although HK1 protein is present in mature sperm and is tyrosine phosphorylated, it is not known whether the various potential isoforms are differentially translated and localized within the developing germ cells and mature sperm. Using antipeptide antisera against unique regions of HK1-sa and HK1-sb, it was demonstrated that these isoforms were not found in pachytene spermatocytes, round spermatids, condensing spermatids, or sperm, suggesting that HK1-sa and HK1-sb are not translated during spermatogenesis. Immunoreactivity was detected in protein from round spermatids, condensing spermatids, and mature sperm using an antipeptide antiserum against the common, germ cell-specific region, suggesting that HK1-sc was the only germ cell-specific isoform present in these cells. Two-dimensional SDS-PAGE suggested that all of the sperm HK1-sc was tyrosine phosphorylated, and that the somatic HK1 isoform was not present. Immunoelectron microscopy revealed that HK1-sc was associated with the mitochondria and with the fibrous sheath of the flagellum and was found in discrete clusters in the region of the membranes of the sperm head. The unusual distribution of HK1-sc in sperm suggests novel functions, such as extramitochondrial energy production, and also demonstrates that a hexokinase without a classical porin-binding domain can localize to mitochondria.
Mol Biol Cell 1998 Feb
PMID:Targeting of a germ cell-specific type 1 hexokinase lacking a porin-binding domain to the mitochondria as well as to the head and fibrous sheath of murine spermatozoa. 945 Sep 53

Unique type 1 hexokinase (HK1) mRNAs are present in mouse spermatogenic cells (mHk1-s). They encode a spermatogenic cell-specific sequence region (SSR) but not the porin-binding domain (PBD) necessary for HK1 binding to porin on the outer mitochondrial membrane. This study determined the origin of the multiple Hk1-s transcripts in mouse spermatogenic cells and verified that they are translated in mouse spermatogenic cells. It also showed that a single mHk1 gene encodes the mHk1 transcripts of somatic cells and the mHk1-sa and mHk1-sb transcripts of spermatogenic cells, that alternative exons are used during mHk1 gene expression in mouse spermatogenic cells, and that mHK1-S is translated in mouse spermatogenic cells and is localized mainly with the fibrous sheath in the tail region, not with the mitochondria in the midpiece of mouse sperm.
Mol Reprod Dev 1998 Apr
PMID:Mouse spermatogenic cell-specific type 1 hexokinase (mHk1-s) transcripts are expressed by alternative splicing from the mHk1 gene and the HK1-S protein is localized mainly in the sperm tail. 950 88

Despite the presence of highly conserved signalling modules, significant cross-communication between different two-component systems has only rarely been observed. Domain swapping and the characterization of liberated signalling modules enabled us to characterize in vitro the protein domains that mediate specificity and are responsible for the high fidelity in the phosphorelay of the unorthodox Bvg and Evg two-component systems. Under equimolar conditions, significant in vitro phosphorylation of purified BvgA and EvgA proteins was only obtained by their histidine kinases, BvgS and EvgS respectively. One hybrid histidine kinase consisting of the BvgS transmitter and HPt domains and of the EvgS receiver domain (BvgS-TO-EvgS-R) was able to phosphorylate BvgA but not EvgA. In contrast, the hybrid protein consisting of the BvgS transmitter and the EvgS receiver and HPt domains (BvgS-T-EvgS-RO) was unable to phosphorylate BvgA but efficiently phosphorylated EvgA. These results demonstrate that the C-terminal HPt domains of the sensor proteins endow the unorthodox two-component systems with a high specificity for the corresponding regulator protein. In the case of the response regulators, the receiver but not the output domains contribute to the specific interaction with the histidine kinases, because a hybrid protein consisting of the EvgA receiver and the BvgA output domain could only be phosphorylated by the EvgS protein.
Mol Microbiol 1998 Mar
PMID:Specificity of the BvgAS and EvgAS phosphorelay is mediated by the C-terminal HPt domains of the sensor proteins. 953 79

Bacteria use different strategies to navigate to niches where environmental factors are favourable for growth. Chemotaxis is a behavioural response mediated by specific receptors that sense the concentration of chemicals in the environment. Recently, a new type of sensor has been described in Escherichia coli that responds to changes in cellular energy (redox) levels. This sensor, Aer, guides the bacteria to environments that support maximal energy levels in the cells. A variety of stimuli, such as oxygen, alternative electron acceptors, light, redox carriers that interact with the electron transport system and metabolized carbon sources, effect changes in the cellular energy (redox) levels. These changes are detected by Aer and by the serine chemotaxis receptor Tsr and are transduced into signals that elicit appropriate behavioural responses. Diverse environmental signals from Aer and chemotaxis receptors converge and integrate at the level of the CheA histidine kinase. Energy sensing is widespread in bacteria, and it is now evident that a variety of signal transduction strategies are used for the metabolism-dependent behaviours. The occurrence of putative energy-sensing domains in proteins from cells ranging from Archaea to humans indicates the importance of this function for all living systems.
Mol Microbiol 1998 May
PMID:In search of higher energy: metabolism-dependent behaviour in bacteria. 964 37

Antidote/toxin gene pairs known as "addiction modules" can maintain plasmids in bacterial populations by means of post-segregational killing. However, several chromosome-encoded addiction modules may provide an entirely distinct function in the programmed cell death of moribund subpopulations under starvation conditions. We now report a novel chromosomal bacteriolytic module of Escherichia coli called the entericidin locus, which is activated in stationary phase under high osmolarity conditions by sigmaS and simultaneously repressed by the osmoregulatory EnvZ/OmpR signal transduction pathway. The entericidin locus encodes tandem paralogous genes (ecnAB) and directs the synthesis of two small cell-envelope lipoproteins. An attenuator precedes ecnA and an ompR-sensitive sigmaS promoter governs expression of ecnB. The entericidin A lipoprotein is an antidote to the bacteriolytic lipoprotein entericidin B. The entericidins are predicted to adopt amphipathic alpha-helical structures and to reciprocally modulate membrane stability. The entericidin locus is not present on any known plasmids, but is conserved in the homologous region of the Citrobacter freundii chromosome. Although the cloned C. freundii entericidin locus is expressed in E. coli independently of ompR, it carries an additional ompR-like gene called ecnR. The organization of the entericidin locus as a chromosomal antidote/toxin gene pair, which is regulated by both positive and negative osmotic signals during starvation, is consistent with an emerging paradigm of programmed bacterial cell death.
J Mol Biol 1998 Jul 24
PMID:The entericidin locus of Escherichia coli and its implications for programmed bacterial cell death. 967 90


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