Ornithine decarboxylase inactivation in HeLa cells

Prouty, W F

doi:10.1002/jcp.1040890107

Cited by 46 publications

(20 citation statements)

References 31 publications

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“…2), we conclude that ATP must function at an initial stage of ODC degradation. Our findings are in agreement with an earlier study demonstrating an ATP requirement for the decay of ODC activity [45]. However, they contradict two recent studies which concluded that ODC degradation is an ATP-independent process [46, 471. It is unclear how we can reconcile our conclusions and those of one of the other studies [46], as in each case a similar experimental approach was utilized.…”

Section: Discussionsupporting

confidence: 90%

Degradation of ornithine decarboxylase in mammalian cells is ATP dependent but ubiquitin independent

Rosenberg-Hasson

Bercovich

Ciechanover

et al. 1989

European Journal of Biochemistry

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Ornithine decarboxylase (ODC), a key enzyme in the biosynthesis of polyamines in mammalian cells is characterized by an extremely short half-life. In the present study, ODC degradation was investigated in 653-1 mouse myeloma cells that overproduce ODC and in ts85 cells that are thermosensitive for conjugation of ubiquitin to target proteins. Addition of 2-deoxyglucose and dinitrophenol (agents that efficiently deplete cellular ATP) to the growth medium of these cells inhibited ODC degradation. In contrast, chloroquine and leupeptin, inhibitors of intralysosomal proteolysis, did not affect ODC degradation. Shifting ts85 cells to 42 "C (a non-permissive temperature that inhibited conjugation of ubiquitin to target proteins) did not prevent ODC degradation. The ATP-dependent degradation of ODC in 653-1 cells was inhibited substantially by N"-tosyl-L-lysine chloromethane (TosPheMeCl), iodoacetamide and o-phenanthroline. These results suggest that ODC degradation occurs via a non-lysosomal, ATP-requiring and ubiquitin-independent cellular proteolytic mechanism, and that serine proteases and enzymes containing sulphydryl groups and metalloenzyme(s) may be involved in this process.Ornithine decarboxylase is a key enzyme in the biosynthetic pathway of polyamines in mammalian cells 111. This pyridoxal-phosphate-dependent enzyme that decarboxylates ornithine to form putrescine is characterized by a high turnover rate [2] and by a rapid and dramatic induction in response to stimulation by a variety of growth stimuli [3,4]. Accumulating evidence suggests that ODC expression is regulated at several levels: production of mRNA [5-91, changes in the efficiency of mRNA translation [lo ~ 121, changes in protein stability [I 31 and by posttranslational modifications and interactions [lo, 11, 14-161. The extremely short half-life of ODC permits rapid adjustment of its activity by these regulatory mechanisms.The mechanisms involved in intracellular protein degradation are still poorly understood. Nevertheless, it is widely accepted that lysosomes are involved in degradation of endocytosed proteins and of cellular proteins under conditions of nutritional deprivation [17 -191. In contrast, nonlysosomal ATP-requiring pathways are engaged in selective degradation of short-lived proteins under normal metabolic conditions [17 -191. While the multiplicity of distinct nonlysosomal proteolytic mechanisms in mammalian cells is still unknown, a non-lysosomal ATP-dependent proteolytic system has been characterized and partially purified from rabbit reticulocytes [20,21]. This proteolytic system contains several essential components; among them the ubiquitin polypeptide whose ATP-dependent conjugation to target proteins represents an initial obligatory step in their degradation. The mouse cell-cycle mutant cell-line, ts85 122, 231, fails to conjugate ubiquitin at the non-permissive temperature [24], due to thermolability of its ubiquitin-activating enzyme E l [25]. One of these studies [24] has actually suggested that the degradation of the bul...

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Section: Discussionsupporting

confidence: 90%

Degradation of ornithine decarboxylase in mammalian cells is ATP dependent but ubiquitin independent

Rosenberg-Hasson

Bercovich

Ciechanover

et al. 1989

European Journal of Biochemistry

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“…Furthermore, the turnover rate of ODC is itself subject to marked changes depending on cellular conditions, indicating that its degradation is also regulated. Thus, with various ODC-inducing stimuli, ODC in cultured cells is in general stabilized during the ascending phase of its induction and destabilized during the descending phase [35,36]. These changes in the turnover rate should act, by stimulating both its ascending and descending rates, not only to amplify its induction, but also to make its pattern more pulselike.…”

Section: Historical Background Rapid Turnover Of Odcmentioning

confidence: 99%

Rapid and regulated degradation of ornithine decarboxylase

Hayashi

Murakami

1995

Biochemical Journal

194

131

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“…ADC' has been implicated in the regulation of polyamine biosynthesis in other plant and bacterial systems (4,(11)(12)(13)(14)(15). Its mammalian counterpart, ornithine decarboxylase, varies in response to many kinds of developmental events and environmental stimuli (7,9,10,16,17 mCi/mmol) and 0.01 ml of 5 mm pyridoxal-5'-phosphate. In some cases, these volumes were halved.…”

Section: Introductionmentioning

confidence: 99%

Polyamine Metabolism in Embryogenic Cells of Daucus carota

Montague¹,

Armstrong²,

Jaworski³

1979

Plant Physiol.

118

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Embryogenic cultured cells of Daucus caota have been shown to synthesize putrescine from exogenously supplied 114Cjarginine at twice the rate of control nonembryogenic cells. In the present paper, the activity of argni decarboxylase (arginine carboxy-lyase, EC 4.1.1.19), an important enzyme in the synthesis of putrescine, was assayed and also found to be elevated by as much as 2-fold in embryogenic cells. This difference between embryogenic and nonembryogenic cells was observed as early as 6 hours after the induction of embryogenesis and appeared not to result from the presence of a diffusible inhibitor or activator. It seemed to be dependent upon concomitant RNA and protein synthesis, as judged using 6-methylpurine and cycloheximide. After cycloheximide addition to the culture medium, arginine decarboxylase activity declined with a half-time of about 30 minutes in both embryogenic and nonembryogenic cells. It is suggested that elevated arginine decarboxylase activity is involved in the mechanism leading to elevated putrescine levels in these cells and hence may play a role in the embryogenic process.In a previous paper (8), results were presented which showed substantial differences between embryogenic and nonembryogenic carrot cells with regard to their metabolism of polyamines. The levels of putrescine and spermidine rose in embryogenic cells compared with the control, whereas the level of spermine fell. Also, the rate of synthesis of putrescine appeared to be about 2-fold higher in embryogenic cells, as judged by the incorporation of radioactivity after a pulse of ["4Clarginine. These differences occurred within 24 hr after transfer of the cells to embryogenic medium.Because polyamines may therefore be involved in the process of carrot embryogenesis, it seemed important to examine the basis for this alteration in polyamine metabolism. To this end, the activity of arginine decarboxylase (arginine carboxy-lyase EC 4.1.1.19) was determined. ADC' has been implicated in the regulation of polyamine biosynthesis in other plant and bacterial systems (4,(11)(12)(13)(14)(15). Its mammalian counterpart, ornithine decarboxylase, varies in response to many kinds of developmental events and environmental stimuli (7,9,10,16,17 mCi/mmol) and 0.01 ml of 5 mm pyridoxal-5'-phosphate. In some cases, these volumes were halved. The test tubes containing all components of the assay were capped with special rubber stoppers fitted with plastic center wells (Kontes Glass Co., K-882310 and K-882320) containing 0.1 ml of 2 N KOH on a Whatman No. 1 paper wick. The reaction was allowed to proceed for 60 min at 30 C in a shaking water bath (100 oscillations/min) and was terminated by the injection of 0.5 ml of 1 N H2SO4 into the reaction solution. After an additional 60 min of shaking, the center wells were removed, and the paper wicks were placed in scintillation vials with 3 ml of H20 and 10 ml of Packard Insta-gel scintillation fluid. Counting efficiency was about 80%1o. Blank values were obtained either by using boiled crude e...

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Ornithine decarboxylase inactivation in HeLa cells

Cited by 46 publications

References 31 publications

Degradation of ornithine decarboxylase in mammalian cells is ATP dependent but ubiquitin independent

Degradation of ornithine decarboxylase in mammalian cells is ATP dependent but ubiquitin independent

Rapid and regulated degradation of ornithine decarboxylase

Polyamine Metabolism in Embryogenic Cells of Daucus carota

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