Related Experiment Video

Updated: Jul 13, 2026

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM)
10:07

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM)

Published on: August 26, 2016

Bacteria-generated PtdIns(3)P recruits VAMP8 to facilitate phagocytosis

Shipan Dai1, Ying Zhang, Thomas Weimbs

  • 1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.

Traffic (Copenhagen, Denmark)
|July 25, 2007
PubMed

Insights

Salmonella Typhimurium uses SopB to generate PtdIns(3)P, which recruits VAMP8/endobrevin. This interaction enhances bacterial entry into host cells by promoting macropinocytosis.

Area of Science:

  • Microbiology
  • Cell Biology
  • Molecular Biology

Background:

  • Salmonella enterica serovar Typhimurium invasion of non-phagocytic cells occurs via macropinocytosis.
  • The SopB protein is crucial for modulating actin dynamics and facilitating Salmonella-induced invasion.

Purpose of the Study:

  • To investigate the role of SopB-generated phosphatidylinositol 3-phosphate (PtdIns(3)P) in Salmonella invasion.
  • To determine the interaction between PtdIns(3)P and VAMP8/endobrevin in bacterial phagocytosis.

Main Methods:

  • Investigating VAMP8 recruitment to Salmonella-induced macropinosomes using nocodazole and Brefeldin A.
  • Assessing the binding and colocalization of VAMP8 with PtdIns(3)P.
  • Evaluating the impact of SopB's inositol phosphatase activity and wortmannin on PtdIns(3)P and VAMP8 levels.
  • Analyzing Salmonella invasion levels after VAMP8 knockdown or expression of truncated VAMP8.

Main Results:

  • SopB-generated PtdIns(3)P binds to VAMP8/endobrevin, enhancing bacterial phagocytosis.
  • VAMP8 is recruited to macropinosomes in a nocodazole-dependent, Brefeldin A-independent manner.
  • SopB's phosphatase activity is essential for PtdIns(3)P and VAMP8 accumulation; wortmannin has no effect.
  • VAMP8 knockdown or truncation significantly reduces Salmonella invasion.

Conclusions:

  • Salmonella Typhimurium utilizes SopB to generate PtdIns(3)P, which recruits VAMP8/endobrevin.
  • This interaction is critical for efficient Salmonella entry into host cells via macropinocytosis.
  • The study highlights Salmonella's exploitation of host SNARE proteins and vesicle trafficking for invasion.

More Related Videos

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages10:33

Isolation of Salmonella typhimurium-containing Phagosomes from Macrophages

Published on: October 25, 2017

Related Concept Videos

DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Phagocytosis00:41

Phagocytosis

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis ("cellular eating") is one of three major types of endocytosis. Cells use phagocytosis to take in large objects, such as other cells (or their debris), bacteria, and even viruses.
The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). Many immune system cells, including...
Phagocytosis00:41

Phagocytosis

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis (“cellular eating”) is one of three major types of endocytosis. Cells use phagocytosis to take in large objects—such as other cells (or their debris), bacteria, and even viruses.The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). It is perhaps unsurprising, that many...
Lytic Cycle of Bacteriophages01:30

Lytic Cycle of Bacteriophages

Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the lytic replication...
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Intracellular Movement of Viruses and Bacteria01:10

Intracellular Movement of Viruses and Bacteria

Intracellular bacteria and viruses often comprise a group of highly infectious pathogens that can cause several diseases. Bacterial pathogens include those belonging to the genus Rickettsia responsible for conditions such as rocky mountain spotted fever and the Mediterranean spotted fever; Chlamydia, a genus responsible for a sexually transmitted disease; Coxiella burnetii, an agent responsible for Q fever. Viral pathogens include vaccinia—a poxvirus, and herpes simplex virus—a virus that...