Proline-rich sequence recognition I: Marking GYF and WW domain assembly sites in early spliceosomal complexes
M. Kofler, M. Schümann, C. Merz, D. Kosslick, A. Schlundt, A. Tannert,. M. Schaefer, R. Lührmann, E. Krause, C. Freund – 2009
Proline-rich sequences (PRS) and their recognition domains have emerged as transposable protein interaction modules during eukaryotic evolution. They are especially abundant in proteins associated with pre-mRNA splicing and likely assist in the formation of the spliceosome by binding to GYF and WW domains. Here we profile PRS-mediated interactions of the CD2BP2/52K GYF domain by a site-specific peptide inhibitor and stable isotope labeling/mass spectrometry analysis. Several PRS hubs with multiple proline-rich motifs exist that can recruit GYF and/or WW domains. Saturating the PRS sites by an isolated GYF domain inhibited splicing at the level of A complex formation. The interactions mediated by PRS are therefore important to the early phases of spliceosomal assembly.