Regulation of protein synthesis in rabbit reticulocyte lysates by guanosine triphosphate |
| |
Authors: | Rajinder Singh Ranu |
| |
Institution: | 1. Department of Microbiology Colorado State University Fort Collins, Colorado 80523 USA;2. the Graduate Program in Cellular and Molecular Biology Colorado State University Fort Collins, Colorado 80523 USA |
| |
Abstract: | GTP (2 mM) promotes protein synthesis in rabbit reticulocyte lysates in which protein chain initiation is inhibited by the activation of specific adenosine 3′:5′ cyclic monophosphate independent protein kinases in: 1) heme deficiency; or 2) in hemin-supplemented lysates by the addition of the purified heme-regulated protein kinase (HRI); or 3) oxidized glutathione; or 4) by low levels of double stranded RNA. The molecular basis for the promotion of protein synthesis by GTP under these various conditions was investigated by examining the state of eIF-2 phosphorylation. The results show that GTP (2 mM) blocks eIF-2 phosphorylation and also promotes the dephosphorylation of phosphorylated eIF-2. These findings suggest that GTP restores protein synthesis by a common mechanism that involves the relief of eIF-2 from phosphorylation. The nonphosphorylated eIF-2 is, therefore, available for the maintenance and the restoration of protin chain initiation cycle. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|