Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Catalysis
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HeLa Cells
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Humans
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Nucleocytoplasmic Transport Proteins / genetics
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Nucleocytoplasmic Transport Proteins / metabolism*
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Phosphorylation
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Protein Binding
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RNA Splicing*
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RNA Transport*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism*
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Ribonucleoproteins / genetics
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Ribonucleoproteins / metabolism
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Serine-Arginine Splicing Factors
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Substrate Specificity
Substances
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NXF1 protein, human
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Nuclear Proteins
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Nucleocytoplasmic Transport Proteins
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RNA, Messenger
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RNA-Binding Proteins
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Ribonucleoproteins
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messenger ribonucleoprotein
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Serine-Arginine Splicing Factors