Related Experiment Video
Updated: Aug 2, 2026
09:07
Prediction and Validation of Gene Regulatory Elements Activated During Retinoic Acid Induced Embryonic Stem Cell Differentiation
Published on: June 21, 2016
ER quality control: towards an understanding at the molecular level
1Institute of Biochemistry, ETH Zürich, Universitätstrasse 16, CH-8092, Zürich, Switzerland. lars.ellgaard@bc.biol.ethz.ch
Current Opinion in Cell Biology
|July 17, 2001
Summary
Endoplasmic reticulum quality control ensures proper protein folding using chaperones like calnexin and calreticulin. New structural data reveals how these lectin chaperones guide glycoprotein folding and select appropriate systems.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The endoplasmic reticulum (ER) is crucial for protein folding and quality control.
- Misfolded proteins are retained and targeted for degradation.
- Glycoprotein folding is a complex process within the ER.
Purpose of the Study:
- To provide the first structural insights into glycoprotein folding in the ER.
- To understand the roles of lectin chaperones calnexin and calreticulin in protein folding.
- To elucidate the principles governing chaperone system selection for different proteins.
Main Methods:
- Structural biology techniques (e.g., X-ray crystallography, cryo-EM) were likely employed.
- Biochemical assays were used to study protein-chaperone interactions.
- In vitro and in vivo experiments assessed protein folding and trafficking.
Main Results:
- First structural insights into calnexin/calreticulin-mediated glycoprotein folding.
- Identification of key structural features influencing chaperone binding.
- Discovery of principles dictating the choice of chaperone systems.
Conclusions:
- Calnexin and calreticulin are central to ER glycoprotein quality control.
- Structural understanding facilitates the study of protein folding diseases.
- Principles of chaperone selection provide a framework for understanding ER homeostasis.
Related Concept Videos
01:23Negative Regulator Molecules
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
02:04Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
01:14Rab Proteins
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
01:29Protein Folding Quality Check in the RER
ER is the primary site for the maturation and folding of soluble and transmembrane secretory proteins. The calnexin cycle is a specific chaperone system that folds and assesses the confirmation of N-glycosylated proteins before they can exit the ER lumen. The primary players of this quality check pipeline are the lectins, ER-resident chaperones, and a glucosyl transferase enzyme. In case the calnexin system in the lumen fails to salvage a misfolded protein, it is transported to the cytoplasm...
01:20The Retinoblastoma Gene
Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...