Protein Turnover

Lajtha, Ábel; Marks, Neville

doi:10.1007/978-1-4615-7169-8_6

Cited by 7 publications

(5 citation statements)

References 282 publications

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“…5 and Table I). Various values have been reported for the average half‐lives for membrane proteins: 20–24 days in mitochondrial fractions containing synaptosomes (Lajtha and Marks, 1971) and 7 days in synaptosomes (Dunlop, 1983), both of which were calculated from the incorporation rate, and 5.8 days in synaptic membranes as calculated from the decay curve (Chee and Dahl, 1978). The half‐lives of synaptophysin obtained in the present study lie in the range of those reported values.…”

Section: Discussionmentioning

confidence: 99%

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Ando¹,

Tanaka²,

Toyoda³

et al. 2002

J of Neuroscience Research

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We examined age-related changes in the turnover rates of synaptic membrane components that might underlie the decrease in synaptic functions in senescence. Synaptic membrane constituents were labeled in vivo with deuterium and the disappearance of the deuterated molecules from synaptic membranes was measured by mass spectrometry. The turnover rates of phosphatidylcholine, phosphatidylethanolamine, cholesterol, and synaptophysin were all shown to slow down with aging. Dietary restriction, which is known to retard various aging processes, was found to decrease the turnover rates of membrane lipid species. Consequently, the fatty acid composition in phospholipids remained unchanged in the synaptic plasma membranes of food restricted mice. In contrast, the turnover rate of synaptophysin was accelerated under dietary restriction. This may mean that increased turnover enhances the removal of damaged proteins from membranes.

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Section: Discussionmentioning

confidence: 99%

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Ando¹,

Tanaka²,

Toyoda³

et al. 2002

J of Neuroscience Research

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“…The rate of incorporation of leucine into Aplysia neuronal protein allows a very approximate general half-life of more than 100 days to be calculated. When compared with reported half-lives of proteins in mammals (1-2 wk; Lajtha and Marks, 1971) the very different temperatures of the organisms must be kept in mind. A Q~0 of about 3 would account for the difference.…”

Section: Discussionmentioning

confidence: 99%

Patterns of proteins synthesized in the R15 neuron of Aplysia. Temporal studies and evidence for processing.

Strumwasser

Wilson²

1976

The Journal of General Physiology

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A B S T RA C T The time-course of changes in the pattern of newly synthesized proteins in the RI5 neuron of the parietovisceral ganglion ofAplysia californica has been studied at 14°C. 5% polyacrylamide gels containing sodium dodecyl sulfate (SDS) have been used to separate newly synthesized (leucine-labeled) proteins from the neuron. We have demonstrated that the pattern of newly synthesized proteins from the R15 neuron does not change significantly if 5-h pulses of labeled leucine are given during the first 72 h of in vitro incubation of the excised ganglion. However, the level of leucine incorporation begins to decline somewhere between 17 and 43 h after the ganglion is isolated; at 43 and 69 h the levels of incorporation fell to 29 and 10% of the initial level, respectively.A number of condusions have been drawn from the use of a sequential, doublelabel type of experiment in the same cell. There is processing of SDS-soluble, 12,000-dalton (12k) material to 6,000-9,000-dalton (6-9k) material. These materials are the two major peaks on gels after long labeling periods and together account for about 35% of all newly synthesized proteins. After synthesis of 12k material, there is a gradual disappearance of 12k (half-life about 8 h) and simultaneous appearance of 6-9k material on the gels, as the postsynthesis "chase" period of ganglia incubation is increased. The processing of 12k to 6--9k material occurs even in the presence of anisomycin, a protein synthesis inhibitor, during the chase period. While the rate of 12k to 6-9k conversion can vary from cell to cell, it appears to remain consistent within, and is characteristic of, any individual RI5. We detect no circadian rhythm in either the rate of 12k synthesis or the rate of 12k to 6-9k processing with 5-h label periods. These results are discussed in relation to the roles of 12k and 6-9k material in the R15 neuron.

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“…THE DYNAMICS of protein turnover provide important insights into CNS function at the cellular level (LAJTHA & MARKS, 1971). Continuous renewal of proteins in all cell types and functional and anatomical regions of brain provides mechanisms by which the organism can respond and adapt to various stimuli.…”

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confidence: 99%

MEASUREMENT OF PROTEIN TURNOVER IN RAT BRAIN¹

Chee

Dahl

1978

Journal of Neurochemistry

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Abstract— Degredation rates of rat brain proteins were measured by following the decay in specific radioactivity of carboxyl labelled aspartate and glutamate over a 17‐day period. Initial labelling of these amino acids was achieved by a single intraperitoneal injection 0f NaH14CO3. The non‐linear decay curve for total brain proteins could be approximated by assuming that the mixture contained two classes of proteins with half‐lives of 3.3 and 8.7 days, respectively. Half‐lives of 2.5 and 7.7 days were estimated for such protein classes in the microsomal fraction. The half‐lives of soluble proteins, synaptic membranes, cell body and synaptic mitochondria were 3.1, 5.8, 5.6 and 8.4 days, respectively. Identical results were obtained if the change in specific activity of intact protein labeled by NaH14CO3 was followed. Two‐fold slower decay rates were obtained when brain proteins were labeled with a pulse of [4,5‐3H]leucine or [l‐14C]leucine. Half‐lives calculated for the two classes of proteins in whole brain were 8.4 and 16.5 days, respectively with [4,5‐3H]leucine and 8.9 and 14.2 days, respectively with [1‐14C]leucine. These results indicate the very significant reutilization of this amino acid in brain. Sodium [14C]bicarbonate is a more satisfactory isotopic precursor for accurate assessment of rates of protein turnover in brain.

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Protein Turnover

Cited by 7 publications

References 282 publications

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Patterns of proteins synthesized in the R15 neuron of Aplysia. Temporal studies and evidence for processing.

MEASUREMENT OF PROTEIN TURNOVER IN RAT BRAIN¹

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Protein Turnover

Cited by 7 publications

References 282 publications

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Turnover of synaptic membranes: Age‐related changes and modulation by dietary restriction

Patterns of proteins synthesized in the R15 neuron of Aplysia. Temporal studies and evidence for processing.

MEASUREMENT OF PROTEIN TURNOVER IN RAT BRAIN1

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MEASUREMENT OF PROTEIN TURNOVER IN RAT BRAIN¹