A molecular link between SR protein dephosphorylation and mRNA export.
In metazoans, multiple RNA-binding proteins, including the shuttling serine/arginine-rich (SR)-splicing factors, function as adapters for mRNA nuclear export by interacting with the export receptor TAP/nuclear export factor 1 (NXF1). Yet, it is unclear how interactions between adapters and TAP are regulated. Here, we demonstrate that the SR proteins 9G8 and ... ASF/SF2 exhibit higher affinity for TAP/NXF1 when hypophosphorylated. 9G8 is recruited to the pre-mRNA in a hyperphosphorylated form but becomes hypophosphorylated during splicing both in vivo and in vitro. TAP preferentially binds spliced mRNA-protein complexes compared with pre-mRNA-protein complexes. Thus, the phosphorylation state of the SR protein adapters may underlie the selectivity of TAP-mediated export of spliced mRNA.
Mesh Terms:
Catalysis, HeLa Cells, Humans, Nuclear Proteins, Nucleocytoplasmic Transport Proteins, Phosphorylation, Protein Binding, RNA Splicing, RNA Transport, RNA, Messenger, RNA-Binding Proteins, Ribonucleoproteins, Substrate Specificity
Catalysis, HeLa Cells, Humans, Nuclear Proteins, Nucleocytoplasmic Transport Proteins, Phosphorylation, Protein Binding, RNA Splicing, RNA Transport, RNA, Messenger, RNA-Binding Proteins, Ribonucleoproteins, Substrate Specificity
Proc. Natl. Acad. Sci. U.S.A.
Date: Jun. 29, 2004
PubMed ID: 15210956
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