Tim Chaperones
Tim Chaperones - Related Videos
03:00
Molecular Chaperones and Protein Folding
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2020
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...
08:17
Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS
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Cited by 10 •
2017
The low-energy water-accommodated fraction (LEWAF) of crude oil is a challenging system to analyze, because over time, this complex mixture undergoes chemical transformations. This protocol illustrates methods for the preparation of the LEWAF sample and for performing photo-irradiation and chemical analysis by trapped ion mobility spectrometry–FT-ICR MS.
02:38
Assessing Bacterial Chaperone Activity via Thermal Unfolding of a Model Protein
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2025
Source: Dahl, J. et al. Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo. J. Vis. Exp. (2016)This video demonstrates a fluorescence spectrophotometer-based assay to evaluate chaperone activity on a substrate protein under acid and heat stress. It outlines the steps for monitoring substrate unfolding and aggregation through light scattering, comparing conditions with and without the chaperone.
08:32
Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo
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2016
This study describes biophysical, biochemical and molecular techniques to characterize the chaperone activity of Escherichia coli HdeB under acidic pH conditions. These methods have been successfully applied for other acid-protective chaperones such as HdeA and can be modified to work for other chaperones and stress conditions.
02:46
Assessing the Protective Role of an Acid-Activated Chaperone in E. coli Under Acid Stress
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2025
Source: Dahl, J., et al. Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo. J. Vis. Exp. (2016)This video demonstrates the use of recombinant E. coli cultures to evaluate the protective effect of an acid-activated chaperone during acid stress. Bacterial growth monitoring reveals enhanced survival in chaperone-expressing cultures compared to controls, highlighting the role of chaperones in protein stabilization under stress conditions.
FAQs
Hydrophobic regions that will later reside in the inner membrane are poorly suited to the aqueous intermembrane space. Tim chaperones bind these exposed regions after the precursors cross the outer membrane, keeping them soluble and reducing aggregation. This temporary protection allows the proteins to remain competent for delivery to the machinery that inserts them into the inner membrane.
Tim9–Tim10 complexes recognize exposed hydrophobic portions of incoming carrier proteins and shield them during transit. Their role is not simply to hold the precursors, but to coordinate protection with delivery toward the TIM22 translocase. This coupling helps preserve precursor integrity while directing proteins to the correct membrane-insertion pathway.
TIM22 provides the destination where chaperone-bound carrier proteins can be inserted into the inner mitochondrial membrane. Delivery therefore links recognition in the intermembrane space with assembly in the membrane itself. If this handoff is disrupted, transporters and other essential membrane proteins may not be incorporated properly, weakening mitochondrial biogenesis.
The pathway begins with precursor synthesis in the cytosol. The hydrophobic protein then passes through the mitochondrial outer membrane, encounters Tim chaperone complexes in the intermembrane space, and is guided toward TIM22. Finally, the translocase inserts the carrier into the inner membrane. This sequence coordinates cytosolic production, compartmental protection, targeting, and membrane assembly.
By enabling carrier proteins and other essential membrane proteins to reach the inner membrane, Tim chaperones support construction and maintenance of functional mitochondria. Their activity connects protein import with membrane-protein assembly rather than treating these as separate events. Studying this connection clarifies how mitochondria acquire components needed for their ongoing biological functions.
Investigating Tim chaperones can show how failures in mitochondrial protein import affect proteostasis, the controlled handling of proteins within the organelle. Defective guidance or delivery may interfere with inner-membrane assembly and mitochondrial biogenesis. These molecular links provide a framework for studying disorders associated with impaired mitochondrial protein import and for interpreting their underlying cellular defects.