Related Experiment Video
Updated: May 4, 2026
08:51
Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling
Published on: June 25, 2015
8.7K
The Prc and RseP proteases control bacterial cell-surface signalling activity.
Karlijn C Bastiaansen1, Aurelia Ibañez, Juan L Ramos
1Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain; Section of Molecular Microbiology, Department of Molecular Cell Biology, VU University Amsterdam, Amsterdam, The Netherlands.
Environmental Microbiology
|December 31, 2013
Summary
Extracytoplasmic function sigma factors regulate bacterial environmental responses. In Pseudomonas putida, a unique proteolytic pathway involving Prc and RseP proteases activates the Iut ECF sigma factor.
Area of Science:
- Bacteriology
- Molecular Biology
- Biochemistry
Background:
- Extracytoplasmic function (ECF) sigma factors are crucial for bacterial environmental adaptation.
- Cell-surface signaling (CSS) regulates ECF sigma factor activity in Gram-negative bacteria via outer membrane receptors and anti-sigma factors.
Purpose of the Study:
- To elucidate the molecular mechanism of CSS regulation using the unique Iut system in Pseudomonas putida.
- To investigate the role of proteases in ECF sigma factor activation.
Main Methods:
- Characterization of the Pseudomonas putida Iut system, a hybrid ECF sigma and anti-sigma factor.
- Analysis of the proteolytic pathway involving Prc and RseP proteases.
- Demonstration of protease roles in classical CSS systems.
Main Results:
- The Iut ECF sigma factor regulates aerobactin response under iron deficiency.
- Activation involves sequential proteolysis: Prc removes the anti-sigma domain, and RseP removes the transmembrane domain.
- Prc and RseP proteases are essential for activating the ECF sigma factor's transcriptional function.
Conclusions:
- A novel proteolytic pathway activates the Iut ECF sigma factor in Pseudomonas putida.
- This mechanism highlights the conserved role of proteases in regulating ECF sigma factors via CSS.
- Findings provide insights into bacterial stress response and virulence regulation.
More Related Videos
Related Concept Videos
01:22Amplifying Signals via Enzymatic Cascade
15.3K
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
15.3K
01:34Directing Proteins to the Rough Endoplasmic Reticulum
12.0K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
12.0K
01:12GPCR Desensitization
6.1K
G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...
6.1K
01:09GPCRs Regulate Adenylyl Cylase Activity
6.9K
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...
6.9K
02:58Regulated Protein Degradation
6.6K
It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
6.6K
01:11IP3/DAG Signaling Pathway
12.5K
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...
12.5K