Mycobacterium tuberculosis MycP1 Protease Plays a Dual Role in Regulation of ESX-1 Secretion and Virulence

Ohol, Yamini M.; Goetz, David H.; Chan, Kaman; Shiloh, Michael U.; Craik, Charles S.; Cox, Jeffery S.

doi:10.1016/j.chom.2010.02.006

Cited by 133 publications

(193 citation statements)

References 51 publications

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“…This could mean that processing of ESX-5 substrates is a common process, similar to the removal of a signal sequence. Interestingly, processing has also been observed for the ESX-1 substrate EspB (16), which was recently shown to be cleaved by the ESX-1-encoded protease MycP1 (47). To further investigate the nature of the LipY tub cleavage site, we altered the neighboring residues using site-directed mutagenesis.…”

Section: Discussionmentioning

confidence: 99%

Conserved Pro-Glu (PE) and Pro-Pro-Glu (PPE) Protein Domains Target LipY Lipases of Pathogenic Mycobacteria to the Cell Surface via the ESX-5 Pathway

Daleke

Cascioferro

Punder

et al. 2011

Journal of Biological Chemistry

126

181

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The type VII secretion system ESX-5 is a major pathway for export of PE and PPE proteins in pathogenic mycobacteria. These mycobacteria-specific protein families are characterized by conserved N-terminal domains of 100 and 180 amino acids, which contain the proline-glutamic acid (PE) and proline-proline-glutamic acid (PPE) motifs after which they are named. Here we investigated secretion of the triacylglycerol lipase LipY, which in fast-growing mycobacteria contains a signal sequence, but in slow-growing species appears to have replaced the signal peptide with a PE or PPE domain. Selected LipY homologues were expressed in wild-type Mycobacterium marinum and its corresponding ESX-5 mutant, and localization of the proteins was investigated by immunoblotting and electron microscopy. Our study shows that Mycobacterium tuberculosis PE-LipY (LipY tub ) and M. marinum PPE-LipY (LipY mar ) are both secreted to the bacterial surface in an ESX-5-dependent fashion. After transport, the PE/PPE domains are removed by proteolytic cleavage. In contrast, Mycobacterium gilvum LipY, which has a signal sequence, is not transported to the cell surface. Furthermore, we show that LipY tub and LipY mar require their respective PE and PPE domains for ESX-5-dependent secretion. The role of the PE domain in ESX-5 secretion was confirmed in a whole cell lipase assay, in which wild-type bacteria expressing full-length LipY tub , but not LipY tub lacking its PE domain, were shown to hydrolyze extracellular lipids. In conclusion, both PE and PPE domains contain a signal required for secretion of LipY by the ESX-5 system, and these domains are proteolytically removed upon translocation.Mycobacteria such as Mycobacterium tuberculosis, the etiological agent of tuberculosis, have a highly unusual and complex cell envelope (1). To secrete virulence factors across the cell envelope, these bacteria use specialized protein secretion systems, known as ESX or type VII secretion systems (2-8). Mycobacterial genomes contain up to five genetic loci coding for type VII secretion systems, named ESX-1 to ESX-5 (9, 10). The most well studied system, ESX-1, is responsible for the secretion of 10 substrates, including the important T-cell antigens ESAT-6 and CFP-10, and is required for full virulence of M. tuberculosis (7,(11)(12)(13)(14)(15)(16)(17). Phylogenetic analyses and comparative genomics suggest that the five ESX clusters have evolved by gene duplication and that ESX-5 is the result of the most recent duplication event (9). Interestingly, ESX-5 is restricted to a group of mycobacterial species known as the slow-growing mycobacteria, which include all major pathogens, such as M. tuberculosis, Mycobacterium leprae, and Mycobacterium ulcerans, and the fish pathogen Mycobacterium marinum (9). Four of the ESX loci contain also PE and PPE genes (named after the conserved Pro-Glu (PE) and Pro-Pro-Glu (PPE) motifs near the N termini of their respective gene products) (9, 10), and the appearance of ESX-5 predates the huge expansion of these gene families in s...

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Section: Discussionmentioning

confidence: 99%

Conserved Pro-Glu (PE) and Pro-Pro-Glu (PPE) Protein Domains Target LipY Lipases of Pathogenic Mycobacteria to the Cell Surface via the ESX-5 Pathway

Daleke

Cascioferro

Punder

et al. 2011

Journal of Biological Chemistry

126

181

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“…5A, bottom). Additionally, Rv-D981 does not appear to have a general defect in protein export, as evidenced by the normal extracellular levels of Mpt32, a protein secreted independently of ESX-1 (41).…”

Section: Figmentioning

confidence: 99%

MprAB Regulates theespAOperon in Mycobacterium tuberculosis and Modulates ESX-1 Function and Host Cytokine Response

et al. 2013

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dThe ESX-1 secretion system exports the immunomodulatory protein ESAT-6 and other proteins important in the pathogenesis of Mycobacterium tuberculosis. Components and substrates of ESX-1 are encoded at several loci, but the regulation of the encoding genes is only partially understood. In this study, we investigated the role of the MprAB two-component system in the regulation of ESX-1 activity. We determined that MprAB directly regulates the espA gene cluster, a locus necessary for ESX-1 function. Transcript mapping determined that the five genes in the cluster form an operon with two transcriptional start points, and several MprA binding sites were detected in the espA promoter. Expression analyses and promoter constructs indicated that MprAB represses the espA operon. However, the MprAB mutant Rv-D981 secreted lower levels of EspA, ESAT-6, and the ESX-1 substrate EspB than control strains. Secretion of CFP10, which is normally cosecreted with ESAT-6, was similar in Rv-D981 and control strains, further demonstrating aberrant ESX-1 activity in the mutant. ESAT-6 induces proinflammatory cytokines, and macrophages infected with Rv-D981 elicited lower levels of interleukin 1␤ (IL-1␤) and tumor necrosis factor alpha (TNF-␣), consistent with the reduced levels of ESAT-6. These findings indicate that MprAB modulates ESX-1 function and reveal a new role for MprAB in host-pathogen interactions.

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“…All ESX systems also include membrane-bound mycobacteria-specific subtilisin-like serine proteases called mycosins (MycP 1 -MycP 5 ) (123,124), which might be involved in proteolytic digestion of ESX substrates. The ESX-1-associated MycP1, the only mycosin characterized so far, plays a key role in modulation of ESX-1 secretion activity, via the proteolytic digestion of the ESX-1 substrate EspB (125).…”

Section: Mycobacterial Systems Discovered By Genomics That Are Involvmentioning

confidence: 99%

Mycobacterial Pathogenomics and Evolution

et al. 2014

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Most mycobacterial species are harmless saprophytes, often found in aquatic environments. A few species seem to have evolved from this pool of environmental mycobacteria into major human pathogens, such as Mycobacterium tuberculosis, the agent of tuberculosis, Mycobacterium leprae, the leprosy bacillus, and Mycobacterium ulcerans, the agent of Buruli ulcer. While the pathogenicity of M. ulcerans relates to the acquisition of a large plasmid encoding a polyketide-derived toxin, the molecular mechanisms by which M. leprae or M. tuberculosis have evolved to cause disease are complex and involve the interaction between the pathogen and the host.Here we focus on M. tuberculosis and closely related mycobacteria and discuss insights gained from recent genomic and functional studies. Comparison of M. tuberculosis genome data with sequences from nontuberculous mycobacteria, such as Mycobacterium marinum or Mycobacterium kansasii, provides a perception of the more distant evolution of M. tuberculosis, while the recently accomplished genome sequences of multiple tubercle bacilli with smooth colony morphology, named Mycobacterium canettii, have allowed the ancestral gene pool of tubercle bacilli to be estimated. The resulting findings are instrumental for our understanding of the pathogenomic evolution of tuberculosis-causing mycobacteria. Comparison of virulent and attenuated members of the M. tuberculosis complex has further contributed to identification of a specific secretion pathway, named ESX or Type VII secretion. The molecular machines involved are key elements for mycobacterial pathogenicity, strongly influencing the ability of M. tuberculosis to cope with the immune defense mounted by the host.

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Mycobacterium tuberculosis MycP1 Protease Plays a Dual Role in Regulation of ESX-1 Secretion and Virulence

Cited by 133 publications

References 51 publications

Conserved Pro-Glu (PE) and Pro-Pro-Glu (PPE) Protein Domains Target LipY Lipases of Pathogenic Mycobacteria to the Cell Surface via the ESX-5 Pathway

Conserved Pro-Glu (PE) and Pro-Pro-Glu (PPE) Protein Domains Target LipY Lipases of Pathogenic Mycobacteria to the Cell Surface via the ESX-5 Pathway

MprAB Regulates theespAOperon in Mycobacterium tuberculosis and Modulates ESX-1 Function and Host Cytokine Response

Mycobacterial Pathogenomics and Evolution

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