TY - JOUR
T1 - The effect of ethanol on polypeptide chain initiation in reticulocyte lysates. Inhibition of recycling of initiation factor eIF-2
AU - Cox, Sarah
AU - Proud, Christopher G.
N1 - Funding Information:
Acknowledgement-Sarah Cox was the recipient of a Studentshipf rom the Science and EngineeringR esearch Council (U.K.).
PY - 1988/5/15
Y1 - 1988/5/15
N2 - Using the reticulocyte cell-free system, we have investigated the mechanism by which ethanol inhibits the initiation of protein synthesis. Ethanol inhibited the formation of 40S-initiation complexes, and this effect correlated well with the inhibition by ethanol of overall peptide-chain initiation. Ethanol was a more potent inhibitor of translation at 37° than at 30°. The inhibition of peptide-chain initiation and 40S-initiation complex formation in reticulocyte lysates under other conditions is associated with increased phosphorylation of the α-subunit of protein synthesis initiation factor-2 (eIF-2α) and the inhibition of recycling of this factor. Recycling of eIF-2 is mediated by another protein factor GEF (= guanine nucleotide-exchange factor). The addition of ethanol to reticulocyte lysates led to increased phosphorylation of eIF-2α and to a decrease in the rate of exchange of guanine nucleotides bound to eIF-2. This second finding indicated that recycling of eIF-2 was impaired probably due to decreased availability of GEF. Using purified components it was found that ethanol inhibited the ability of GEF to stimulate eIF-2 and that this inhibition showed a similar temperature dependence to the effect of ethanol on overall protein synthesis. Taken together, these results suggest that ethanol leads to inhibition of peptide-chain initiation both through increased phosphorylation of eIF-2α and by directly inhibiting the productive interaction of eIF-2 and GEF.
AB - Using the reticulocyte cell-free system, we have investigated the mechanism by which ethanol inhibits the initiation of protein synthesis. Ethanol inhibited the formation of 40S-initiation complexes, and this effect correlated well with the inhibition by ethanol of overall peptide-chain initiation. Ethanol was a more potent inhibitor of translation at 37° than at 30°. The inhibition of peptide-chain initiation and 40S-initiation complex formation in reticulocyte lysates under other conditions is associated with increased phosphorylation of the α-subunit of protein synthesis initiation factor-2 (eIF-2α) and the inhibition of recycling of this factor. Recycling of eIF-2 is mediated by another protein factor GEF (= guanine nucleotide-exchange factor). The addition of ethanol to reticulocyte lysates led to increased phosphorylation of eIF-2α and to a decrease in the rate of exchange of guanine nucleotides bound to eIF-2. This second finding indicated that recycling of eIF-2 was impaired probably due to decreased availability of GEF. Using purified components it was found that ethanol inhibited the ability of GEF to stimulate eIF-2 and that this inhibition showed a similar temperature dependence to the effect of ethanol on overall protein synthesis. Taken together, these results suggest that ethanol leads to inhibition of peptide-chain initiation both through increased phosphorylation of eIF-2α and by directly inhibiting the productive interaction of eIF-2 and GEF.
UR - http://www.scopus.com/inward/record.url?scp=0023931919&partnerID=8YFLogxK
U2 - 10.1016/0006-2952(88)90555-2
DO - 10.1016/0006-2952(88)90555-2
M3 - Article
C2 - 3377809
AN - SCOPUS:0023931919
SN - 0006-2952
VL - 37
SP - 2045
EP - 2049
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
IS - 10
ER -