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Updated: Apr 16, 2026
Separation and Fractionation of Cell Wall and Cell Membrane Proteins from Mycobacterium tuberculosis for Downstream Protein Analysis
Published on: September 26, 2025
Quantitative Proteomics and Lipidomics Analysis of Endoplasmic Reticulum of Macrophage Infected with Mycobacterium
Najmuddin Mohd Saquib1, Shilpa Jamwal2, Mukul Kumar Midha2
1Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India ; School of Life Sciences, Jaipur National University, Jaipur 302025, India.
Abstract:
Even though endoplasmic reticulum (ER) stress associated with mycobacterial infection has been well studied, the molecular basis of ER as a crucial organelle to determine the fate of Mtb is yet to be established. Here, we have studied the ability of Mtb to manipulate the ultrastructural architecture of macrophage ER and found that the ER-phenotypes associated with virulent (H37Rv) and avirulent (H37Ra) strains were different: a rough ER (RER) with the former against a smooth ER (SER) with the later. Further, the functional attributes of these changes were probed by MS-based quantitative proteomics (133 ER proteins) and lipidomics (8 phospholipids). Our omics approaches not only revealed the host pathogen cross-talk but also emphasized how precisely Mtb uses proteins and lipids in combination to give rise to characteristic ER-phenotypes. H37Ra-infected macrophages increased the cytosolic Ca(2+) levels by attenuating the ATP2A2 protein and simultaneous induction of PC/PE expression to facilitate apoptosis. However, H37Rv inhibited apoptosis and further controlled the expression of EST-1 and AMRP proteins to disturb cholesterol homeostasis resulting in sustained infection. This approach offers the potential to decipher the specific roles of ER in understanding the cell biology of mycobacterial infection with special reference to the impact of host response.
Insights
Mycobacterium tuberculosis (Mtb) manipulates macrophage endoplasmic reticulum (ER) structure, altering protein and lipid expression to control host cell fate and establish infection. Virulent Mtb promotes ER changes that sustain infection, while avirulent Mtb induces apoptosis.
Area of Science:
- Cell Biology
- Microbiology
- Immunology
Background:
- Endoplasmic reticulum (ER) stress in mycobacterial infection is known, but its role in determining Mycobacterium tuberculosis (Mtb) fate is unclear.
- The precise molecular mechanisms by which Mtb manipulates the host ER remain to be fully elucidated.
Purpose of the Study:
- To investigate how Mtb manipulates the ultrastructural architecture of the macrophage ER.
- To understand the molecular basis of ER's role in Mtb infection outcome.
Main Methods:
- Comparative analysis of ER ultrastructure in macrophages infected with virulent (H37Rv) and avirulent (H37Ra) Mtb strains.
- Mass spectrometry-based quantitative proteomics of 133 ER proteins and lipidomics of 8 phospholipids.
- Analysis of host cell apoptosis and cholesterol homeostasis.
Main Results:
- Virulent H37Rv induced a rough ER (RER) phenotype, while avirulent H37Ra induced a smooth ER (SER) phenotype.
- H37Ra-infected macrophages increased cytosolic Ca(2+) and induced PC/PE expression, facilitating apoptosis.
- H37Rv inhibited apoptosis, disturbed cholesterol homeostasis via EST-1 and AMRP proteins, leading to sustained infection.
Conclusions:
- Mtb precisely utilizes host proteins and lipids to create distinct ER phenotypes, influencing infection outcome.
- The ER's role in mycobacterial infection is critical, with specific manipulations by Mtb strains dictating host response and infection persistence.
