Related Experiment Video

Updated: Jul 10, 2026

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions
12:52

Use of Shigella flexneri to Study Autophagy-Cytoskeleton Interactions

Published on: September 9, 2014

A role for Nod-like receptors in autophagy induced by Shigella infection

Toshihiko Suzuki1, Gabriel Núñez

  • 1Division of Bacterial Pathogenesis, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan. t-suzuki@med.u-ryukyu.ac.jp

Autophagy
|October 13, 2007
PubMed

Insights

Shigella infection triggers cell death via the Ipaf inflammasome in macrophages. Autophagy, regulated by Ipaf, provides transient resistance to this cell death, revealing a new role for NLR proteins in host defense.

Area of Science:

  • Immunology
  • Cell Biology
  • Microbiology

Background:

  • Shigella infection causes bacillary dysentery, inducing caspase-1 activation and cell death in macrophages.
  • The precise mechanisms of Shigella-induced macrophage cell death remain unclear.

Purpose of the Study:

  • To elucidate the molecular mechanisms of Shigella-induced pyroptosis in macrophages.
  • To investigate the role of Ipaf, ASC, and caspase-1 in this process.
  • To explore the relationship between autophagy and pyroptosis during Shigella infection.

Main Methods:

  • Macrophage infection with Shigella.
  • Analysis of caspase-1 activation and IL-1beta processing.
  • Assessment of pyroptosis and autophagy induction.
  • Gene silencing or knockout of Ipaf, ASC, and caspase-1.

Main Results:

  • Shigella-induced caspase-1 activation and IL-1beta processing are mediated by Ipaf and ASC.
  • Ipaf and caspase-1 are essential for pyroptosis, while ASC is dispensable.
  • Shigella infection induces autophagy, which is significantly enhanced in the absence of caspase-1 or Ipaf.
  • Autophagy induction correlates with transient resistance to pyroptosis.

Conclusions:

  • The Ipaf inflammasome is a key regulator of Shigella-induced pyroptosis in macrophages.
  • Autophagy is regulated by the Ipaf inflammasome and confers transient resistance to pyroptosis.
  • NLR proteins play a novel role in modulating bacterial-host interactions through the regulation of autophagy and cell death pathways.

More Related Videos

Imaging Ca2+ Responses During Shigella Infection of Epithelial Cells08:56

Imaging Ca2+ Responses During Shigella Infection of Epithelial Cells

Published on: May 24, 2018

Related Concept Videos

Delivery Pathways to the Lysosome01:36

Delivery Pathways to the Lysosome

Eukaryotic cells use different mechanisms to eliminate toxic waste obsolete and worn-out substances. Lysosomes play a pivotal role in this, and hence, these substances are carried to the lysosome from other parts of the cell and extracellular space through different pathways. The most elaborately studied pathways to the lysosome are the endocytic pathways.
Endocytosis
In endocytosis, the cell membrane takes up macromolecules and particles from the surrounding medium. Clathrin-mediated...
Autophagy01:27

Autophagy

Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
Recycling Endosomes and Transcytosis00:58

Recycling Endosomes and Transcytosis

The recycling endosome, also known as the endosomal recycling compartment (ERC), is a part of the slow-recycling process of the endocytic pathway. Molecules internalized through receptor-mediated endocytosis are either degraded in the lysosomes or are recycled to the plasma membrane through the fast- or slow-recycling route.
The recycling endosome is not a single organelle but an extensively tubulated network of recycling pathways. It functions in storing molecules or transporting them across...
Role Of Notch Signalling In Intestinal Stem Cell Renewal01:12

Role Of Notch Signalling In Intestinal Stem Cell Renewal

Notch signaling was first discovered in Drosophila melanogaster, where it is involved in cell lineage differentiation. Notch signaling regulates the maintenance and differentiation of intestinal stem cells or ISCs by controlling the expression of atonal homolog 1 or Atoh1. Atoh1 directs cells to differentiate into secretory cells.
Direct cell-to-cell contact is needed for the activation of Notch signaling. The signal is initiated when a notch ligand binds to a receptor on an adjacent cell, also...
Cellular Injury V: Apoptosis and Autophagy01:22

Cellular Injury V: Apoptosis and Autophagy

Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...
Autophagic Cell Death01:18

Autophagic Cell Death

Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...