U2AF-homology motif interactions are required for alternative splicing regulation by SPF45

Nat Struct Mol Biol. 2007 Jul;14(7):620-9. doi: 10.1038/nsmb1260. Epub 2007 Jun 24.


The U2AF-homology motif (UHM) mediates protein-protein interactions between factors involved in constitutive RNA splicing. Here we report that the splicing factor SPF45 regulates alternative splicing of the apoptosis regulatory gene FAS (also called CD95). The SPF45 UHM is necessary for this activity and binds UHM-ligand motifs (ULMs) present in the 3' splice site-recognizing factors U2AF65, SF1 and SF3b155. We describe a 2.1-A crystal structure of SPF45-UHM in complex with a ULM peptide from SF3b155. Features distinct from those of previously described UHM-ULM structures allowed the design of mutations in the SPF45 UHM that selectively impair binding to individual ULMs. Splicing assays using the ULM-selective SPF45 variants demonstrate that individual UHM-ULM interactions are required for FAS splicing regulation by SPF45 in vivo. Our data suggest that networks of UHM-ULM interactions are involved in regulating alternative splicing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing*
  • Amino Acid Motifs / genetics
  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Exons
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Nuclear Proteins / chemistry
  • Peptides / chemistry
  • Phosphoproteins / chemistry
  • Protein Conformation
  • Protein Interaction Mapping
  • RNA Splicing Factors
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Ribonucleoprotein, U2 Small Nuclear / chemistry
  • Ribonucleoproteins / chemistry
  • Splicing Factor U2AF
  • fas Receptor / genetics*


  • Nuclear Proteins
  • Peptides
  • Phosphoproteins
  • RBM17 protein, human
  • RNA Splicing Factors
  • RNA-Binding Proteins
  • Ribonucleoprotein, U2 Small Nuclear
  • Ribonucleoproteins
  • SF3B1 protein, human
  • Splicing Factor U2AF
  • U2AF2 protein, human
  • fas Receptor

Associated data

  • PDB/2PE8
  • PDB/2PEH