Helicobacter pylori chemoreceptor TlpC mediates chemotaxis to lactate

Machuca, Mayra A.; Johnson, Kevin S.; Liu, Yu C.; Steer, David; Ottemann, Karen M.; Roujeinikova, Anna

doi:10.1038/s41598-017-14372-2

Cited by 59 publications

(67 citation statements)

References 106 publications

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“…Although CAD2 shows a fold similar to that of CAD1, the ligands bind only to CAD1 ( Fig. 2B to G), like other known dCACHE-type chemoreceptors except for TlpC (10)(11)(12)(13).…”

Section: Resultsmentioning

confidence: 84%

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

et al. 2019

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Bacteria sense environmental chemicals using chemosensor proteins, most of which are present in the cytoplasmic membrane. Canonical chemoreceptors bind their specific ligands in their periplasmic domain, and the ligand binding creates a molecular stimulus that is transmitted into the cytoplasm, leading to various cellular responses, such as chemotaxis and specific gene expression. Vibrio cholerae, the causative agent of cholera, contains about 44 putative sensor proteins, which are homologous to methyl-accepting chemotaxis proteins involved in chemotaxis. Two of them, Mlp24 and Mlp37, have been identified as chemoreceptors that mediate chemotactic responses to various amino acids. Although most of the residues of Mlp37 involved in ligand binding are conserved in Mlp24, these chemoreceptors bind the same ligands with different affinities. Moreover, they have distinct cellular roles. Here we determined a series of ligand complex structures of the periplasmic domains of Mlp24 (Mlp24p). The structures revealed that Ca 2ϩ binds to the loop that forms the upper wall of the ligand-binding pocket. Ca 2ϩ does not bind to the corresponding loop of Mlp37, implying that the structural difference of the loop may cause the ligand affinity difference. Isothermal titration calorimetry (ITC) measurements indicated that Ca 2ϩ changes the ligand binding affinity of Mlp24p. Furthermore, Ca 2ϩ affected chemotactic behaviors to various amino acids mediated by Mlp24. Thus, Ca 2ϩ is suggested to serve as a cosignal for the primary signal mediated by Mlp24p, and V. cholerae fine-tunes its chemotactic behavior depending on the Ca 2ϩ concentration by modulating the ligand sensitivity of Mlp24. IMPORTANCE Mlp24 and Mlp37 are homologous chemoreceptors of Vibrio cholerae that bind various amino acids. Although most of the residues involved in ligand interaction are conserved, these chemoreceptors show different affinities for the same ligand and play different cellular roles. A series of ligand complex structures of the periplasmic region of Mlp24 (Mlp24p) and following ITC analysis revealed that Ca 2ϩ binds to the loop of Mlp24p and modulates the ligand binding affinity of Mlp24p. Moreover, Ca 2ϩ changes the chemotactic behaviors mediated by Mlp24. We propose that Ca 2ϩ acts as a cosignal that modulates the affinity of Mlp24 for the primary signal, thereby changing the chemotactic behavior of V. cholerae.

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“…Although CAD2 shows a fold similar to that of CAD1, the ligands bind only to CAD1 ( Fig. 2B to G), like other known dCACHE-type chemoreceptors except for TlpC (10)(11)(12)(13).…”

Section: Resultsmentioning

confidence: 84%

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

et al. 2019

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“…Scale bar is 5 µm. TM1 (TlpC‐TM 1 domain), TM2 (TlpC‐TM 2 domain), d1 (dCACH_1 domain), H1 (HAMP1 domain), H2 (HAMP2 domain), MACP (methyl‐accepting chemotaxis like domain) (Machuca et al ., ). B.…”

Section: Resultsmentioning

confidence: 97%

The Helicobacter pylori cell shape promoting protein Csd5 interacts with the cell wall, MurF, and the bacterial cytoskeleton

Blair

Mears

Taylor

et al. 2018

Molecular Microbiology

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Chronic infection with Helicobacter pylori can lead to the development of gastric ulcers and stomach cancers. The helical cell shape of H. pylori promotes stomach colonization. Screens for loss of helical shape have identified several periplasmic peptidoglycan (PG) hydrolases and non-enzymatic putative scaffolding proteins, including Csd5. Both over and under expression of the PG hydrolases perturb helical shape, but the mechanism used to coordinate and localize their enzymatic activities is not known. Using immunoprecipitation and mass spectrometry we identified Csd5 interactions with cytosolic proteins CcmA, a bactofilin required for helical shape, and MurF, a PG precursor synthase, as well as the inner membrane spanning ATP synthase. A combination of Csd5 domain deletions, point mutations, and transmembrane domain chimeras revealed that the N-terminal transmembrane domain promotes MurF, CcmA, and ATP synthase interactions, while the C-terminal SH3 domain mediates PG binding. We conclude that Csd5 promotes helical shape as part of a membrane associated, multi-protein shape complex that includes interactions with the periplasmic cell wall, a PG precursor synthesis enzyme, the bacterial cytoskeleton, and ATP synthase.

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“…The chemotaxis machinery of Helicobacter pylori has been comprehensively studied due to the early recognition that H. pylori relies on chemotaxis for colonization of gastric mucosa (Foynes et al, 2000;Andermann et al, 2002), which leads to the stomach infection and inflammation of the gastric epithelial tissue (Croxen et al, 2006;Williams et al, 2007;Rolig et al, 2012;Huang et al, 2015). Although all four MCPs (TlpA-TlpD) of H. pylori have been experimentally characterized (see Table S3), this bacterium exhibits chemotactic responses to various amino acids and bile acids, which have not yet been assigned to any of these chemoreceptors (Machuca et al, 2017). There is also some understanding of the functions of the H. pylori's HKs (Waidner et al, 2005;Joseph and Beier, 2007;Marcus et al, 2012;Tsang et al, 2015) but not of its Ser/Thr/Tyr protein kinase and phosphatase.…”

mentioning

confidence: 99%

What bacteria want

Galperin

2018

Environmental Microbiology

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Bacterial signal transduction systems are responsible for sensing environmental cues and adjusting the cellular behaviour and/or metabolism in response to these cues. They also monitor the intracellular conditions and the status of the cell envelope and the cytoplasmic membrane and trigger various stress responses to counteract adverse changes. This surveillance involves several classes of sensor proteins: histidine kinases; chemoreceptors; membrane components of the sugar phosphotransferase system; adenylate, diadenylate and diguanylate cyclases and certain cAMP, c-di-AMP and c-di-GMP phosphodiesterases; extracytoplasmic function sigma factors and Ser/Thr/Tyr protein kinases and phosphoprotein phosphatases. We have compiled a detailed listing of sensor proteins that are encoded in the genomes of Escherichia coli, Bacillus subtilis and 10 widespread pathogens: Chlamydia trachomatis, Haemophilus influenzae, Helicobacter pylori, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Porphyromonas gingivalis, Rickettsia typhi, Streptococcus pyogenes and Treponema pallidum, and checked what, if anything, is known about their functions. This listing shows significant gaps in the understanding of which environmental and intracellular cues are perceived by these bacteria and which cellular responses are triggered by the changes in the respective parameters. A better understanding of bacterial preferences may suggest new ways to modulate the expression of virulence factors and therefore decrease the reliance on antibiotics to fight infection.

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Helicobacter pylori chemoreceptor TlpC mediates chemotaxis to lactate

Cited by 59 publications

References 106 publications

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

Calcium Ions Modulate Amino Acid Sensing of the Chemoreceptor Mlp24 of Vibrio cholerae

The Helicobacter pylori cell shape promoting protein Csd5 interacts with the cell wall, MurF, and the bacterial cytoskeleton

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