Purification and structural characterization of Mce4A from Mycobacterium tuberculosis

Khan, Shahjahan; Islam, Asimul; Hassan, Md. Imtaiyaz; Ahmad, Faizan

doi:10.1016/j.ijbiomac.2016.06.059

Cited by 11 publications

(8 citation statements)

References 36 publications

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“…This suggests that there may be additional secreted virulence proteins from Mtb that associate with the host membranes than our screen identified. Indeed, while we corroborated previously known membrane-interacting proteins such as the SecA2 secreted PI3P phosphatase SapM (17, 18), the Rac1-binding protein Ndk (119), and the cholesterol-binding Mce4A (120), we failed to identify others such as LipY which hydrolyzes extracellular lipids (121) and the ESX1 substrate ESAT-6, whose ability to directly interact with the phagosomal membrane (122, 123) has recently been questioned (65, 124).…”

Section: Discussionsupporting

confidence: 84%

Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector

Stamm

Pasko

Chaisavaneeyakorn

et al. 2019

mSphere

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Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is one of the most successful human pathogens. One reason for its success is that Mtb can reside within host macrophages, a cell type that normally functions to phagocytose and destroy infectious bacteria. However, Mtb is able to evade macrophage defenses in order to survive for prolonged periods of time. Many intracellular pathogens secrete virulence factors targeting host membranes and organelles to remodel their intracellular environmental niche. We hypothesized that Mtb secreted proteins that target host membranes are vital for Mtb to adapt to and manipulate the host environment for survival. Thus, we characterized 200 secreted proteins from Mtb for their ability to associate with eukaryotic membranes using a unique temperature-sensitive yeast screen and to manipulate host trafficking pathways using a modified inducible secretion screen. We identified five Mtb secreted proteins that both associated with eukaryotic membranes and altered the host secretory pathway. One of these secreted proteins, Mpt64, localized to the endoplasmic reticulum during Mtb infection of murine and human macrophages and impaired the unfolded protein response in macrophages. These data highlight the importance of secreted proteins in Mtb pathogenesis and provide a basis for further investigation into their molecular mechanisms. IMPORTANCE Advances have been made to identify secreted proteins of Mycobacterium tuberculosis during animal infections. These data, combined with transposon screens identifying genes important for M. tuberculosis virulence, have generated a vast resource of potential M. tuberculosis virulence proteins. However, the function of many of these proteins in M. tuberculosis pathogenesis remains elusive. We have integrated three cell biological screens to characterize nearly 200 M. tuberculosis secreted proteins for eukaryotic membrane binding, host subcellular localization, and interactions with host vesicular trafficking. In addition, we observed the localization of one secreted protein, Mpt64, to the endoplasmic reticulum (ER) during M. tuberculosis infection of macrophages. Interestingly, although Mpt64 is exported by the Sec pathway, its delivery into host cells was dependent upon the action of the type VII secretion system. Finally, we observed that Mpt64 impairs the ER-mediated unfolded protein response in macrophages.

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Section: Discussionsupporting

confidence: 84%

Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector

Stamm

Pasko

Chaisavaneeyakorn

et al. 2019

mSphere

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“…This suggests that there may be additional secreted virulence proteins from Mtb that associate with the host membranes than our screen identified. Indeed, while we corroborated previously known membrane-interacting proteins such as the SecA2-secreted PI3P phosphatase SapM (17, 18), the Rac1-binding protein Ndk (96) and the cholesterol-binding Mce4A (97), we failed to identify others such as LipY which hydrolyzes extracellular lipids (98) and the ESX1 substrate ESAT-6 which interacts with the phagosomal membrane (99, 100).…”

Section: Discussionsupporting

confidence: 75%

Screening Mycobacterium tuberculosis secreted proteins identifies Mpt64 as eukaryotic membrane-binding virulence factor

Stamm

Pasko

Chaisavaneeyakorn

et al. 2018

Preprint

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word count: 203 22 23 2 Text word count: 7,901 24 3 Abstract 25Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is one of the 26 most successful human pathogens. One reason for its success is that Mtb can reside 27 within host macrophages, a cell type that normally functions to phagocytose and destroy 28 infectious bacteria. However, Mtb is able to evade macrophage defenses in order to 29 survive for prolonged periods of time. Many intracellular pathogens secret virulence 30 factors targeting host membranes and organelles to remodel their intracellular 31 environmental niche. We hypothesized that Mtb exported proteins that target host 32 membranes are vital for Mtb to adapt to and manipulate the host environment for 33 survival. Thus, we characterized 200 exported proteins from Mtb for their ability to 34 associate with eukaryotic membranes using a unique temperature sensitive yeast 35 screen and to manipulate host trafficking pathways using a modified inducible secretion 36 screen. We identified five Mtb exported proteins that both associated with eukaryotic 37 membranes and altered the host secretory pathway. One of these secreted proteins, 38Mpt64, localized to the endoplasmic reticulum during Mtb infection of murine and human 39 macrophages and was necessary for Mtb survival in primary human macrophages. 40

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“…As with Mce1A, the Mce4A protein gives E. coli cells the ability to penetrate HeLa cells (Zhang and Xie, 2011). Deletion of the mce4 operon leads to a significant reduction in virulence Mycobacterium tuberculosis (Zhang and Xie, 2011;Khan et al, 2016). For Mce4F, participation in virulence (i.e., invasion) was predicted via analysis in silico (Rodríguez et al, 2015).…”

Section: Mce4 Operonmentioning

confidence: 99%

The Actinobacterial mce Operon: Structure and Functions

Zaichikova

Danilenko

2020

Biol Bull Rev

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The results of studies on mce operons of the causative agent Mycobacterium tuberculosis and actinobacteria are summarized. Mce transporters belong to a group of cell-wall proteins. The genome of M. tuberculosis contains four mce operons that encode complexes, each of which consists of two integral membrane proteins (YrbEB) followed by six other Mce proteins (MceA-F). These proteins are functionally similar to ABC transporters. Despite their significant role in the pathogenesis of M. tuberculosis infection, Mce proteins remain poorly studied due to their complex structure and operon regulation. However, a number of their functions have been characterized; they include the penetration of host cells by M. tuberculosis and its survival, as well as the transport of cholesterol and mycolic acids, which are pathogenicity factors of no small importance. The expression of mce operons depends on many factors, such as the growth phase, the culture medium, and the localization of M. tuberculosis infection. Today, strains of M. tuberculosis and M. bovis with deleted mce operons are considered candidates for the development of new attenuated vaccines that might one day replace the M. bovis BCG vaccine, which is no longer deemed strong enough to hold back the tuberculosis epidemic.

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Purification and structural characterization of Mce4A from Mycobacterium tuberculosis

Cited by 11 publications

References 36 publications

Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector

Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector

Screening Mycobacterium tuberculosis secreted proteins identifies Mpt64 as eukaryotic membrane-binding virulence factor

The Actinobacterial mce Operon: Structure and Functions

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