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In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells
Published on: September 2, 2019
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Bi-handed assembly chaperones regulate protein complex assembly through an intramolecular handover mechanism
Jingyi Wu1, Chun Wan1, Yuan Tian2
1Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
Science Advances
|September 12, 2025
Summary
Researchers discovered AAGAB, a novel bi-handed chaperone, that facilitates protein complex assembly. It uses distinct domains to bind subunits of the AP2 adaptor complex, revealing a new chaperone mechanism.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Protein complex assembly is crucial for cellular function.
- Dimeric intermediates are key for assembling larger protein complexes.
- The existence of "bi-handed" chaperones facilitating this step was unknown.
Purpose of the Study:
- To identify and characterize novel chaperones involved in protein complex assembly.
- To investigate the mechanism of bi-handed chaperones.
Main Methods:
- Protein binding assays
- Structural analysis
- Biochemical characterization of AAGAB and AP2 complex subunits
Main Results:
- AAGAB identified as a bi-handed chaperone.
- AAGAB binds the α and σ2 subunits of the AP2 adaptor complex via its CTD and GD domains, respectively.
- An intramolecular handover mechanism involving conformational maturation of the α:σ2 hemicomplex was elucidated.
Conclusions:
- AAGAB is the first identified member of a bi-handed chaperone family.
- A novel intramolecular handover mechanism is responsible for AAGAB's chaperone activity.
- This discovery provides new insights into the regulation of membrane trafficking and protein complex assembly.
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