Structure of Phosphorylated SF1 Bound to U2AF(65) in an Essential Splicing Factor Complex.
Wang, W., Maucuer, A., Gupta, A., Manceau, V., Thickman, K.R., Bauer, W.J., Kennedy, S.D., Wedekind, J.E., Green, M.R., Kielkopf, C.L.(2013) Structure 21: 197-208
- PubMed: 23273425 
- DOI: https://doi.org/10.1016/j.str.2012.10.020
- Primary Citation of Related Structures:  
4FXW, 4FXX - PubMed Abstract: 
The essential splicing factors U2AF⁶⁵ and SF1 cooperatively bind consensus sequences at the 3' end of introns. Phosphorylation of SF1 on a highly conserved "SPSP" motif enhances its interaction with U2AF⁶⁵ and the pre-mRNA. Here, we reveal that phosphorylation induces essential conformational changes in SF1 and in the SF1/U2AF⁶⁵/3' splice site complex. Crystal structures of the phosphorylated (P)SF1 domain bound to the C-terminal domain of U2AF⁶⁵ at 2.29 Å resolution and of the unphosphorylated SF1 domain at 2.48 Å resolution demonstrate that phosphorylation induces a disorder-to-order transition within a previously unknown SF1/U2AF⁶⁵ interface. We find by small-angle X-ray scattering that the local folding of the SPSP motif transduces into global conformational changes in the nearly full-length (P)SF1/U2AF⁶⁵/3' splice site assembly. We further determine that SPSP phosphorylation and the SF1/U2AF⁶⁵ interface are essential in vivo. These results offer a structural prototype for phosphorylation-dependent control of pre-mRNA splicing factors.
Organizational Affiliation: 
Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.