Mycobacterium tuberculosis universal stress protein Rv2623 interacts with the putative ATP binding cassette (ABC) transporter Rv1747 to regulate mycobacterial growth
| Autor: | Guofeng Zhu, Jordi B. Torrelles, Catherine Vilchèze, Sivagami Sundaram Chavadi, Simren Mehta, Lijun Bi, Ganduri Swapna, William R. Jacobs, Steven A. Porcelli, Kaixia Mi, TuKiet T. Lam, Syun-Ru Yeh, JoAnn M. Tufariello, Chenyang Zhan, John Chan, Jesus Arcos, Steve C. Almo, Lisa N. Glass, Joshua E. Drumm, Yong Chen |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Threonine Mutant ATP-binding cassette transporter Plasma protein binding Biochemistry Mutant protein Yeast Two-Hybrid Assays Two-Hybrid Screening Biology (General) Post-Translational Modification Phosphorylation Amino Acids Gel Electrophoresis Organic Compounds 3. Good health Actinobacteria Chemistry Phenotypes Physical Sciences Protein Interaction Assays Research Article Protein Binding QH301-705.5 030106 microbiology Immunology Protein domain Library Screening Biology Research and Analysis Methods Microbiology Protein–protein interaction 03 medical and health sciences Electrophoretic Techniques Bacterial Proteins Protein Domains Virology Hydroxyl Amino Acids Two-Hybrid System Techniques Genetics Humans Tuberculosis Molecular Biology Techniques Protein Interactions Molecular Biology Molecular Biology Assays and Analysis Techniques Bacteria Organic Chemistry Organisms Chemical Compounds Biology and Life Sciences Proteins Mycobacterium tuberculosis RC581-607 Phosphate-Binding Proteins 030104 developmental biology Parasitology ATP-Binding Cassette Transporters Immunologic diseases. Allergy Carrier Proteins |
| Zdroj: | PLoS Pathogens PLoS Pathogens, Vol 13, Iss 7, p e1006515 (2017) |
| ISSN: | 1553-7374 1553-7366 |
| Popis: | We have previously shown that the Mycobacterium tuberculosis universal stress protein Rv2623 regulates mycobacterial growth and may be required for the establishment of tuberculous persistence. Here, yeast two-hybrid and affinity chromatography experiments have demonstrated that Rv2623 interacts with one of the two forkhead-associated domains (FHA I) of Rv1747, a putative ATP-binding cassette transporter annotated to export lipooligosaccharides. FHA domains are signaling protein modules that mediate protein-protein interactions to modulate a wide variety of biological processes via binding to conserved phosphorylated threonine (pT)-containing oligopeptides of the interactors. Biochemical, immunochemical and mass spectrometric studies have shown that Rv2623 harbors pT and specifically identified threonine 237 as a phosphorylated residue. Relative to wild-type Rv2623 (Rv2623WT), a mutant protein in which T237 has been replaced with a non-phosphorylatable alanine (Rv2623T237A) exhibits decreased interaction with the Rv1747 FHA I domain and diminished growth-regulatory capacity. Interestingly, compared to WT bacilli, an M. tuberculosis Rv2623 null mutant (ΔRv2623) displays enhanced expression of phosphatidyl-myo-inositol mannosides (PIMs), while the ΔRv1747 mutant expresses decreased levels of PIMs. Animal studies have previously shown that ΔRv2623 is hypervirulent, while ΔRv1747 is growth-attenuated. Collectively, these data have provided evidence that Rv2623 interacts with Rv1747 to regulate mycobacterial growth; and this interaction is mediated via the recognition of the conserved Rv2623 pT237-containing FHA-binding motif by the Rv1747 FHA I domain. The divergent aberrant PIM profiles and the opposing in vivo growth phenotypes of ΔRv2623 and ΔRv1747, together with the annotated lipooligosaccharide exporter function of Rv1747, suggest that Rv2623 interacts with Rv1747 to modulate mycobacterial growth by negatively regulating the activity of Rv1747; and that Rv1747 might function as a transporter of PIMs. Because these glycolipids are major mycobacterial cell envelope components that can impact on the immune response, our findings raise the possibility that Rv2623 may regulate bacterial growth, virulence, and entry into persistence, at least in part, by modulating the levels of bacillary PIM expression, perhaps through negatively regulating the Rv1747-dependent export of the immunomodulatory PIMs to alter host-pathogen interaction, thereby influencing the fate of M. tuberculosis in vivo. Author summary Mycobacterium tuberculosis remains a significant public health burden worldwide. The tubercle bacillus can establish a clinically silent latent infection in the host, which can subsequently reactivate to cause diseases, resulting in transmission of the pathogen. We have previously shown that the M. tuberculosis universal stress protein Rv2623 has the ability to regulate mycobacterial growth and may be required for the establishment of latent infection. The present study is undertaken to better understand the mechanisms by which Rv2623 regulates M. tuberculosis growth. Our results have revealed that Rv2623 interacts with Rv1747, a putative exporter of lipooligosaccharides, to negatively regulate mycobacterial growth. We have defined the molecular elements in these two proteins that mediate their interaction. We have further shown that relative to the wild-type (WT) bacillus, an Rv2623 null mutant (ΔRv2623) exhibits a higher content of phosphatidyl-myo-inositol mannosides (PIMs), immunologically active molecules of the M. tuberculosis cell envelope. By contrast, ΔRv1747 produces less PIMs than WT. Of note, while ΔRv2623 is hypervirulent, ΔRv1747 is hypovirulent in mice. These observations link the growth-regulatory attributes of Rv2623 to the function of Rv1747, suggesting that Rv2623 may regulate M. tuberculosis growth by modulating Rv1747’s export of the immunomodulatory PIMs. Defining how Rv2623 regulates mycobacterial growth will likely provide insight into the mechanisms underlying tuberculous latency and reactivation, processes that play important roles in M. tuberculosis pathogenesis. |
| Databáze: | OpenAIRE |
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