PUBLICATION
EspH is a hypervirulence factor for Mycobacterium marinum and essential for the secretion of the ESX-1 substrates EspE and EspF
- Authors
- Phan, T.H., van Leeuwen, L.M., Kuijl, C., Ummels, R., van Stempvoort, G., Rubio-Canalejas, A., Piersma, S.R., Jiménez, C.R., van der Sar, A.M., Houben, E.N.G., Bitter, W.
- ID
- ZDB-PUB-180814-15
- Date
- 2018
- Source
- PLoS pathogens 14: e1007247 (Journal)
- Registered Authors
- Bitter, Wilbert, van der Sar, Astrid M.
- Keywords
- none
- MeSH Terms
-
- Animals
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism*
- Cells, Cultured
- Embryo, Nonmammalian
- Larva
- Mice
- Mycobacterium marinum/genetics
- Mycobacterium marinum/metabolism*
- Mycobacterium marinum/pathogenicity*
- RAW 264.7 Cells
- Sheep
- Type VII Secretion Systems/genetics*
- Type VII Secretion Systems/metabolism
- Virulence/genetics
- Virulence Factors/genetics
- Virulence Factors/physiology*
- Zebrafish/embryology
- Zebrafish/growth & development
- PubMed
- 30102741 Full text @ PLoS Pathog.
Citation
Phan, T.H., van Leeuwen, L.M., Kuijl, C., Ummels, R., van Stempvoort, G., Rubio-Canalejas, A., Piersma, S.R., Jiménez, C.R., van der Sar, A.M., Houben, E.N.G., Bitter, W. (2018) EspH is a hypervirulence factor for Mycobacterium marinum and essential for the secretion of the ESX-1 substrates EspE and EspF. PLoS pathogens. 14:e1007247.
Abstract
The pathogen Mycobacterium tuberculosis employs a range of ESX-1 substrates to manipulate the host and build a successful infection. Although the importance of ESX-1 secretion in virulence is well established, the characterization of its individual components and the role of individual substrates is far from complete. Here, we describe the functional characterization of the Mycobacterium marinum accessory ESX-1 proteins EccA1, EspG1 and EspH, i.e. proteins that are neither substrates nor structural components. Proteomic analysis revealed that EspG1 is crucial for ESX-1 secretion, since all detectable ESX-1 substrates were absent from the cell surface and culture supernatant in an espG1 mutant. Deletion of eccA1 resulted in minor secretion defects, but interestingly, the severity of these secretion defects was dependent on the culture conditions. Finally, espH deletion showed a partial secretion defect; whereas several ESX-1 substrates were secreted in normal amounts, secretion of EsxA and EsxB was diminished and secretion of EspE and EspF was fully blocked. Interaction studies showed that EspH binds EspE and therefore could function as a specific chaperone for this substrate. Despite the observed differences in secretion, hemolytic activity was lost in all M. marinum mutants, implying that hemolytic activity is not strictly correlated with EsxA secretion. Surprisingly, while EspH is essential for successful infection of phagocytic host cells, deletion of espH resulted in a significantly increased virulence phenotype in zebrafish larvae, linked to poor granuloma formation and extracellular outgrowth. Together, these data show that different sets of ESX-1 substrates play different roles at various steps of the infection cycle of M. marinum.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping