Related Experiment Video

Updated: Mar 30, 2026

Fluorescence Assays for the Study of Mycobacterium tuberculosis Interaction with the Immune Receptor SLAMF1
07:42

Fluorescence Assays for the Study of Mycobacterium tuberculosis Interaction with the Immune Receptor SLAMF1

Published on: February 28, 2025

1.0K

A Role for IFITM Proteins in Restriction of Mycobacterium tuberculosis Infection

Shahin Ranjbar1, Viraga Haridas1, Luke D Jasenosky1

  • 1Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, MA 02115, USA.

Cell Reports
|November 14, 2015
PubMed

Insights

Interferon-induced transmembrane (IFITM) proteins restrict Mycobacterium tuberculosis growth. IFITM proteins enhance endosomal acidification, crucial for antimycobacterial activity against this intracellular bacterium.

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • Interferon (IFN)-induced transmembrane (IFITM) proteins are known mediators of host antiviral responses.
  • Their role in bacterial infections, particularly against intracellular pathogens, remains less understood.

Purpose of the Study:

  • To investigate the role of IFITM proteins in host defense against intracellular bacterial infection by Mycobacterium tuberculosis (MTb).
  • To determine if IFITM proteins restrict MTb intracellular growth and elucidate the underlying mechanisms.

Main Methods:

  • RNA interference (RNAi) for simultaneous knockdown of IFITM1, IFITM2, and IFITM3.
  • Overexpression of individual IFITM proteins in human monocytic and alveolar/epithelial cells.
  • Analysis of MTb growth, IFITM gene expression induction by MTb, TLR ligands, and cytokines.
  • Confocal microscopy to assess IFITM3 co-localization with MTb phagosomes.
  • Measurement of endosomal acidification in infected cells.

Main Results:

  • Simultaneous knockdown of IFITM1-3 significantly enhanced MTb growth.
  • Individual overexpression of IFITM1, IFITM2, or IFITM3 impaired MTb growth.
  • MTb infection, TLR2/4 ligands, and cytokines induced IFITM1-3 expression in myeloid cells.
  • IFITM3 co-localized with MTb phagosomes and enhanced their acidification.

Conclusions:

  • IFITM proteins play a critical role in restricting intracellular Mycobacterium tuberculosis growth.
  • IFITM-mediated endosomal maturation, specifically acidification, is implicated in the antimycobacterial activity of these proteins.
  • This study expands the known functions of IFITM proteins beyond antiviral defense to include host defense against mycobacteria.

More Related Videos

Preparation of Mycobacterium Tuberculosis Culture Filtrate to Understand TB Pathogenesis07:32

Preparation of Mycobacterium Tuberculosis Culture Filtrate to Understand TB Pathogenesis

Published on: March 28, 2025

1.3K
A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection10:10

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Published on: October 5, 2015

19.6K

Related Concept Videos

Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
15.4K
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors...
10.9K
Cytoskeletal Proteins in Bacteria01:29

Cytoskeletal Proteins in Bacteria

Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
4.5K
Pulmonary Tuberculosis V01:28

Pulmonary Tuberculosis V

Medical management of tuberculosis (TB) patients involves a comprehensive approach that includes diagnosis, treatment, and monitoring. The specific strategies can vary depending on the type of tuberculosis (latent or active), the patient's overall health status, and other considerations.
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the...
864
Pulmonary Tuberculosis II01:28

Pulmonary Tuberculosis II

Tuberculosis, or TB, is a bacterial infectious disease caused by Mycobacterium tuberculosis. While its primary impact is on the lungs, leading to pulmonary tuberculosis, it can also affect various other organs, a condition referred to as extrapulmonary tuberculosis.
Here is a detailed explanation of its pathophysiology:
Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
2.1K
Regulation of the Unfolded Protein Response01:31

Regulation of the Unfolded Protein Response

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
3.2K