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Updated: May 10, 2026
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Using Caenorhabditis elegans to Screen for Tissue-Specific Chaperone Interactions
Published on: June 7, 2020
Chaperone-interacting TPR proteins in Caenorhabditis elegans
Veronika Haslbeck1, Julia M Eckl, Christoph J O Kaiser
1Center for Integrated Protein Science Munich and Department of Chemistry, Technische Universität München, 85747 Garching, Germany.
Journal of Molecular Biology
|June 4, 2013
Summary
Researchers screened the C. elegans proteome for proteins interacting with molecular chaperones Hsc70/Hsp70 and Hsp90. They identified specific TPR proteins that bind these chaperones, revealing insights into chaperone-cofactor interactions.
Area of Science:
- Molecular Biology
- Cell Biology
- Genomics
Background:
- Molecular chaperones heat shock cognate 70 (Hsc70/Hsp70) and heat shock protein 90 (Hsp90) interact with tetratricopeptide repeat (TPR)-containing proteins.
- These TPR proteins act as cofactors, influencing chaperone activity and substrate binding through conserved C-terminal motifs (e.g., IEEVD, MEEVD).
- Higher eukaryotes possess numerous TPR proteins, but the extent of their interaction with Hsc70/Hsp90 remains largely uncharacterized.
Purpose of the Study:
- To systematically screen the Caenorhabditis elegans proteome for TPR-domain-containing proteins that interact with Hsc70 and Hsp90.
- To identify and rank potential TPR-chaperone interactions based on sequence similarity to known interacting TPRs.
- To investigate the binding affinities and in vivo localization of novel TPR-chaperone interactions.
Main Methods:
- Proteome-wide screening of C. elegans TPR proteins for potential Hsc70/Hsp90 interaction.
- Ranking of candidate TPR proteins based on similarity to known chaperone-binding TPR motifs.
- Biochemical assays to determine binding affinities (e.g., low micromolar) of selected TPR proteins (C34B2.5, ZK370.8) to Hsc70 and Hsp90.
- Mutational analysis of EEVD-binding residues to confirm interaction disruption.
- In vivo localization studies using microscopy to determine the cellular distribution of C34B2.5 and ZK370.8.
Main Results:
- Identified numerous TPR proteins in C. elegans, many lacking yeast homologs but conserved in higher eukaryotes.
- Highly ranked uncharacterized proteins (C33H5.8, C34B2.5, ZK370.8) show potential homology to human RPAP3, TTC1, and TOM70.
- C34B2.5 and ZK370.8 exhibit low micromolar binding affinity for both Hsc70 and Hsp90, with binding dependent on EEVD-motif interactions.
- ZK370.8 localizes to mitochondria, and C34B2.5 colocalizes with Hsc70 in intestinal cells.
- A protein with non-conserved EEVD-binding residues (F52H3.5) showed no chaperone binding, suggesting limited TPR-chaperone interactions (~15 in C. elegans).
Conclusions:
- C. elegans encodes a significant repertoire of TPR proteins, with a subset specifically interacting with Hsc70/Hsp90.
- Novel TPR proteins like C34B2.5 and ZK370.8 are validated Hsc70/Hsp90 binders, demonstrating conserved chaperone-cofactor interactions.
- The study suggests that most TPR proteins in C. elegans may interact with ligands other than Hsc70/Hsp90, highlighting functional diversification within the TPR domain superfamily.
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