Rapid attractant-induced changes in methylation of methyl-accepting chemotaxis proteins in Bacillus subtilis

Thoelke, Mark; Parker, Helen M.; Ordal, Erik A.; Ordal, George

doi:10.1021/bi00422a024

Cited by 31 publications

(34 citation statements)

References 18 publications

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“…Cells of the gram-positive bacterium Bacillus subtilis have a unique chemotactic mechanism for sensing the environment and migrating to more-favorable conditions (20,21,31,32,34). Methyl groups are apparently transferred from methyl-accepting chemotactic proteins (MCPs) to an intermediate carrier or regulator (31)(32)(33)(34) throughout the adaptation period.…”

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Bacillus subtilis CheN, a homolog of CheA, the central regulator of chemotaxis in Escherichia coli

Führer

Ordal

1991

J Bacteriol

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The Bacilus subtilis cheN gene was isolated, sequenced, and expressed. It encodes a large negatively charged protein with a molecular weight of approximately 74,000. The predicted protein sequence has 33 to 34% identity with the Escherichia coli and SalmoneUla typhimunium CheA and Myxococcus xanthus FrzE sequences. These proteins are found to autophosphorylate and are members of the same histidine kinase signal modulating family.CheN has several conserved regions (including the histidine that is phosphorylated in CheA) that coincide with other autophosphorylated signal transducers. A null mutant is defective in attractant-induced methanol formation and shows no behavioral response to chemoeffectors. These results imply that in B. subtilis the mechanism of chemotaxis involves phosphoryl transfer similar to that in E. coli. However, the CheN null mutant mostly tumbles, whereas CheA mutants swim smoothly, and only in B. subtilis does excitation lead to methyl transfer and methanol formation. Thus, the overall mechanism of chemotaxis is different in the two organisms.

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confidence: 99%

Bacillus subtilis CheN, a homolog of CheA, the central regulator of chemotaxis in Escherichia coli

Führer

Ordal

1991

J Bacteriol

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“…We have reported previously that the mechanism of chemotaxis in Bacillus subtilis is different in some respects from that observed in E. coli and S. typhimurium; the differences appear to be in the role that methyl transfer plays in excitation and adaptation (33)(34)(35). To characterize these differences further, we have been isolating and studying chemotaxis mutants (28,29).…”

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Nucleotide sequence and characterization of a Bacillus subtilis gene encoding a flagellar switch protein

1991

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The nucleotide sequence of the Bacillus subtilisfliM gene has been determined. This gene encodes a 38-kDa protein that is homologous to the FliM flagellar switch proteins of Escherichia coli and SalmoneUa typhimurium. gene cannot complement an E. colifliM mutant. A frameshift mutation was constructed in thefJl gene, and the mutation was transferred onto the B. subtilis chromosome. The mutant has a Fla-phenotype. This phenotype is consistent with the hypothesis that the FliM protein encodes a component of the flagellar switch in B. subtilis. Additional characterization of the fliM mutant suggests that the hag and mot loci are not expressed. These loci are regulated by the SigD form of RNA polymerase. We also did not observe any methyl-accepting chemotaxis proteins in an in vivo methylation experiment. The expression of these proteins is also dependent upon SigD. It is possible that a functional basal body-hook complex may be required for the expression of SigD-regulated chemotaxis and motility genes.

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“…On the basis of other data, we speculate that methyl groups are transferred to a regulator protein (4). The cytosolic concentration of this methylated regulator would increase with addition of attractant (32)(33)(34) 174,1992 …”

Section: Discussionmentioning

confidence: 90%

“…Unlike for E. coli (13), there is little change in MCP methylation with chemotactic stimulation for B. subtilis (32,34 CheA, which controls the behavior of the cell (6,7,16,21). To determine whether the B. subtilis cheW mutant was sensitive to the addition of attractant, the null mutant and the corresponding wild-type strains were exposed to a high concentration of a strong attractant (0.1 M aspartate) (25) under cold chase conditions.…”

Section: Resultsmentioning

confidence: 99%

“…These methyl groups remain in the system, rather than evolving directly as methanol, since they return to the MCPs (32-34) when the attractant is removed. It is believed that these methyl groups are transferred to a regulator protein, but its function is not presently understood (2,(31)(32)(33)(34). Another significant comparison between E. coli and B. subtilis is the switch that controls the direction of flagellar rotation.…”

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Influence of attractants and repellents on methyl group turnover on methyl-accepting chemotaxis proteins of Bacillus subtilis and role of CheW

1992

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The ability of attractants and repellents to affect the turnover of methyl groups on the methyl-accepting chemotaxis proteins (MCPs) was examined for Bacillus subtilis. Attractants were found to cause an increase in the turnover of methyl groups esterified to the MCPs, while repellents caused a decrease. These reactions do not require CheW. However, a cheW null mutant exhibits enhanced turnover in unstimulated cells. Assuming that the turnover of methyl groups on the MCPs reflects a change in the activity of CheA, these results suggest that the activation of CheA via chemoeffector binding at the receptor does not require CheW.Escherichia coli has been the prototype for understanding chemotactic sensory transduction in bacteria. In E. coli, when a chemoeffector binds to the receptors, or methylaccepting chemotaxis proteins (MCPs), a conformational change occurs in the receptor, which transmits the information from the periplasmic space to the cytoplasm (30). The addition of attractant in the presence of CheW is believed to inhibit the autophosphorylation of CheA such that the level of CheY-P subsequently decreases (7,21). CheY-P is thought to bind to the switch to cause clockwise rotation of the flagella (20,23,27,28,36,37). The addition of attractant also increases the rate of methylation of the MCPs by the methyltransferase (13) CheR such that the rate of CheA autophosphorylation can return to normal (29), thus allowing the bacteria to adapt. Repellents are believed to increase the rate of autophosphorylation of CheA and hence the level of CheY-P (6), inducing the bacteria to tumble. However, CheA-P also phosphorylates CheB, and CheB-P, which is the activated form of the methylesterase (17), rapidly demethylates the MCPs so that CheA-P returns to the prestimulus level (20).Chemotaxis in Bacillus subtilis has significant similarities to as well as differences from chemotaxis in E. coli. For instance, B. subtilis has homologs to CheA (10), CheB (11,19), CheR (8, 9), CheW (14), and CheY (3). CheA in B. subtilis, like that in E. coli, is probably the master controller of chemotaxis, because excitation does not occur in a cheA null mutant (10). However, a novel reaction, whereby attractants cause a high rate of turnover of methyl groups on the MCPs, occurs in B. subtilis. These methyl groups remain in the system, rather than evolving directly as methanol, since they return to the MCPs (32-34) when the attractant is removed. It is believed that these methyl groups are transferred to a regulator protein, but its function is not presently understood (2, 31-34). Another significant comparison between E. coli and B. subtilis is the switch that controls the direction of flagellar rotation. Both organisms have FliM (38) and FliG (1) homologs. In addition, E. coli has a small (14-kDa) protein, FliN (15,18)

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Rapid attractant-induced changes in methylation of methyl-accepting chemotaxis proteins in Bacillus subtilis

Cited by 31 publications

References 18 publications

Bacillus subtilis CheN, a homolog of CheA, the central regulator of chemotaxis in Escherichia coli

Bacillus subtilis CheN, a homolog of CheA, the central regulator of chemotaxis in Escherichia coli

Nucleotide sequence and characterization of a Bacillus subtilis gene encoding a flagellar switch protein

Influence of attractants and repellents on methyl group turnover on methyl-accepting chemotaxis proteins of Bacillus subtilis and role of CheW

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