scholarly journals Evidence for an ethanolamine cycle: differential recycling of the ethanolamine moiety of phosphatidylethanolamine derived from phosphatidylserine and ethanolamine

1995 ◽  
Vol 310 (2) ◽  
pp. 673-679 ◽  
Author(s):  
Y J Shiao ◽  
J E Vance
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Specific Radioactivity ◽  
Chinese Hamster ◽  
Ovary Cells ◽  
Time Period ◽  
In Cells

Evidence is presented for the operation of an ethanolamine-phosphatidylethanolamine (PtdEtn) cycle in Chinese hamster ovary cells. PtdEtn was labelled with [3H]ethanolamine and radioactivity was chased by incubation with 1 mM unlabelled ethanolamine. Radioactivity in [3H]PtdEtn gradually declined over a 23 h time period. In contrast, when the cells were incubated in medium lacking unlabelled ethanolamine, radioactivity in PtdEtn remained constant for at least 23 h. These observations suggest that the ethanolamine moiety is continuously released from PtdEtn and recycled back into PtdEtn. In cells incubated without unlabelled ethanolamine, labelled ethanolamine released from PtdEtn is re-incorporated into PtdEtn without significant dilution. In contrast, in cells incubated with unlabelled ethanolamine the specific radioactivity of the intracellular ethanolamine pool decreases as a result of dilution by the exogenous ethanolamine, hence radioactivity in PtdEtn gradually declines. Similar results were obtained for confluent and non-confluent cells. Our data also demonstrate that when PtdEtn is derived from phosphatidylserine decarboxylation, the ethanolamine cycle operates only in actively dividing, and not in confluent, cells, implying that PtdEtn derived from different biosynthetic origins [i.e. from decarboxylation of phosphatidylserine or from ethanolamine (most likely via the CDP-ethanolamine pathway)] is metabolized differently.

scholarly journals The role of sphingomyelin in phosphatidylcholine metabolism in cultured human fibroblasts from control and sphingomyelin lipidosis patients and in Chinese hamster ovary cells

1990 ◽  
Vol 268 (3) ◽  
pp. 719-724 ◽  
Author(s):  
M W Spence ◽  
H W Cook ◽  
D M Byers ◽  
F B S C Palmer
Keyword(s):  
Chinese Hamster Ovary ◽  
Cultured Cells ◽  
Chinese Hamster Ovary Cells ◽  
Human Fibroblasts ◽  
Specific Radioactivity ◽  
Chinese Hamster ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Intact Cells ◽  
Ovary Cells

Human fibroblasts in culture take up exogenous [choline-Me-3H,32P]sphingomyelin (SM) from the medium and incorporate it into cellular SM and phosphatidylcholine [Spence, Clarke & Cook (1983) J. Biol. Chem. 258, 8595-8600]. The ratio of [3H]choline/[32P]Pi is similar in SM and phosphatidylcholine, indicating that the phosphocholine (P-Cho) moiety is transferred intact. Similar results are obtained with Niemann-Pick (NP) cells which are deficient in lysosomal sphingomyelinase activity, suggesting that the P-Cho transfer may not be mediated by the lysosomal sphingomyelinase and that alternative pathways of sphingomyelin catabolism are present in cultured cells. In this study we have shown that: (1) the P-Cho pool in control and NP cells incubated with exogenous labelled SM has a specific radioactivity intermediate between that of SM and PtdCho; (2) expansion of the intracellular P-Cho pool by incubation with exogenous choline reduces the incorporation of [3H]choline from SM into PtdCho; and (3) incorporation of P-Cho from SM into PtdCho is decreased at the non-permissive temperature in Chinese hamster ovary cells with a temperature-sensitive mutation in the cytidylyltransferase reaction. These results suggest that incorporation of P-Cho from SM into PtdCho involves a reaction sequence in which P-Cho is hydrolysed from SM by a sphingomyelinase, followed by incorporation of P-Cho into PtdCho via the cytidine pathway of biosynthesis (SM----P-Cho----CDP-Cho----PtdCho). The appreciable incorporation of P-Cho from SM into PtdCho in sphingomyelinase-deficient NP cells suggests a more substantial or effective lysosomal sphingomyelinase activity in intact cells than is measured in vitro, and/or a significant contribution by other sphingomyelinase activities in these cells.

scholarly journals Control of the Cardiac Muscarinic K+Channel by β-Arrestin 2

2001 ◽  
Vol 276 (15) ◽  
pp. 11691-11697 ◽  
Author(s):  
Z. Shui ◽  
I. A. Khan ◽  
T. Haga ◽  
J. L. Benovic ◽  
M. R. Boyett
Keyword(s):  
Muscarinic Receptor ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
K Channel ◽  
Receptor Kinase ◽  
Ovary Cells ◽  
M2 Muscarinic Receptor ◽  
Receptor Channel ◽  
In Cells

Control of the cardiac muscarinic K+current (iK,ACh) by β-arrestin 2 has been studied. In Chinese hamster ovary cells transfected with m2 muscarinic receptor, muscarinic K+channel, receptor kinase (GRK2), and β-arrestin 2, desensitization of iK,AChduring a 3-min application of 10 μmACh was significantly increased as compared with that in cells transfected with receptor, channel, and GRK2 only (fade in current increased from 45 to 78%). The effect of β-arrestin 2 was lost if cells were not co-transfected with GRK2. Resensitization (recovery from desensitization) of iK,AChin cells transfected with β-arrestin 2 was significantly slowed (time constant increased from 34 to 232 s). Activation and deactivation of iK,AChon application and wash-off of ACh in cells transfected with β-arrestin 2 were significantly slowed from 0.9 to 3.1 s (time to half peak iK,ACh) and from 6.2 to 13.8 s (time to half-deactivation), respectively. In cells transfected with a constitutively active β-arrestin 2 mutant, desensitization occurred in the absence of agonist (peak current significantly decreased from 0.4 ± 0.05 to 0.1 ± 0.01 nA). We conclude that β-arrestin 2 has the potential to play a major role in desensitization and other aspects of the functioning of the muscarinic K+channel.

Malignancy-related characteristics of wild type and drug-resistant chinese hamster ovary cells

Pathology ◽  
1993 ◽  
Vol 25 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Wanda B. Mackinnon ◽  
Marlen Dyne ◽  
Rebecca Hancock ◽  
Carolyn E. Mountford ◽  
Adrienne J. Grant ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Drug Resistant ◽  
Wild Type ◽  
Ovary Cells

Review of the current methods of Chinese Hamster Ovary (CHO) cells cultivation for production of therapeutic protein

2020 ◽  
Vol 17 ◽  
Author(s):  
Shazid Md. Sharker ◽  
Md. Atiqur Rahman
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Mass Production ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Therapeutic Protein ◽  
Specific Productivity ◽  
Ovary Cells ◽  
Further Development ◽  
Interesting Area

Most of clinical approved protein-based drugs or under in clinical trial have a profound impact in the treatment of critical diseases. The mammalian eukaryotic cells culture approaches, particularly the CHO (Chinese Hamster Ovary) cells are mainly used in the biopharmaceutical industry for the mass-production of therapeutic protein. Recent advances in CHO cell bioprocessing to yield recombinant proteins and monoclonal antibodies have enabled the expression of quality protein. The developments of cell lines are possible to upgrade specific productivity. As a result, it holds an interesting area for academic as well as industrial researchers around the world. This review will concentrate on the recent progress of the mammalian CHO cells culture technology and the future scope of further development for the mass-production of protein therapeutics.

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