Related Experiment Video

Updated: Jul 15, 2025

Assaying for Inorganic Polyphosphate in Bacteria
07:20

Assaying for Inorganic Polyphosphate in Bacteria

Published on: January 21, 2019

8.7K

Polyphosphate uses mTOR, pyrophosphate, and Rho GTPase components to potentiate bacterial survival in Dictyostelium

Ryan J Rahman1, Ramesh Rijal1, Shiyu Jing1

  • 1Department of Biology, Texas A&M University , College Station, Texas, USA.

Mbio
|September 27, 2023
PubMed
Abstract

Insights

Pathogenic bacteria like Mycobacterium use polyphosphate (polyP) to evade immune cells. Researchers identified a polyP-sensing pathway in Dictyostelium discoideum, crucial for bacterial survival, with potential therapeutic implications for human macrophages.

Area of Science:

  • Cellular microbiology
  • Signal transduction
  • Host-pathogen interactions

Background:

  • Most bacteria are rapidly eliminated by phagocytosis within eukaryotic cells.
  • Certain pathogenic bacteria, including Mycobacterium species, survive phagocytosis by secreting polyphosphate (polyP).
  • Exogenous polyP inhibits the killing of bacteria by human macrophages and Dictyostelium discoideum.

Purpose of the Study:

  • To identify the key components of the polyphosphate (polyP) signal transduction pathway in Dictyostelium discoideum.
  • To investigate the role of this pathway in preventing the killing of ingested bacteria.
  • To explore the potential therapeutic applications of targeting this pathway in human macrophages.

Main Methods:

  • Genetic screening to identify components of the polyP signal transduction pathway in Dictyostelium discoideum.
  • Phagocytosis assays using wild-type and mutant Dictyostelium discoideum strains.
  • Comparative analysis of pathway component orthologs in human cells.

Main Results:

  • Key components of the polyP signal transduction pathway in Dictyostelium discoideum were identified.
  • In Dictyostelium discoideum cells lacking these components, polyP failed to inhibit the killing of ingested bacteria.
  • Orthologs of these pathway components exist in human cells.

Conclusions:

  • A novel polyP signal transduction pathway is essential for pathogenic bacteria to evade killing by Dictyostelium discoideum.
  • This pathway's conservation in humans suggests a potential therapeutic target for treating infections caused by intracellular pathogens.
  • Pharmacological inhibition of this pathway in human macrophages could enhance their ability to eliminate pathogens like Mycobacterium tuberculosis.
Keywords:
Dictyosteliumbacterial survivalphagocytosispolyphosphate

More Related Videos

Genetic Engineering of Dictyostelium discoideum Cells Based on Selection and Growth on Bacteria06:08

Genetic Engineering of Dictyostelium discoideum Cells Based on Selection and Growth on Bacteria

Published on: January 25, 2019

13.0K
Investigating the Function of Coronin A in the Early Starvation Response of Dictyostelium discoideum by Aggregation Assays07:48

Investigating the Function of Coronin A in the Early Starvation Response of Dictyostelium discoideum by Aggregation Assays

Published on: June 18, 2016

7.3K

Related Concept Videos

Other Stress Responses in Bacteria01:30

Other Stress Responses in Bacteria

Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
30
Stringent Response in E. coli01:23

Stringent Response in E. coli

Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
28
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a...
3.6K
Cell Inclusions01:27

Cell Inclusions

Prokaryotic cells possess a variety of inclusions that play crucial roles in nutrient storage, metabolic processes, and environmental adaptation. These structures enable bacteria to thrive under fluctuating environmental conditions by storing essential resources and optimizing their metabolic efficiency.Carbon Storage: Poly-β-Hydroxybutyric Acid and Glycogen GranulesBacteria frequently store excess carbon in specialized granules. Poly-β-hydroxybutyric acid (PHB) granules are lipid...
34
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...
3.4K
IP3/DAG Signaling Pathway01:11

IP3/DAG Signaling Pathway

Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the  phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...
12.2K