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The domain architecture of PtkA, the first tyrosine kinase from Mycobacterium tuberculosis, differs from the conventional kinase architecture.

ABSTRACT: The discovery that MptpA (low-molecular-weight protein tyrosine phosphatase A) from Mycobacterium tuberculosis (Mtb) has an essential role for Mtb virulence has motivated research of tyrosine-specific phosphorylation in Mtb and other pathogenic bacteria. The phosphatase activity of MptpA is regulated via phosphorylation on Tyr128 and Tyr129 Thus far, only a single tyrosine-specific kinase, protein-tyrosine kinase A (PtkA), encoded by the Rv2232 gene has been identified within the Mtb genome. MptpA undergoes phosphorylation by PtkA. PtkA is an atypical bacterial tyrosine kinase, as its sequence differs from the sequence consensus within this family. The lack of structural information on PtkA hampers the detailed characterization of the MptpA-PtkA interaction. Here, using NMR spectroscopy, we provide a detailed structural characterization of the PtkA architecture and describe its intra- and intermolecular interactions with MptpA. We found that PtkA's domain architecture differs from the conventional kinase architecture and is composed of two domains, the N-terminal highly flexible intrinsically disordered domain (IDDPtkA) and the C-terminal rigid kinase core domain (KCDPtkA). The interaction between the two domains, together with the structural model of the complex proposed in this study, reveal that the IDDPtkA is unstructured and highly dynamic, allowing for a "fly-casting-like" mechanism of transient interactions with the rigid KCDPtkA This interaction modulates the accessibility of the KCDPtkA active site. In general, the structural and functional knowledge of PtkA gained in this study is crucial for understanding the MptpA-PtkA interactions, the catalytic mechanism, and the role of the kinase-phosphatase regulatory system in Mtb virulence.

SUBMITTER: Niesteruk A

PROVIDER: S-EPMC6066317 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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The domain architecture of PtkA, the first tyrosine kinase from Mycobacterium tuberculosis, differs from the conventional kinase architecture.

Niesteruk Anna A Jonker Hendrik R A HRA Richter Christian C Linhard Verena V Sreeramulu Sridhar S Schwalbe Harald H

The Journal of biological chemistry 20180608 30

The discovery that MptpA (low-molecular-weight protein tyrosine phosphatase A) from Mycobacterium tuberculosis (Mtb) has an essential role for Mtb virulence has motivated research of tyrosine-specific phosphorylation in Mtb and other pathogenic bacteria. The phosphatase activity of MptpA is regulated via phosphorylation on Tyr128 and Tyr129 Thus far, only a single tyrosine-specific kinase, protein-tyrosine kinase A (PtkA), encoded by the Rv223 ...[more]

PMID: 29884774

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Project description:UnlabelledIn Bacillus subtilis, biosynthesis of exopolysaccharide (EPS), a key biofilm matrix component, is regulated at the posttranslational level by the bacterial tyrosine kinase (BY-kinase) EpsB. EpsB, in turn, relies on the cognate kinase activator EpsA for activation. A concerted role of a second BY-kinase-kinase activator pair, PtkA and TkmA, respectively in biofilm formation was also indicated in previous studies. However, the exact functions of PtkA and TkmA in biofilm formation remain unclear. In this work, we show that the kinase activator TkmA contributes to biofilm formation largely independently of the cognate kinase, PtkA. We further show that the biofilm defect caused by a ?tkmA mutation can be rescued by complementation by epsA, suggesting a functional overlap between TkmA and EpsA and providing a possible explanation for the role of TkmA in biofilm formation. We also show that the importance of TkmA in biofilm formation depends largely on medium conditions; the biofilm defect of ?tkmA is very severe in the biofilm medium LBGM (lysogenic broth [LB] supplemented with 1% [vol/vol] glycerol and 100 ?M MnSO4) but marginal in another commonly used biofilm medium, MSgg (5 mM potassium phosphate [pH 7.0], MOPS [100 mM morpholinepropanesulfonic acid] [pH 7.0], 2 mM MgCl2, 700 ?M CaCl2, 50 ?M MnCl2, 50 ?M FeCl3, 1 ?M ZnCl2, 2 ?M thiamine, 0.5% glycerol, 0.5% glutamic acid, 50 ?g/ml tryptophan, 50 ?g/ml threonine, and 50 ?g/ml phenylalanine). The molecular basis for the medium dependence is likely due to differential expression of tkmA and epsA in the two different media and complex regulation of these genes by both Spo0A and DegU. Our studies provide genetic evidence for possible cross talk between a BY-kinase activator (TkmA) and a noncognate kinase (EpsB) and an example of how environmental conditions may influence such cross talk in regulating biofilm formation in B. subtilis.ImportanceIn bacteria, biosynthesis of secreted polysaccharides is often regulated by bacterial tyrosine kinases (BY-kinases). BY-kinases, in turn, rely on cognate kinase activators for activation. In this study, we investigated the role of a BY-kinase activator in biofilm formation in Bacillus subtilis. We present evidence that different BY-kinase activators may functionally overlap each other, as well as an example of how activities of the BY-kinase activators may be highly dependent on environmental conditions. Our study broadens the understanding of the complexity of regulation of the BY-kinases/kinase activators and the influence on bacterial cell physiology.

Dataset Information

The domain architecture of PtkA, the first tyrosine kinase from Mycobacterium tuberculosis, differs from the conventional kinase architecture.

Publications

The domain architecture of PtkA, the first tyrosine kinase from <i>Mycobacterium tuberculosis</i>, differs from the conventional kinase architecture.

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