AI Article Synopsis
- The GroEL/ES chaperonin system is crucial for properly folding many proteins, but the process of how these proteins are encapsulated is not well understood.
- Using advanced cryo-electron microscopy, researchers studied a modified version of GroEL that was stuck in an intermediate stage of this process.
- Their findings revealed that the typical symmetrical arrangement of GroEL subunits changes to allow GroES and an incompletely folded protein (RuBisCO) to bind simultaneously, highlighting the dynamic nature of protein folding and release.
Article Abstract
The GroEL/ES chaperonin system is required for the assisted folding of many proteins. How these substrate proteins are encapsulated within the GroEL-GroES cavity is poorly understood. Using symmetry-free, single-particle cryo-electron microscopy, we have characterized a chemically modified mutant of GroEL (EL43Py) that is trapped at a normally transient stage of substrate protein encapsulation. We show that the symmetric pattern of the GroEL subunits is broken as the GroEL cis-ring apical domains reorient to accommodate the simultaneous binding of GroES and an incompletely folded substrate protein (RuBisCO). The collapsed RuBisCO folding intermediate binds to the lower segment of two apical domains, as well as to the normally unstructured GroEL C-terminal tails. A comparative structural analysis suggests that the allosteric transitions leading to substrate protein release and folding involve concerted shifts of GroES and the GroEL apical domains and C-terminal tails.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3695626 | PMC |
| http://dx.doi.org/10.1016/j.cell.2013.04.052 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Serine phosphorylation facilitates protein degradation by the human mitochondrial ClpXP protease.
Proc Natl Acad Sci U S A
February 2025
Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada.
ClpXP is a two-component mitochondrial matrix protease. The caseinolytic mitochondrial matrix peptidase chaperone subunit X (ClpX) recognizes and translocates protein substrates into the degradation chamber of the caseinolytic protease P (ClpP) for proteolysis. ClpXP degrades damaged respiratory chain proteins and is necessary for cancer cell survival.
View Article and Find Full Text PDFHsp90, DnaK, and ClpB collaborate in protein reactivation.
Proc Natl Acad Sci U S A
February 2025
Laboratory of Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892.
Hsp70, Hsp90, and ClpB/Hsp100 are molecular chaperones that help regulate proteostasis. Bacterial and yeast Hsp70s and their cochaperones function synergistically with Hsp90s to reactivate inactive and aggregated proteins by a mechanism that requires a direct interaction between Hsp90 and Hsp70 both in vitro and in vivo. and yeast Hsp70s also collaborate in bichaperone systems with ClpB and Hsp104, respectively, to disaggregate and reactivate aggregated proteins and amyloids such as prions.
View Article and Find Full Text PDFSmall Molecule Modulators of AMP-Activated Protein Kinase (AMPK) Activity and Their Potential in Cancer Therapy.
J Med Chem
January 2025
Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 East Montview Boulevard, Aurora, Colorado 80045, United States.
AMP-activated protein kinase (AMPK) is a central mediator of cellular metabolism and is activated in direct response to low ATP levels. Activated AMPK inhibits anabolic pathways and promotes catabolic activities that generate ATP through the phosphorylation of multiple target substrates. AMPK is a therapeutic target for activation in several chronic metabolic diseases, and there is increasing interest in targeting AMPK activity in cancer where it can act as a tumor suppressor or conversely it can support cancer cell survival.
View Article and Find Full Text PDFTetraspanins 10 and 15 support Venezuelan equine encephalitis virus replication in astrocytoma cells.
Mol Biol Cell
January 2025
Institute for Biochemistry & Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany.
Tetraspanins (Tspans) are transmembrane proteins that coordinate life cycle steps of viruses from distinct families. Here, we identify the human Tspan10 and Tspan15, both members of the TspanC8 subfamily, as replication factors for alphavirus Venezuelan equine encephalitis virus (VEEV) in astrocytoma cells. Pharmacological inhibition and siRNA-mediated silencing of TspanC8 interactor a disintegrin and metalloproteinase 10 (ADAM10) reduced VEEV infection.
View Article and Find Full Text PDFStructural analysis of extracellular ATP-independent chaperones of streptococcal species and protein substrate interactions.
mSphere
January 2025
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Unlabelled: During infection, bacterial pathogens rely on secreted virulence factors to manipulate the host cell. However, in gram-positive bacteria, the molecular mechanisms underlying the folding and activity of these virulence factors after membrane translocation are not clear. Here, we solved the protein structures of two secreted parvulin and two secreted cyclophilin-like peptidyl-prolyl isomerase (PPIase) ATP-independent chaperones found in gram-positive streptococcal species.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!