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Covalent modification of nuclear proteins during aging.
Federation Proceedings
|February 1, 1975
Summary
Aging increases nuclear protein acetylation in mice, particularly histone F3 and acidic proteins. Phosphorylation of acidic proteins also rises with age, indicating altered nuclear protein modification in older animals.
Area of Science:
- Biochemistry
- Gerontology
- Molecular Biology
Background:
- Nuclear proteins undergo post-translational modifications like acetylation and phosphorylation.
- These modifications play crucial roles in gene regulation and cellular processes.
- Age-related changes in protein modification can impact cellular function and organismal aging.
Purpose of the Study:
- To investigate age-dependent alterations in the acetylation and phosphorylation of nuclear proteins.
- To compare these modifications in young and old mice using an in vitro assay system.
- To identify specific nuclear protein fractions affected by aging.
Main Methods:
- Establishment of an in vitro assay system for studying nuclear protein acetylation and phosphorylation.
- Isolation of nuclei from liver tissues of young (2 mo) and old (29 mo) mice.
- Fractionation of nuclear proteins using polyacrylamide-urea electrophoresis and SDS-polyacrylamide gel electrophoresis.
- Quantification of protein acetylation and phosphorylation levels through radioactive labeling.
Main Results:
- Acetylation of nuclear proteins peaked approximately 15 minutes after phosphorylation.
- Significantly higher rates of liver nuclear protein acetylation were observed in old mice compared to young mice.
- Specific increases in acetylation were noted for histone F3 (129%) and F2al (112%) in old mice.
- Acetylation (250%) and phosphorylation (138%) of phenol-soluble nuclear acidic proteins were elevated in old mice.
- No significant age-related differences were found in the phosphorylation of nuclear proteins or the labeling of nucleoplasmic proteins.
Conclusions:
- Aging is associated with increased acetylation of specific nuclear proteins, including histones and acidic proteins.
- Aging also leads to enhanced phosphorylation of certain nuclear acidic proteins.
- These findings suggest that covalent modification of nuclear proteins is altered during the aging process.
- The observed changes may contribute to age-related functional declines in cellular processes.