Heat‐stable translational inhibitor from rabbit reticulocyte lysates

FEBS Letters

Mendez, Enrique¹  Gaitero, Fuencisla²  Haro, Cesar² 

[1] Servicio de Endocrinologia, Centra Ramón y Cajal, 28034 Madrid, Spain;Centra de Biologia Molecular (CSIC-UAM), Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain

关键词: Polypeptide chain initiation;    Translational inhibition;    eIF-2α kinase;    HCI activation;    eIF-2;    eukaryotic polypeptide chain-initiation factor 2;    Met-tRNAi;    eukaryotic initiator methionyl-tRNA;    HCI;    hemecontrolled translational inhibitor (an eIF-2α kinase);    proHCI;    the proinhibitor (inactive) form of HCI;    HS;    heat-stable translational inhibitor from rabbit reticulocyte lysates;    DTT;    dithiothreitol;    G6P;    glucose 6-phosphate;    FDP;    fructose 1;    6-bisphosphate;    NEM;    N-ethylmaleimide;    GSSG;    oxidized glutathione;    GEF;    guanine nucleotide exchange factor;    PL;    phospholipid;    H+-NMR;    proton nuclear magnetic resonance;   

DOI  :  10.1016/0014-5793(89)81556-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have purified to apparent homogeneity a heat-stable (HS) factor from the postribosomal supernatant of rabbit reticulocyte lysates [(1988) FEBS Lett. 236, 479-483]. HS inhibits translation in hemin-supplemented lysates and induces phosphorylation of the α-subunit of the eukaryotic initiation factor 2 as does hemin deficiency. The translational inhibition produced by addition of HS to hemin-containing reticulocyte lysates and the accompanying phosphorylation of the eIF-2α subunit can be prevented or reversed by NADPH generators including glucose 6-phosphate, NADPH itself, and also by dithiols, e.g., dithiothreitol, but not by fructose 1,6-bisphosphate or by monothiols, e.g., 2-mercaptoethanol. When added to crude preparations of the proinhibitor form (proHCI) of the heme-controlled translational inhibitor (HCI), HS produces a pronounced increase of the HCI to proHCI ratio. It appeared possible that HS might be oxidized gluatathione (GSSG) but this is not the case, for HS is not a substrate for highly purified glutathione reductase from rabbit erytrocytes. The spectral analysis of highly purified HS is consistent with the idea that HS could be a nucleotide derivative.

【 授权许可】

Unknown