Regulation of apoptosis by an intrinsically disordered region of Bcl-xL.
Follis, A.V., Llambi, F., Kalkavan, H., Yao, Y., Phillips, A.H., Park, C.G., Marassi, F.M., Green, D.R., Kriwacki, R.W.(2018) Nat Chem Biol 14: 458-465
- PubMed: 29507390 
- DOI: https://doi.org/10.1038/s41589-018-0011-x
- Primary Citation of Related Structures:  
6BF2 - PubMed Abstract: 
Intrinsically disordered regions (IDRs) of proteins often regulate function upon post-translational modification (PTM) through interactions with folded domains. An IDR linking two α-helices (α1-α2) of the antiapoptotic protein Bcl-xL experiences several PTMs that reduce antiapoptotic activity. Here, we report that PTMs within the α1-α2 IDR promote its interaction with the folded core of Bcl-xL that inhibits the proapoptotic activity of two types of regulatory targets, BH3-only proteins and p53. This autoregulation utilizes an allosteric pathway whereby, in one direction, the IDR induces a direct displacement of p53 from Bcl-xL coupled to allosteric displacement of simultaneously bound BH3-only partners. This pathway operates in the opposite direction when the BH3-only protein PUMA binds to the BH3 binding groove of Bcl-xL, directly displacing other bound BH3-only proteins, and allosterically remodels the distal site, displacing p53. Our findings show how an IDR enhances functional versatility through PTM-dependent allosteric regulation of a folded protein domain.
Organizational Affiliation: 
Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.