Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. III. Genetic evidence for utilization of phosphatidylcholine and phosphatidylethanolamine as precursors
We reported that Chinese hamster ovary (CHO) cells contain two different serine-exchange enzymes (I and II) which catalyze the base-exchange reaction of phospholipid(s) with serine and that a phosphatidylserine-requiring mutant (strain PSA-3) of CHO cells is defective in serine-exchange enzyme I and lacks the ability to synthesize phosphatidylserine. In this study, we examined precursor phospholipids for phosphatidylserine biosynthesis in CHO cells. When mutant PSA-3 and parent (CHO-K1) cells were cultured with (/sup 32/P)phosphatidylcholine, phosphatidylserine in the parent accumulated radioactivity while that in the mutant was not labeled significantly. On the contrary, when cultured with (/sup 32/P)phosphatidylethanolamine, the mutant incorporated the label into phosphatidylserine more efficiently than the parent. Furthermore, we found that mutant PSA-3 grew normally in growth medium supplemented with 30 microM phosphatidylethanolamine as well as phosphatidylserine and that the biosynthesis of phosphatidylserine in the mutant was normal when cells were cultured in the presence of exogenous phosphatidylethanolamine. The simplest interpretation of these findings is that phosphatidylserine in CHO cells is biosynthesized through the following sequential reactions: phosphatidylcholine----phosphatidylserine----phosphatidylethanolamine--- - phosphatidylserine. The three reactions are catalyzed by serine-exchange enzyme I, phosphatidylserine decarboxylase, and serine-exchange enzyme II, respectively.
- Research Organization:
- National Institute of Health, Tokyo, Japan
- OSTI ID:
- 5491632
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 13
- Country of Publication:
- United States
- Language:
- English
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Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. I. Inhibition of de novo phosphatidylserine biosynthesis by exogenous phosphatidylserine and its efficient incorporation
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Related Subjects
CHO CELLS
GROWTH
SERINE
BIOSYNTHESIS
CELL CULTURES
CELL DIVISION
CHOLINE
DECARBOXYLASES
HAMSTERS
MUTANTS
PHOSPHATES
PHOSPHOLIPIDS
PHOSPHORUS 32
PRECURSOR
TRACER TECHNIQUES
ALCOHOLS
AMINES
AMINO ACIDS
AMMONIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON-CARBON LYASES
CARBOXY-LYASES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DRUGS
ENZYMES
ESTERS
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LIPOTROPIC FACTORS
LYASES
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
QUATERNARY COMPOUNDS
RADIOISOTOPES
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques