Intrinsically disordered proteins display no preference for chaperone binding in vivo

Area of Science:

• Proteomics
• Biochemistry
• Molecular Biology

Background:

• Intrinsically disordered proteins (IDPs) exhibit high sensitivity to proteolysis in vitro, yet avoid enhanced degradation in vivo.
• Chaperone association is hypothesized to protect IDPs from cellular proteases.
• Understanding IDP stability and function in vivo is crucial for cell biology.

Purpose of the Study:

• To investigate the relationship between predicted protein disorder and chaperone binding.
• To determine if chaperone binding protects intrinsically disordered proteins from degradation.
• To elucidate the role of chaperones in the cellular context of IDPs.

Main Methods:

• Analysis of pairwise interaction data from high-throughput studies.
• Utilized IUPred algorithm for predicting protein disorder.
• Correlated predicted disorder with chaperone binding propensity across species (E. coli, S. cerevisiae, metazoa).

Main Results:

• A negative correlation was observed between predicted disorder and chaperone binding in E. coli, S. cerevisiae, and metazoa.
• Disorder positively correlates with general partner binding, making the negative correlation with chaperones more significant.
• Chaperone binding preference is higher for proteins with at least one Pfam domain, suggesting a role in folding globular proteins.

Conclusions:

• Chaperone binding does not primarily protect intrinsically disordered proteins (IDPs) from degradation.
• Chaperone binding may facilitate the assembly of IDPs with their interaction partners, rather than aiding in folding.
• IDPs that bind chaperones also show a propensity to bind other proteins, supporting a role in complex formation.