Related Experiment Video
Updated: Aug 10, 2026
07:18
Intracellular Refolding Assay
Published on: January 24, 2012
Endogenous extra-cellular heat shock protein 72: releasing signal(s) and function
1Department of Integrative Physiology, University of Colorado-Bouler, CO 80309-0354, USA. fleshner@colorado.edu
Summary
Acute stress triggers the release of extracellular heat shock protein 72 (eHsp72), acting as a danger signal. This eHsp72 enhances innate immunity during bacterial challenges, improving survival.
Area of Science:
- Physiology
- Immunology
- Molecular Biology
Background:
- The acute stress response involves physiological changes at multiple levels.
- Heat shock protein 72 (Hsp72) is a key cellular stress response protein.
- The role of extracellular Hsp72 (eHsp72) in acute stress is largely unknown.
Purpose of the Study:
- To hypothesize that eHsp72 release is a feature of the acute stress response.
- To propose eHsp72 functions as an endogenous danger signal for the immune system.
- To investigate the mechanism and immune function of eHsp72 during stress.
Main Methods:
- Review of existing literature on stress response and Hsp72.
- Hypothetical model development for eHsp72 release and function.
- Focus on alpha1-adrenergic receptor mediation and innate immunity facilitation.
Main Results:
- Acute stressors may induce eHsp72 release into circulation.
- eHsp72 release is potentially mediated by alpha1-adrenergic receptors.
- Elevated eHsp72 may enhance innate immune response to bacterial challenge.
Conclusions:
- eHsp72 release is a novel aspect of the acute stress response.
- eHsp72 acts as a crucial danger signal linking stress and immunity.
- This mechanism enhances host defense during combined stress and infection.
Related Concept Videos
03:00Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
01:37The Unfolded Protein Response
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
01:31Regulation of the Unfolded Protein Response
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
01:20The JAK-STAT Signaling Pathway
Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as SH2...
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...
01:30Other 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...