Control of eIF-2 phosphatase activity in rabbit reticulocyte lysate.
- 1 March 1979
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 76 (3) , 1094-1098
- https://doi.org/10.1073/pnas.76.3.1094
Abstract
A sensitive assay requiring pmol amounts of [32P]eIF-2 to measure eIF-2 phosphatase activity was developed. Dephosphorylation of [32P]eIF-2.alpha. (38,000 dalton subunit) is extremely rapid (t1/2 = 20 s) and occurs at the same rate in both hemin-supplemented and hemin-depleted lysates. In contrast, [32]eIF-2.beta. phosphate is stable under all conditions studied. At concentrations required to produce a transient inhibition of protein synthesis, GDP prevents dephosphorylation of half of the phosphate introduced on eIF-2.alpha. by the hemin-controlled repressor. Equimolar GTP is without effect. The concept that the energy charge of the guanylate pool may regulate accessibility of a phosphorylated site on eIF-2.alpha. to its phosphatase and the implication of this to the mechanism of hemin-regulated translational control are discussed.This publication has 29 references indexed in Scilit:
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