Translational inhibition by eIF‐2‐phospholipid complex in mammalian cell‐free systems

FEBS Letters

de Haro, Cesar¹  Pelaez, Fernando¹ 

[1] Centro de Biología Molecular, Consejo Superior de Investigaciones Científicas and Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain

关键词: Protein synthesis;    Guanosine exchange factor;    trapping of;    Phospholipid effect;    Translation inhibition;    (Eukaryote);    eIF-2;    eukaryotic initiation factor 2;    GEF;    guanine nucleotide exchange factor;    PL;    phospholipid;    eIF-2(αP);    α-subunit-phosphorylated eIF-2;    PS;    phosphatidylserine;    PI;    phosphatidylinositol;    PE;    phosphatidylethanolamine;    DTT;    dithiothreitol;   

DOI  :  10.1016/0014-5793(89)80789-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The polypeptide chain initiation factor 2 (eIF-2) binds phospholipid (PL) and becomes a potent inhibitor of translation in hemin-supplemented reticulocyte lysates [De Haro et al. (1986) Proc. Natl. Acad. Sci. USA 83, 6711–6715]. This binding is independent of calcium ions and seems to be specific for phosphatidylinositol or phosphatidylserine; phosphatidic and arachidonic acids are inactive. Like α-subunit-phosphorylated eIF-2, eIF-2·PL traps GEF in a non-dissociable eIF-2·PL·GEF complex whereby GEF is no longer able to recycle. Initiation is inhibited when no free GEF is available. Translational inhibition by eIF-2·PL is rescued by equimolar amounts of eIF-2·GEF. On the basis of this stoichiometry, we have estimated that reticulocyte lysates contain about 60 pmol of GEF/ml (60 nM) eIF-2·PL also inhibits translation in cell-free mouse liver extracts and this inhibition is prevented by reticulocyte eIF-2·GEF suggesting that GEF also functions in liver. However, the eIF-2·PL complex does not affect translation in such non-mammalian eukaryotic systems as wheat germ and Drosophila embryos.

【 授权许可】

Unknown