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Major phosphorylation of SF1 on adjacent Ser‐Pro motifs enhances interaction with U2AF 65
Author(s) -
Manceau Valérie,
Swenson Matthew,
Le Caer JeanPierre,
Sobel André,
Kielkopf Clara L.,
Maucuer Alexandre
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.05091.x
Subject(s) - phosphorylation , rna splicing , spliceosome , rna binding protein , microbiology and biotechnology , alternative splicing , biology , splicing factor , intron , rna , computational biology , genetics , gene , messenger rna
Protein phosphorylation ensures the accurate and controlled expression of the genome, for instance by regulating the activities of pre‐mRNA splicing factors. Here we report that splicing factor 1 (SF1), which is involved in an early step of intronic sequence recognition, is highly phosphorylated in mammalian cells on two serines within an SPSP motif at the junction between its U2AF 65 and RNA binding domains. We show that SF1 interacts in vitro with the protein kinase KIS, which possesses a ‘U2AF homology motif’ (UHM) domain. The UHM domain of KIS is required for KIS and SF1 to interact, and for KIS to efficiently phosphorylate SF1 on the SPSP motif. Importantly, SPSP phosphorylation by KIS increases binding of SF1 to U2AF 65 , and enhances formation of the ternary SF1–U2AF 65 –RNA complex. These results further suggest that this phosphorylation event has an important role for the function of SF1, and possibly for the structural rearrangements associated with spliceosome assembly and function.