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J Biol Chem, Vol. 273, Issue 49, 32864-32869, December 4, 1998


Signal Decay through a Reverse Phosphorelay in the Arc Two-component Signal Transduction System*

Dimitris GeorgellisDagger , Ohsuk Kwon, Peter De Wulf, and E. C. C. Lin§

From the Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115

    ABSTRACT
Top
Abstract
Introduction
Procedures
Results
Discussion
References

Escherichia coli senses and signals anoxic or low redox conditions in its growth environment by the Arc two-component system. Under those conditions, the tripartite sensor kinase ArcB undergoes autophosphorylation at the expense of ATP and subsequently transphosphorylates its cognate response regulator ArcA through a His right-arrow Asp right-arrow His right-arrow Asp phosphorelay pathway. In this study we used various combinations of wild-type and mutant ArcB domains to analyze in vitro the pathway for signal decay. The results indicate that ArcA-P dephosphorylation does not occur by direct hydrolysis but by transfer of the phosphoryl group to the secondary transmitter and subsequently to the receiver domain of ArcB. This reverse phosphorelay involves both the conserved His-717 of the secondary transmitter domain and the conserved Asp-576 of the receiver domain of ArcB but not the conserved His-292 of its primary transmitter domain. This novel pathway for signal decay may generally apply to signal transduction systems with tripartite sensor kinases.

    INTRODUCTION
Top
Abstract
Introduction
Procedures
Results
Discussion
References

Signal transduction by phosphorylation and dephosphorylation of cellular proteins plays pivotal roles in regulating numerous cellular processes in both prokaryotes and eukaryotes. In prokaryotes, signaling by phosphoryl group transfer reactions depends on two-component systems typically comprising a sensor kinase and its cognate response regulator (1). Upon stimulation, the sensor kinase undergoes ATP-dependent autophosphorylation at a conserved histidine. The kinase then activates its cognate response regulator by transphosphorylating it at a conserved aspartate. Often, the kinase exhibits a third activity that promotes the release of Pi from the phospho-response regulator. Such two-component systems have also been found in archaebacteria (2, 3), fungi (4-6), and the plant Arabidopsis thaliana (7-9).

The Arc (anoxic redox control, formerly aerobic respiration control) two-component system of Escherichia coli consists of ArcB as the membrane-bound sensor kinase and ArcA as its response regulator (Fig. 1). This system regulates the expression of some 30 operons (the Arc modulon) in response to redox conditions of growth (10, 11). The ArcB protein (12, 13) belongs to a subfamily of tripartite hybrid kinases (14); in addition to the canonical pair of transmembrane segments and the orthodox transmitter domain (H1), there is a central receiver domain (D1) and a secondary C-terminal transmitter domain (H2) (15, 16). This subfamily accounts for about 20% of the currently reported sensor kinases in E. coli (17). Other examples of bacterial tripartite kinases include BarA (18), BvgS (19), EvgS (20), LemA (21), RteA (22), and TorS (23).


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  		Fig. 1.   Schematic representations of protein domains of the Arc two-component system. Top, the ArcB sensor kinase protein. Two N-terminal transmembrane segments (TM) were predicted on the basis of a hydrophobicity plot (61) and supported by ArcB-PhoA fusion analyses (O. Kwon and D. Georgellis, unpublished data.) (62). Residues 73-115 contain a putative leucine zipper motif (63). H1 (the orthodox transmitter domain) is shown with the conserved His-292 (12) and the catalytic determinants N, G1, and G2. The last two determinants resemble nucleotide-binding motifs (64). D1 (the receiver domain) is shown with the conserved Asp-576 (12), and H2 (the secondary transmitter domain) is shown with the conserved His-717 (15). The hatched bars indicate the lengths of the individual H1, D1, and H2 modules used in the study. Not illustrated are H1-D1 comprising residues 78-661, and D1-H2 comprising residues 521-778. Bottom, the ArcA response regulator protein. The N-terminal receiver domain contains the conserved Asp-54, and the C-terminal domain contains the helix-turn-helix (HTH) motif (65). The hatched bar indicates the length of ArcA'.

Results from a previous in vitro study on the Arc system indicated that, following ArcB autophosphorylation at the conserved His-292 of H1, the phosphoryl group is successively transferred to the conserved Asp-576 of D1, the conserved His-717 of H2, and the conserved Asp-54 of ArcA in a His right-arrow Asp right-arrow His right-arrow Asp phosphorelay (24). This sequence of signal transmission was previously reported for the Kin/Spo system of Bacillus subtilis (25), the Sln1p/Ypd1p/Ssk1p of Saccharomyces cerevisiae (26), the BvgS/A of Bordetella pertussis (27, 28), and the TorS/R of E. coli (29).

So far most studies on these signal transduction pathways have focused on the ATP-dependent autophosphorylation of the sensor kinase and the subsequent phosphotransfer reaction(s) to the response regulator. Considerably less is known about the pathways for signal decay that are equally important in adaptive responses. Here we report experiments designed to analyze the route of ArcA-P dephosphorylation. The results led us to propose a novel pathway for signal decay.

    EXPERIMENTAL PROCEDURES
Top
Abstract
Introduction
Procedures
Results
Discussion
References

Bacterial Strains, Plasmids, and Oligonucleotides-- E. coli M15 and plasmids pREP4 and pQE30 were obtained from Qiagen Ltd. Plasmids pQE30ArcB78-778, pQE30ArcB78-661, pQE30ArcB78-520, pQE30ArcB521-778, pQE30ArcB521-661, pQE30ArcB638-778, and pQE30ArcA, used for expression of His-tagged derivatives of ArcB and ArcA, have been described previously (24, 30). To create pQE30ArcA', a 440-base pair region of DNA containing the coding sequence corresponding to amino acid residues 1-136 of ArcA was amplified by the PCR1 using primers 5'-CCCGGATCCCATATGCAGACCCCGCACATTCTTATC-3' and 5'-CCCGGATCCTGCAGTCATTAGCTTTCAACGCTACGACGTTCTTC-3' with pMW2 (10) as template. The PCR product was digested with BamHI and PstI, and the resulting fragment was cloned between the BamHI and PstI sites of pQE30.

To create pQE30ArcB521-778, D576A, primers 5'-CCCGGATCCCATATGCCTTTACCGGCGCTGAATGTGC-3' and 5'-CCCGGATCCATGCATCGCGCACCCCGGTCTAGCC-3' were used in the PCR with pBB35 (12) as template. The PCR product was digested with BamHI and NsiI and cloned between the BamHI and PstI sites of pQE30.

To create pQE30ArcB521-778, H717Q the mutagenic primer 5'-GGCATTGTTGAGGAAGGACAGAAAATTAAAGGTGCGGCG-3' and primer 5'-CCCGGATCCATGCATCGCGCACCCCGGTCTAGCC-3' were used in the PCR with pBB25 (12) as template. The product of this reaction was purified and used as a megaprimer for PCR in combination with primer 5'-CCCGGATCCCATATGCCTTTACCGGCGCTGAATGTGC-3' and pBB25 as template. Finally, the product of the second PCR reaction was digested with BamHI and NsiI and cloned between the BamHI and PstI sites of pQE30.

All DNA fragments cloned from PCR-amplified material were verified by sequencing at Micro Core Facility of the Department of Microbiology and Molecular Genetics, Harvard Medical School.

Purification of His6-tagged Proteins, Isolation of His6-ArcA1-136-P, and Dephosphorylation Assays-- Expression and purification of the His6-tagged proteins were described previously (24). Phosphorylation of His6-ArcA1-136 (~0.4 nmol) was carried out at 25 °C in 20 µl of buffer A (33 mM HEPES at pH 7.5, 50 mM KCl, 5 mM MgCl2, 1 mM dithiothreitol, 0.1 mM EDTA, and 10% glycerol) containing His6-ArcB78-778 (~50 pmol) and 40 µM [gamma -32P]ATP (specific activity 2 Ci/mmol, NEN Life Science Products). After 10 min, the reaction was terminated by addition of 100 µl of buffer B (50 mM Tris-HCl at pH 7.0, 150 mM KCl, 5 mM EDTA, and 3% Triton X-100). His6-ArcB78-778 was separated from the reaction mixture by ultrafiltration, using a Nanosep 30K device (Pallfiltron). The filtrate, containing His6-ArcA1-136-P was passed through a Nanosep 10K device, and the retained material was washed 4 times with 500 µl of buffer B and once with 500 µl of buffer A to remove small molecules such as ATP and Pi. Finally, the retained material containing His6-ArcA1-136-P (essentially free of His6-ArcB78-778, nonhydrolyzed ATP and Pi) was diluted to a final volume of 200 µl with buffer A. Dephosphorylation reactions were carried out at 25 °C in mixtures of 35 µl of buffer A, containing ~50 pmol of His6-ArcA1-136-P and ~5 pmol of ArcB78-778 or its subdomain(s). At various time points, a 5-µl sample was withdrawn, mixed with 5 µl of SDS sample buffer, and kept on ice. One µl of each sample was analyzed for Pi by TLC in 2 N formic acid and 0.5 M LiCl for 45 min, using polyethyleneimine cellulose plates (Aldrich). The rest of the sample (9 µl) was analyzed for the proteins by SDS-PAGE on 15% polyacrylamide gels. The radioactivity of proteins or Pi resolved on SDS gels or TLC plates was determined qualitatively by autoradiography with X-Omat AR (Kodak) and quantitatively by a PhosphorImager (Molecular Dynamics).

    RESULTS
Top
Abstract
Introduction
Procedures
Results
Discussion
References

Effect of ArcB on the Dephosphorylation of ArcA-P-- To test whether ArcB catalyzes the dephosphorylation of ArcA-P, we carried out an exploratory experiment in which His6-ArcB78-778 (hereafter referred to as H1-D1-H2) and His6-ArcA (hereafter referred to as ArcA) were incubated with [gamma -32P]ATP.

An N-terminally truncated ArcB was used because the removal of the two transmembrane segments facilitated the purification of the protein which is constitutively active as an autokinase (24, 31). After 10 min of incubation, the reaction mixture was divided into 2 aliquots as follows: one served as the control and the other was fortified with additional H1-D1-H2 (Fig. 2). In the control reaction, the amount of ArcA-P continued to increase until it reached a steady state. By contrast, in the reaction mixture supplemented with H1-D1-H2, the amount of ArcA-P decreased rapidly. Furthermore, the level of phosphorylated H1-D1-H2 in the second reaction mixture increased transiently. This increase may reflect either the autophosphorylation of the added protein or its transphosphorylation by ArcA-P. The radioactivity lost from ArcA greatly exceeded that acquired by H1-D1-H2. The difference is essentially accounted for by the Pi liberated (not shown). The results suggest that ArcB catalyzes both the phosphorylation of ArcA and the dephosphorylation of ArcA-P.


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  		Fig. 2.   Acceleration of ArcA-P dephosphorylation by ArcB. ArcA (100 pmol) and H1-D1-H2 (10 pmol) were incubated with [gamma -32P]ATP (50 µmol) in a total reaction volume of 100 µl. After 10 min, the reaction mixture was divided into two equal portions (indicated by arrows): one served as control, and the other received 25 pmol of H1-D1-H2 (0.5 µl). At the indicated time intervals, 5 µl of the reaction mixtures were withdrawn for analysis of ArcA-P (top panel) and H1-D1-H2-P (bottom panel). Closed diamonds, ArcA-P in the control reaction; open diamonds, ArcA-P in the reaction fortified with H1-D1-H2; closed circles, H1-D1-H2-P in the control reaction mixture; open circles, H1-D1-H2-P in the reaction mixture fortified with H1-D1-H2.

Efforts to isolate ArcA-P for direct assays of its dephosphorylation were unsuccessful due to its tendency to aggregate during the purification process. Since a previous study showed that the response regulator NtrC, possessing only its N-terminal receiver domain, retained the activity as a substrate of the cognate sensor kinase (32), we used a similar approach to bypass our problem. His6-ArcA1-136 (hereafter referred to as ArcA'), containing the receiver domain but lacking the HTH (DNA binding) domain, was prepared. The purified ArcA' was indeed found to be an effective substrate for phosphorylation when incubated with H1-D1-H2 in the presence of [gamma -32P]ATP. The product, ArcA'-P, was separated from H1-D1-H2, ATP, and Pi and used as substrate for testing the phosphatase activity of ArcB or its subdomains. We used H1-D1-H2 and its modular derivatives to test the ArcA-P dephosphorylating activities, since in a previous study on signal transmission, these polypeptides were found to be catalytically active (24).

Spontaneous and Catalytic Dephosphorylation of ArcA'-P-- ArcA'-P was first tested for the intrinsic stability of its phospho-aspartyl bond. When incubated in buffer A (pH 7.5) at 25 °C, the half-life of the phospho-protein was found to exceed 1 h (Fig. 3A). Incubation of ArcA'-P with purified H1-D1-H2 resulted in a rapid release of Pi with concomitant loss of radiolabel from ArcA'-P. During the course of this reaction, there was a slight transient rise of labeled H1-D1-H2 followed by a gradual decay, suggesting that the phosphoryl group was transferred from ArcA'-P to H1-D1-H2 and subsequently to H2O (Fig. 3B).


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  		Fig. 3.   ArcA'-P dephosphorylating activity of ArcB and its subdomains. Purified ArcA'-P (50 pmol) was incubated with different ArcB domains (5 pmol) in a 35-µl reaction mixture. At the indicated time points, a 5-µl sample was withdrawn for SDS-PAGE and TLC analysis (see "Materials and Methods"). Polypeptides present in the reaction are indicated below each autoradiogram. The position of each polypeptide in the gel is indicated on the right side of each panel. A, ArcA'-P alone; B, ArcA'-P with H1-D1-H2; C, ArcA'-P with D1-H2; D, ArcA'-P with H1-D1; E, ArcA'-P with H1; F, ArcA'-P with D1; and G, ArcA'-P with H2. When useful, the normalized rates of phosphoryl group transfer and Pi release are presented graphically below the autoradiogram. Filled squares, ArcA'-P; open circles, Pi; and open diamonds, H1-D1-H2-P in the case of reaction B or D1-H2-P in the case of reaction C.

Attempts were then made to locate the dephosphorylating activity in H1-D1-H2 by the use of its various modular derivatives. The possibility of the phosphatase activity residing in H1 (His6-ArcB78-521) was first tested by incubating this domain with ArcA'-P. No dephosphorylating activity was detected (Fig. 3E). H1-D1 (His6-ArcB78-661) also had no effect on the stability of ArcA'-P (Fig. 3D). Moreover, neither H1 nor H1-D1 acquired the phosphoryl group from ArcA'-P at a detectable level. By contrast, D1-H2 (His6-ArcB521-778) catalyzed the hydrolysis of ArcA'-P at a rate similar to that by H1-D1-H2 and became transiently labeled itself (Fig. 3C). When D1 (His6-ArcB521-661) or H2 (His6-ArcB638-778) was tested separately, no ArcA'-P dephosphorylating activity was observed (Fig. 3, F and G). A mixture of the two proteins, however, did (Fig. 4A). The rate was equivalent to that catalyzed by the covalently linked D1-H2 (compare with Fig. 3C). Thus D1 and H2 each provides an essential catalytic function for the ArcA'-P dephosphorylation process. Because of the similarity in molecular weights of D1, H2, and ArcA', this experiment could not reveal whether or not D1 or H2 acquired the phosphoryl group from ArcA'-P.


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  		Fig. 4.   The roles of Asp-576 and His-717 of ArcB in ArcA'-P dephosphorylation. Purified ArcA'-P (50 pmol) was incubated with D1 and H2 or the mutant peptides in a 35-µl reaction mixture. At the indicated time points, a 5-µl sample was withdrawn for SDS-PAGE and TLC analysis and subsequent quantitation by the PhosphorImager (see "Materials and Methods"). A, ArcA'-P incubated with D1 and H2; B, ArcA'-P incubated with D1D576A and H2; C, ArcA'-P incubated with D1 and H2H717Q. Top, autoradiogram of the protein band in the gel. Bottom, the rate of ArcA'-P dephosphorylation graphically presented as relative amount of labeled protein or Pi versus time. Filled squares, ArcA'-P; open circles, Pi.

Dephosphorylation of ArcA'-P by a Reverse Phosphorelay-- To probe whether both His-717 of H2 and Asp-576 of D1 are critical in the concerted process of ArcA'-P dephosphorylation, a mixture of D1D576A and H2 or a mixture of D1 and H2H717Q was tested. Neither exhibited any significant phosphatase activity (Fig. 4, B and C). To answer the question of whether the order of phospho-transfer was from ArcA'-P to H2 and then to D1, mutant D1-H2 proteins were used, since they could be separated from ArcA'-P. When ArcA'-P was incubated with D1D576A-H2, the phosphoryl group was transferred to the mutant protein, and the radiolabel lost from ArcA'-P was accounted for by the radiolabel gained by D1D576A-H2. By contrast, when ArcA'-P was incubated with D1-H2H717Q, the mutant protein did not receive any phosphoryl group. As expected, neither mutant protein catalyzed the release of Pi (Fig. 5). It thus appears that ArcA'-P dephosphorylation proceeds in the reverse direction of the His right-arrow Asp right-arrow His right-arrow Asp phosphorelay (24), except that H1 is dispensable.


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  		Fig. 5.   Effects of D1D576A-H2 and D1-H2H717Q on the ArcA'-P dephosphorylation. Purified ArcA'-P (50 pmol) was incubated with D1D576A-H2 or D1-H2H717Q (5 pmol) in a 35-µl reaction mixture. At the indicated time points, a 5-µl sample was withdrawn for SDS-PAGE and TLC analysis and subsequent quantitation by the PhosphorImager (see "Materials and Methods"). A, ArcA'-P incubated with D1D576A-H2; B, ArcA'-P incubated with D1-H2H717Q. Top panel shows the autoradiogram of the protein bands. Bottom panel shows the rate of ArcA'-P dephosphorylation graphically presented as relative amount of labeled protein versus time. Filled squares, ArcA'-P; open diamonds, D1D576A-H2-P or D1-H2H717Q-P.

Possible Effectors in the Signal Decay Pathway-- It has been reported that ATP or its nonhydrolyzable analogs accelerate the dephosphorylation of the response regulators by their orthodox cognate sensors, namely NtrB (32, 33), EnvZ (34, 35), and DegS (36). We therefore tested the effects of ATP, ADP, AMP-PMP, ATPgamma S, and GTP on the dephosphorylation of ArcA'-P by H1-D1-H2. No significant effect was observed (data not shown). In a previous study on ArcB128-778, physiological concentrations (mM range) of D-lactate, acetate, or pyruvate were found to accelerate the rate of autophosphorylation, heighten the peak phosphorylation level, and slightly retard the rate of Pi loss from the kinase protein. Because the intracellular levels of these compounds were known to be elevated during anoxia, it was suggested that they serve as input signals by retarding the autophosphatase activity of ArcB (37). When we tested the influence of those metabolites on the ArcA'-P dephosphorylating activity of H1-D1-H2 and D1-H2, none of them showed any significant effect on either the rate of ArcA'-P decay or Pi release (data not shown). Preliminary experiments indicated that these effectors act on the kinase phosphorelay pathway.2

    DISCUSSION
Top
Abstract
Introduction
Procedures
Results
Discussion
References

Several modes for signal decay seem to have evolved for the two-component systems. The rate of dephosphorylation of a response regulator appears to be controlled by the inherent lability of the mixed anhydride phospho-aspartyl bond and/or a phosphatase-like activity embodied in the cognate sensor kinase or another protein. The rate of spontaneous hydrolysis may be intrinsically set by the protein structure, since the half-life of the phospho-response regulators vary from seconds to hours (Ref. 38 and references therein).

Examples of catalyzed dephosphorylation of phospho-response regulators include those that are sensor kinase-dependent, such as the EnvZ/OmpR (35, 39), NarX/NarL (40, 41), and CpxA/R (42) systems of E. coli; the DegS/U system of B. subtilis (36, 43); the VanS/R system of Enterococcus faecium (44), and the FixL/J system of Rhizobium meliloti (45). Mutational analyses have shown that the conserved histidine of the sensor kinases EnvZ (46, 47), CpxA (42), and VanS (38) is not essential for the dephosphorylating activity.

Another class of phospho-response regulator dephosphorylations involve a third protein. Examples include the Ntr and Che systems of E. coli and the Kin/Spo phosphorelay system of B. subtilis. The dephosphorylation of NtrC-P by NtrB is controlled by the protein PII (33, 48), whereas the dephosphorylation of CheY-P is accelerated by CheZ (49-51). In the Kin/Spo system (52), the dephosphorylation of SpoOA-P (the terminal receiver domain) is catalyzed by SpoOE (53), and the dephosphorylation of SpoOF-P (the intermediate receiver domain) is catalyzed by a family of Rap (response regulator aspartate phosphatases) proteins (54-56). From the mechanistic point of view, the dephosphorylation by sensor kinases or other proteins may involve either their direct participation in the hydrolytic reaction or their allosteric binding to the cognate phospho-response regulator, resulting in destabilization of the phosphoryl bond (50, 57). Future studies will be required to resolve this issue.

Yet another mode of signal decay emerged from our in vitro study on ArcA-P dephosphorylation by the ArcB tripartite kinase: Pi release through a reverse phosphorelay (Fig. 6). The relatively long half-life of ArcA-P (>1 h) seems to render its spontaneous hydrolysis as an insignificant factor in signal decay. Instead, before the phosphoryl group is hydrolyzed, it needs to be transferred from ArcA-P to H2 at the conserved His-717 and subsequently to the conserved Asp-576 of D1. This conclusion is supported by in vivo studies involving plasmid-borne wild-type or mutant ArcB domains.3 However, the possibility of additional dephosphorylation pathways catalyzed by unknown proteins cannot be excluded.


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  		Fig. 6.   A model for signal transduction by the Arc system with special focus on the reactions leading to the phosphorylation and dephosphorylation of the response regulator, ArcA. Arrows indicate the directions of phosphoryl group transfer with the thickness of the arrows indicating the relative activities of these reactions observed under in vitro conditions.

It is noteworthy that H1, the classical transmitter domain, plays no apparent role in the dephosphorylation process of ArcA-P. Despite the previous observation that H1 transphosphorylated ArcA at a relatively low rate (24), it is unable to accept a detectable amount of the phosphoryl group from ArcA-P, possibly because of an unfavorable equilibrium constant. It was originally suggested that the primary transmitter of ArcB serves as the direct phosphoryl group donor for ArcA (12) and that the secondary transmitter is involved in cross-talk with a hypothetical response regulator(s) (13, 15). However, subsequent studies showed that in vitro H2 is more effective than H1 in transphosphorylating ArcA (24) and that in vivo both may serve as phosphoryl group donors, depending on the regulatory inputs (58). A recent study of BvgA/S and EvgA/S demonstrated that the specificity of the phosphorelay is mediated by the secondary, rather than the primary, transmitter domain (28). Recently, a sixA (signal inhibitory factor-X) gene was discovered to encode a phosphatase that is active on the His-717-P of ArcBH292L, D576Q but not on the His-273-P of an N-terminally truncated version of EnvZ (59). A specific physiological role of SixA on the Arc signal transduction system, however, remains to be shown.

In the BvgS/A system, the phosphorylated receiver domain of BvgS has been shown to reversibly transphosphorylate the secondary transmitter or to undergo spontaneous hydrolysis (60). Although not demonstrated, the dephosphorylation of BvgA-P is likely to occur through a reverse phosphorelay (Asp right-arrow His right-arrow Asp), as in the case of ArcA-P. Indeed, such a multi-step dephosphorylation pathway may apply to all two-component systems comprising a tripartite sensor kinase.

An advantage of a multi-step phosphorelay network may be the availability of different rate control points for signaling, as illustrated by the Kin/Spo system (52-56). In the Arc system, it has been suggested that the ArcB autophosphatase activity is regulated at the receiver domain by several fermentative metabolites, such as D-lactate (37). The present study with modular ArcB units, however, failed to confirm any inhibiting effect of D-lactate on the various steps of ArcA-P dephosphorylation. In any event, the receiver domain seems to play a pivotal role in directing the phosphoryl group reversibly to His-717 or irreversibly to H2O. A challenge therefore remains to pinpoint the action of the effectors and to determine whether there are additional elements that influence signal transmission and signal decay.

    FOOTNOTES

* This work was supported in part by U. S. Public Health Service Grants GM40993 and GM30693 from the NIGMS of the National Institutes of Health.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Dagger Supported by Fellowship B-PD 11474-301 from the Swedish Natural Science Research Council.

§ To whom correspondence should be addressed: Dept. of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Ave., Boston, MA 02115. Tel.: 617-432-1925; Fax: 617-738-7664; E-mail: elin{at}hms.harvard.edu.

The abbreviations used are: PCR, polymerase chain reaction; PAGE, polyacrylamide gel electrophoresis; AMP-PMP, adenylyl-imidodiphosphate; ATPgamma S, adenosine 5'-O-[thiotriphosphate].

2 D. Georgellis, unpublished data.

3 D. Georgellis and O. Kwon, unpublished data.

    REFERENCES
Top
Abstract
Introduction
Procedures
Results
Discussion
References

  1. Hoch, J. A., and Silhavy, T. J. (eds) (1995) Two-component Signal Transduction, American Society for Microbiology, Washington, D. C.
  2. Rudolph, J., and Oesterhelt, D. (1995) EMBO J. 14, 667-673[Medline] [Order article via Infotrieve]
  3. Klenk, A.-P., Clayton, R. A., Tomb, J.-F., White, O., Nelson, K. E., Ketchum, K. A., Dodson, R. J., Gwinn, M., Hickey, E. K., Peterson, J. D., et al.. (1997) Nature 290, 364-370
  4. Ota, I. M., and Varshavsky, A. (1993) Science 262, 566-569
  5. Maeda, T., Wurgler-Murphy, S. M., and Saito, H. (1994) Nature 369, 242-245[CrossRef][Medline] [Order article via Infotrieve]
  6. Alex, L. A., Borkovich, K. A., and Simon, M. I. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 3416-3421[Abstract/Free Full Text]
  7. Chang, C., Kwok, S. F., Bleeker, A. B., and Meyerowitz, E. M. (1993) Science 262, 539-544
  8. Hua, J., Chang, C., Sun, Q., and Meyerowitz, E. M. (1995) Science 269, 1712-1714
  9. Chang, C. (1996) Trends Biochem. Sci. 21, 129-133[CrossRef][Medline] [Order article via Infotrieve]
  10. Iuchi, S., and Lin, E. C. C. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 1888-1892
  11. Lynch, A. S., and Lin, E. C. C. (1996) in Escherichia coli and Salmonella: Cellular and Molecular Biology (Neidhardt, F. C., Curtiss, R., III, Ingraham, J. L., Lin, E. C. C., Low, K. B., Magasanik, B., Reznikoff, W. S., Riley, M., Schaechter, M., and Umbarger, H. E., eds), 2nd Ed., pp. 1526-1538, American Society for Microbiology, Washington, D. C.
  12. Iuchi, S., and Lin, E. C. C. (1992) J. Bacteriol. 174, 3972-3980[Abstract/Free Full Text]
  13. Tsuzuki, M., Ishege, K., and Mizuno, T. (1995) Mol. Microbiol. 18, 953-962[CrossRef][Medline] [Order article via Infotrieve]
  14. Parkinson, J. S., and Kofoid, E. C. (1992) Annu. Rev. Genet. 26, 71-112
  15. Ishige, K., Nagasawa, S., Tokishita, S.-I., and Mizuno, T. (1994) EMBO J. 13, 5195-5202[Medline] [Order article via Infotrieve]
  16. Kato, M., Mizuno, T., Shimizu, T., and Hakoshima, T. (1997) Cell 88, 717-723[CrossRef][Medline] [Order article via Infotrieve]
  17. Mizuno, T. (1997) DNA Res. 4, 161-168[Abstract]
  18. Nagasawa, S., Tokishita, S., Aiba, H., and Mizuno, T. (1992) Mol. Microbiol. 6, 799-807[Medline] [Order article via Infotrieve]
  19. Arico, B., Miller, J. F., Roy, C., Stibitz, S., Monack, D., Falkow, S., Gross, R., and Rappuoli, R. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 6671-6675
  20. Utsumi, R., Katayama, S., Taniguchi, M., Horie, T., Ikeda, M., Igaki, S., Nakagawa, H., Miwa, A., Tanabe, H., and Noda, M. (1994) Gene (Amst.) 140, 73-77[CrossRef][Medline] [Order article via Infotrieve]
  21. Hrabak, E. M., and Willis, D. K. (1992) J. Bacteriol. 174, 3011-3020[Abstract/Free Full Text]
  22. Stevens, A. M., Sanders, J. M., Shoemaker, N. B., and Salyers, A. A. (1992) J. Bacteriol. 174, 2935-2942[Abstract/Free Full Text]
  23. Jourlin, C., Bengrine, A., Chippaux, M., and Méjean, V. (1996) Mol. Microbiol. 20, 1297-1306[CrossRef][Medline] [Order article via Infotrieve]
  24. Georgellis, D., Lynch, A. S., and Lin, E. C. C. (1997) J. Bacteriol. 179, 5429-5435[Abstract/Free Full Text]
  25. Burbulys, D., Trach, K. A., and Hoch, J. A. (1991) Cell 64, 545-552[CrossRef][Medline] [Order article via Infotrieve]
  26. Posas, F., Wurgler-Murphy, S. M., Maeda, T., Witten, E. A., Thai, T. C., and Saito, H. (1996) Cell 86, 865-875[CrossRef][Medline] [Order article via Infotrieve]
  27. Uhl, M. A., and Miller, J. F. (1996) EMBO J. 15, 1028-1036[Medline] [Order article via Infotrieve]
  28. Perraud, A.-L., Kimmel, B., Weiss, V., and Gross, R. (1998) Mol. Microbiol. 27, 875-887[CrossRef][Medline] [Order article via Infotrieve]
  29. Jourlin, C., Ansaldi, M., and Méjean, V. (1997) J. Mol. Biol. 267, 770-777[CrossRef][Medline] [Order article via Infotrieve]
  30. Lynch, A. S., and Lin, E. C. C. (1996) J. Bacteriol. 178, 6238-6249[Abstract/Free Full Text]
  31. Iuchi, S., and Lin, E. C. C. (1992) J. Bacteriol. 174, 5617-5623[Abstract/Free Full Text]
  32. Keener, J., and Kustu, S. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 4976-4980
  33. Ninfa, A. J., and Magasanik, B. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 5909-5913
  34. Aiba, H., Mizuno, T., and Mizushima, S. (1989) J. Biol. Chem. 264, 8563-8567[Abstract/Free Full Text]
  35. Igo, M. M., Ninfa, A. J., Stock, J. B., and Silhavy, T. J. (1989) Genes Dev. 3, 1725-1734[Abstract/Free Full Text]
  36. Dahl, M. K., Msadek, T., Kunst, F., and Rapoport, G. (1992) J. Biol. Chem. 267, 14509-14514[Abstract/Free Full Text]
  37. Iuchi, S. (1993) J. Biol. Chem. 268, 23972-23980[Abstract/Free Full Text]
  38. Wright, G. D., Holman, T. R., and Walsh, C. T. (1993) Biochemistry 32, 5057-5063[CrossRef][Medline] [Order article via Infotrieve]
  39. Aiba, H., Nakasai, F., Mizushima, S., and Mizuno, T. (1989) J. Biol. Chem. 264, 14090-14094[Abstract/Free Full Text]
  40. Walker, M. S., and DeMoss, J. A. (1993) J. Biol. Chem. 268, 8391-8393[Abstract/Free Full Text]
  41. Schröder, I., Wolin, C. D., Cavicchioli, R., and Gunsalus, R. (1994) J. Bacteriol. 176, 4985-4992[Abstract/Free Full Text]
  42. Raivio, T. L., and Silhavy, T. J. (1997) J. Bacteriol. 179, 7724-7733[Abstract/Free Full Text]
  43. Tanaka, T., Kawata, M., and Mukai, K. (1991) J. Bacteriol. 173, 5507-5515
  44. Haldimann, A., Fisher, S. L., Daniels, L. L., Walsh, C. T., and Wanner, B. L. (1997) J. Bacteriol. 179, 5903-5913[Abstract/Free Full Text]
  45. Lois, A. F., Weinstein, M., Ditta, G. S., and Helinski, D. (1993) J. Biol. Chem. 268, 4370-4375[Abstract/Free Full Text]
  46. Skarphol, K., Waukau, J., and Forst, S. A. (1997) J. Bacteriol. 179, 1413-1416[Abstract/Free Full Text]
  47. Hsing, W., and Silhavy, T. J. (1997) J. Bacteriol. 179, 3729-3735[Abstract/Free Full Text]
  48. Magasanik, B. (1996) in Regulation of Gene Expression in Escherichia coli (Lin, E. C. C., and Lynch, A. S., eds), pp. 281-287, R. G. Landes Co., Austin, TX
  49. Hess, J. F., Oosawa, K., Kaplan, N., and Simon, M. I. (1988) Cell 53, 79-87[CrossRef][Medline] [Order article via Infotrieve]
  50. Sanna, M. G., Swanson, R. V., Bourret, R. B., and Simon, M. I. (1995) Mol. Microbiol. 15, 1069-1079[Medline] [Order article via Infotrieve]
  51. Bren, A., Welch, M., Blat, Y., and Eisenbach, M. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 10090-10093[Abstract/Free Full Text]
  52. Perego, M., Glaser, P., and Hoch, J. A. (1996) Mol. Microbiol. 19, 1151-1157[Medline] [Order article via Infotrieve]
  53. Ohlsen, K. L., Grimsley, J. K., and Hoch, J. A. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 1756-1760[Abstract/Free Full Text]
  54. Perego, M., Hanstein, C., Welsh, K. M., Djavakhishvili, T., Glaser, P., and Hoch, J. A. (1994) Cell 79, 1047-1055[CrossRef][Medline] [Order article via Infotrieve]
  55. Perego, M., and Hoch, J. A. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 1549-1553[Abstract/Free Full Text]
  56. Perego, M. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 8612-8617[Abstract/Free Full Text]
  57. Stock, J. B., Surette, M. G., Levit, M., and Park, P. (1995) in Two-component Signal Transduction (Hoch, J. A., and Silhavy, T. J., eds), pp. 25-52, American Society for Microbiology, Washington, D. C.
  58. Matsushika, A., and Mizuno, T. (1998) J. Bacteriol. 180, 3973-3977[Abstract/Free Full Text]
  59. Ogina, T., Matsubara, M., Kato, N., Nakamura, Y., and Mizuno, T. (1998) Mol. Microbiol. 27, 573-585[CrossRef][Medline] [Order article via Infotrieve]
  60. Uhl, M. A., and Miller, J. F. (1996) J. Biol. Chem. 271, 33176-33180[Abstract/Free Full Text]
  61. Iuchi, S., Matsuda, Z., Fujiwara, T., and Lin, E. C. C. (1990) Mol. Microbiol. 4, 715-727[CrossRef][Medline] [Order article via Infotrieve]
  62. Boyd, D., Traxler, B., and Beckwith, J. (1993) J. Bacteriol. 175, 553-556[Abstract/Free Full Text]
  63. Landschulz, W. H., Johnson, P. F., and McKnight, S. L. (1988) Science 240, 1759-1764
  64. Parkinson, J. S. (1995) in Two-component Signal Transduction (Hoch, J. A., and Silhavy, T. J., eds), pp. 9-24, American Society for Microbiology, Washington, D. C.
  65. Iuchi, S., and Lin, E. C. C. (1995) in Two-component Signal Transduction (Hoch, J. A., and Silhavy, T. J., eds), pp. 223-232, American Society for Microbiology, Washington, D. C.

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