Related Experiment Video
Updated: Jun 10, 2025
11:33
Monitoring the Assembly of a Secreted Bacterial Virulence Factor Using Site-specific Crosslinking
Published on: December 17, 2013
6.1K
Advanced glycation end-product crosslinking activates a type VI secretion system phospholipase effector protein
Steven J Jensen1, Bonnie J Cuthbert2, Fernando Garza-Sánchez1
1Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, 93106, USA.
Nature Communications
|October 11, 2024
Summary
Advanced glycation end-products (AGE) stabilize bacterial phospholipase structure by crosslinking protein domains. This AGE crosslinking, mediated by methylglyoxal, activates antibacterial function and may stabilize other proteins.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Advanced glycation end-products (AGE) are linked to various diseases and arise from reactive dicarbonyl compounds.
- Glycation is a metabolic byproduct, typically considered protein damage.
Purpose of the Study:
- To investigate the role of AGE crosslinking in activating bacterial phospholipase effector proteins.
- To explore AGE crosslinking as a potential protein stabilization mechanism.
Main Methods:
- Investigated the type VI secretion system of Enterobacter cloacae.
- Utilized site-directed mutagenesis to examine specific arginine-lysine crosslinking.
- Restored enzyme function using engineered disulfide bonds in vitro.
Main Results:
- AGE crosslinking of a specific arginine-lysine pair stabilizes the phospholipase domain.
- Mutations disrupting this crosslinking abolish phospholipase activity.
- Engineered disulfide bonds restored in vitro enzyme function.
Conclusions:
- AGE crosslinking acts as a post-translational modification to stabilize phospholipase structure.
- This glycation-mediated stabilization mechanism may be broadly applicable to other proteins, especially in the cytoplasm.
- Methylglyoxal's ubiquity suggests glycation is a general strategy for protein stabilization.
Related Concept Videos
01:25cAMP-dependent Protein Kinase Pathways
6.2K
Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
6.2K
01:09GPCRs Regulate Adenylyl Cylase Activity
5.3K
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...
5.3K
01:05Insulin Secretory Vesicles
4.8K
Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
4.8K
01:11IP3/DAG Signaling Pathway
11.9K
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...
11.9K
01:17Gram-negative Bacterial Protein Secretion Systems
1
Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
1
01:16TGF - β Signaling Pathway
7.2K
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...
7.2K