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Updated: Jul 5, 2026

Monitoring eIF4F Assembly by Measuring eIF4E-eIF4G Interaction in Live Cells
Published on: May 1, 2020
The splicing factor SF2/ASF regulates translation initiation by enhancing phosphorylation of 4E-BP1
Gracjan Michlewski1, Jeremy R Sanford, Javier F Cáceres
1Medical Research Council Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.
Abstract:
The SR protein SF2/ASF has been initially characterized as a splicing factor but has also been shown to mediate postsplicing activities such as mRNA export and translation. Here we demonstrate that SF2/ASF promotes translation initiation of bound mRNAs and that this activity requires the presence of the cytoplasmic cap-binding protein eIF4E. SF2/ASF promotes translation initiation by suppressing the activity of 4E-BP, a competitive inhibitor of cap-dependent translation. This activity is mediated by interactions of SF2/ASF with both mTOR and the phosphatase PP2A, two key regulators of 4E-BP phosphorylation. These findings suggest the model whereby SF2/ASF functions as an adaptor protein to recruit the signaling molecules responsible for regulation of cap-dependent translation of specific mRNAs. Taken together, these data suggest a novel mechanism for the activation of translation initiation of a subset of mRNAs bound by the shuttling protein SF2/ASF.
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