mTORC1 and CK2 coordinate ternary and eIF4F complex assembly

Valentina Gandin (1, 2, 3, 4) , Laia Masvidal (5) , Marie Cargnello (1, 2, 3, 4) , Laszlo Gyenis (6) , Shannon Mclaughlan (1, 2, 3, 4) , Yutian Cai (1, 3) , Clara Tenkerian (1, 6) , Masahiro Morita (3) , Preetika Balanathan (7) , Olivier Jean-Jean (8) , Vuk Stambolic (9) , Matthias Trost (10) , Luc Furic (7) , Louise Larose (11) , Antonis E. Koromilas (1, 4, 6) , Katsura Asano (12) , David Litchfield (6) , Ola Larsson (5) , Ivan Topisirovic (1, 2, 3, 4)

1 Lady Davis Institute for Medical Research [Montréal]
2 Department of Oncology [Montréal]
3 Department of Biochemistry [Montréal]
4 Dpt of Experimental Medicine [Montreal]
5 Science for Life Laboratory [Solna]
6 Dpt of Biochemistry and Oncology [Ontario]
7 Cancer Program - Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology,
8 TE - Traduction eucaryote
9 University of Toronto, Princess Margaret Cancer Centre
10 MRC Protein Phosphorylation and Ubiquitylation Unit
11 Polypeptide Laboratory
12 Division of Biology, Kansas State University

Ternary complex (TC) and eIF4F complex assembly are the two major rate-limiting steps in translation initiation regulated by eIF2α phosphorylation and the mTOR/4E-BP pathway, respectively. How TC and eIF4F assembly are coordinated, however, remains largely unknown. We show that mTOR suppresses translation of mRNAs activated under short-term stress wherein TC recycling is attenuated by eIF2α phosphorylation. During acute nutrient or growth factor stimulation, mTORC1 induces eIF2β phosphorylation and recruitment of NCK1 to eIF2, decreases eIF2α phosphorylation and bolsters TC recycling. Accordingly, eIF2β mediates the effect of mTORC1 on protein synthesis and proliferation. In addition, we demonstrate a formerly undocumented role for CK2 in regulation of translation initiation, whereby CK2 stimulates phosphorylation of eIF2β and simultaneously bolsters eIF4F complex assembly via the mTORC1/4E-BP pathway. These findings imply a previously unrecognized mode of translation regulation, whereby mTORC1 and CK2 coordinate TC and eIF4F complex assembly to stimulate cell proliferation.

Keywords: Cell biology; Biological sciences; Biochemistry

Domains: Biochemistry, Molecular Biology

Valentina Gandin, Laia Masvidal, Marie Cargnello, Laszlo Gyenis, Shannon Mclaughlan, et al.. mTORC1 and CK2 coordinate ternary and eIF4F complex assembly. Nature Communications, 2016, 7, pp.11127. ⟨10.1038/ncomms11127⟩. ⟨hal-01299782⟩