Age-dependent Decrease in the Amount of Eukaryotic Initiation Factor 2 in Various Rat Tissues
Overview
Authors
Affiliations
Recent studies have suggested that the decline in protein synthesis that occurs in rat liver and brain during development and aging is associated with a decrease in the activity of eukaryotic initiation factor 2 (eIF-2). One way in which eIF-2 activity could be decreased in tissue extracts would be through a decrease in the activity of the GDP exchange factor, eIF-2B. In the present study, the activity of eIF-2B was measured in tissue extracts and was found to be less in older than in younger rats. Thus a decrease in eIF-2B activity could account for part of the decrease in protein synthesis that occurs during aging. Another way in which eIF-2 activity could be decreased would be through a decrease in amount of the protein. Therefore the amount of eIF-2 in various tissues was quantified by protein immunoblot analysis. We found that the amount of eIF-2 relative to total protein tended to fall with increasing age. Furthermore, eIF-2 content was directly proportional to the rate of protein synthesis in the tissues examined. Finally, slot-blot analysis of polyadenylated RNA revealed no significant change in the relative abundance of eIF-2 alpha mRNA with age. The last-mentioned experiments suggest that the synthesis of eIF-2 may be regulated through changes in the deficiency of translation of eIF-2 alpha mRNA rather than through changes in gene transcription.
Regulating translation in aging: from global to gene-specific mechanisms.
Solyga M, Majumdar A, Besse F EMBO Rep. 2024; 25(12):5265-5276.
PMID: 39562712 PMC: 11624266. DOI: 10.1038/s44319-024-00315-2.
G-quadruplexes and associated proteins in aging and Alzheimer's disease.
Vijay Kumar M, Morales R, Tsvetkov A Front Aging. 2023; 4:1164057.
PMID: 37323535 PMC: 10267416. DOI: 10.3389/fragi.2023.1164057.
Protein translation paradox: Implications in translational regulation of aging.
Kim H, Pickering A Front Cell Dev Biol. 2023; 11:1129281.
PMID: 36711035 PMC: 9880214. DOI: 10.3389/fcell.2023.1129281.
Age modulates liver responses to asparaginase-induced amino acid stress in mice.
Nikonorova I, Zhu Q, Signore C, Mirek E, Jonsson W, Kong B J Biol Chem. 2019; 294(38):13864-13875.
PMID: 31413113 PMC: 6755797. DOI: 10.1074/jbc.RA119.009864.
Mobley C, Mumford P, Kephart W, Haun C, Holland A, Beck D Front Physiol. 2017; 8:518.
PMID: 28775694 PMC: 5517446. DOI: 10.3389/fphys.2017.00518.