Publication Date:
2014-12-24
Description:
Intrinsically disordered proteins play important roles in cell signalling, transcription, translation and cell cycle regulation. Although they lack stable tertiary structure, many intrinsically disordered proteins undergo disorder-to-order transitions upon binding to partners. Similarly, several folded proteins use regulated order-to-disorder transitions to mediate biological function. In principle, the function of intrinsically disordered proteins may be controlled by post-translational modifications that lead to structural changes such as folding, although this has not been observed. Here we show that multisite phosphorylation induces folding of the intrinsically disordered 4E-BP2, the major neural isoform of the family of three mammalian proteins that bind eIF4E and suppress cap-dependent translation initiation. In its non-phosphorylated state, 4E-BP2 interacts tightly with eIF4E using both a canonical YXXXXLPhi motif (starting at Y54) that undergoes a disorder-to-helix transition upon binding and a dynamic secondary binding site. We demonstrate that phosphorylation at T37 and T46 induces folding of residues P18-R62 of 4E-BP2 into a four-stranded beta-domain that sequesters the helical YXXXXLPhi motif into a partly buried beta-strand, blocking its accessibility to eIF4E. The folded state of pT37pT46 4E-BP2 is weakly stable, decreasing affinity by 100-fold and leading to an order-to-disorder transition upon binding to eIF4E, whereas fully phosphorylated 4E-BP2 is more stable, decreasing affinity by a factor of approximately 4,000. These results highlight stabilization of a phosphorylation-induced fold as the essential mechanism for phospho-regulation of the 4E-BP:eIF4E interaction and exemplify a new mode of biological regulation mediated by intrinsically disordered proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bah, Alaji -- Vernon, Robert M -- Siddiqui, Zeba -- Krzeminski, Mickael -- Muhandiram, Ranjith -- Zhao, Charlie -- Sonenberg, Nahum -- Kay, Lewis E -- Forman-Kay, Julie D -- MOP-114985/Canadian Institutes of Health Research/Canada -- MOP-119579/Canadian Institutes of Health Research/Canada -- England -- Nature. 2015 Mar 5;519(7541):106-9. doi: 10.1038/nature13999. Epub 2014 Dec 22.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada. ; Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada. ; 1] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada [2] Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada. ; Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada. ; 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada [3] Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada [4] Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25533957" target="_blank"〉PubMed〈/a〉
Keywords:
Binding Sites
;
Eukaryotic Initiation Factor-4E/*chemistry/*metabolism
;
Eukaryotic Initiation Factors/*chemistry/*metabolism
;
Humans
;
Intrinsically Disordered Proteins/*chemistry/*metabolism
;
Models, Molecular
;
Nuclear Magnetic Resonance, Biomolecular
;
Phosphorylation
;
Protein Binding
;
*Protein Folding
;
Protein Structure, Secondary
;
Signal Transduction
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
