Intrinsically disordered proteins display no preference for chaperone binding in vivo.

TitleIntrinsically disordered proteins display no preference for chaperone binding in vivo.
Publication TypeJournal Article
Year of Publication2008
AuthorsHegyi, H., and P. Tompa
JournalPLoS Comput Biol
Volume4
Issue3
Paginatione1000017
Date Published2008 Mar
Type of Articleidp
ISSN1553-7358
KeywordsBinding Sites, Computer Simulation, Models, Chemical, Models, Molecular, Molecular Chaperones, Protein Binding, Protein Interaction Mapping, Sequence Analysis, Protein
Abstract

Intrinsically disordered/unstructured proteins (IDPs) are extremely sensitive to proteolysis in vitro, but show no enhanced degradation rates in vivo. Their existence and functioning may be explained if IDPs are preferentially associated with chaperones in the cell, which may offer protection against degradation by proteases. To test this inference, we took pairwise interaction data from high-throughput interaction studies and analyzed to see if predicted disorder correlates with the tendency of chaperone binding by proteins. Our major finding is that disorder predicted by the IUPred algorithm actually shows negative correlation with chaperone binding in E. coli, S. cerevisiae, and metazoa species. Since predicted disorder positively correlates with the tendency of partner binding in the interactome, the difference between the disorder of chaperone-binding and non-binding proteins is even more pronounced if normalized to their overall tendency to be involved in pairwise protein-protein interactions. We argue that chaperone binding is primarily required for folding of globular proteins, as reflected in an increased preference for chaperones of proteins in which at least one Pfam domain exists. In terms of the functional consequences of chaperone binding of mostly disordered proteins, we suggest that its primary reason is not the assistance of folding, but promotion of assembly with partners. In support of this conclusion, we show that IDPs that bind chaperones also tend to bind other proteins.

DOI10.1371/journal.pcbi.1000017
Alternate JournalPLoS Comput. Biol.
PubMed ID18369417
PubMed Central IDPMC2265518