Neutral amino acid transport systems in Chinese hamster ovary cells.

Shotwell, Mark A.; Jayme, David W.; Kilberg, Michael S.; Oxender, Dale L.

doi:10.1016/s0021-9258(19)69218-5

Cited by 183 publications

(13 citation statements)

References 30 publications

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“…omitted the glutamine inhibitory fraction (GIF) from consideration since it contributes little to the overall Na+-dependent proline transport and has not been sufficiently characterized. The A system is operationally defined as the increment of velocity of amino acid transport that is inhibited by saturating amounts of MeAIB (Bass et al, 1981;Shotwell et al, 1981;Moffett et al, 1983). To determine the extent of transport of proline through the A system in vesicles, we had to determine whether MeAIB inhibited proline transport and the amount of MeAIB that would be required to completely exclude the A system.…”

Section: Resultsmentioning

confidence: 99%

Amino acid transport in membrane vesicles from CHO-K1 and alanine-resistant transport mutants

Moffett¹,

Jones²,

Englesberg³

1987

Biochemistry

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Membrane vesicles were prepared from CHO-K1 and alanine-resistant transport mutants, alar4 and alar4-H3.9. Alar4 is a constitutive mutant of the A system, and alar4-H3.9, derived from alar4, may be the result of amplification of a gene coding for an A-system transporter. Under conditions in which the same membrane potential (interior negative) and Na+ gradient were employed, the mutant vesicles show increases in the A system over that of the parental CHO-K1 cell line, paralleling, but not equivalent to, that found in whole cells. L-system and 5'-nucleotidase activities of these vesicles were similar, indicating that the increased A-system activity of the mutant vesicles is not due to the differential enrichment of the A system in these vesicles. The membrane potential was produced by a K+ diffusion gradient (internal greater than external) in the presence of valinomycin or by the addition of a Na+ salt of a highly permeant anion such as SCN-. Monensin was employed to study the effect of the Na+ gradient on transport and membrane potential. The latter was determined by measuring the uptake of tetraphenylphosphonium ion. A negative membrane potential determines the concentrative ability and the initial velocity of the A system in these vesicles. The concentration of external Na+ has a stimulatory effect on the initial velocity of this system. However, the Na+ gradient (external greater than internal) has no effect on the initial velocity or the membrane potential when the potential is set by valinomycin and high internal K+. Little if any ASC system could be detected in vesicles from CHO-K1.

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Section: Resultsmentioning

confidence: 99%

Amino acid transport in membrane vesicles from CHO-K1 and alanine-resistant transport mutants

Moffett¹,

Jones²,

Englesberg³

1987

Biochemistry

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“…This is further supported by competition experiments using several natural amino acids and analogs (Table II) which exhibited varying degrees of competitive inhibition. Such experiments may also be interpreted in terms of the systems of amino acid transport described in studies by numerous investigators on a variety of cells (Christensen, 1979;Kilberg etaL 1980Kilberg etaL , 1981Handlogten et ai, 1981;Shotwell et al, 1981;Christensen, 1982). System ASC appears to be the primary transport mechanism for alanine since MeAIB, an inhibitor of System A but not ASC, was ineffective in suppressing uptake.…”

Section: Discussionmentioning

confidence: 90%

“…It should be noted that the ratio of these uptake systems varies widely among the many types of cells studied and may not remain constant within a given cell type. Adaptive changes in the activity of System A in animal cells have been demonstrated with respect to varying exogenous levels of relevant amino acids (Gazzola et al, 1981;Shotwell et al, 1981). Cells incubated under conditions of amino acid deprivation demonstrated increased System A activity, while those exposed to high levels of exogenous amino acids showed depressed uptake.…”

Section: Discussionmentioning

confidence: 99%

ALANINE UPTAKE BY ISOLATED ZOOXANTHELLAE OF THE MANGROVE JELLYFISH,CASSIOPEA XAMACHANA.I. TRANSPORT MECHANISMS AND UTILIZATION

Carroll¹,

Blanquet²

1984

The Biological Bulletin

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Freshly isolated zooxanthellae of the mangrove jellyfish Cassiopea xamachana were found to take up exogenous l4 C-alanine and incorporate the radiolabel into various cellular components. Transport was highly Na + -dependent and lacked stereospecificity. Competition experiments with several L-amino acids and alanine analogs exhibited varying degrees of competitive inhibition, and these results are discussed in relation to the well described neutral amino acid transport systems known for many eukaryotic cells. Inhibition of uptake by KCN and N-ethylmaleimide indicated an active process and a significant electrogenic component to the energetics of uptake. Uptake of alanine was not affected by the inhibition of photosynthesis.

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“…To check the presence of the L-type amino acid transporter LAT1, we performed a short in vitro evaluation of [ 125 I]-2-iodo-L-phenylalanine uptake in all cell lines used. The method we used has been described by Shotwell et al and is frequently used to determine the relative contribution of the individual neutral transporter systems involved [11]. Using R1M cells and 4F2hc-LAT1 transfected oocytes, respectively, Mertens et al and Yanagida et al described in earlier work that [ 125 I]-2-iodo-D-phenylalanine is taken up by the same transporter system with the same affinity for LAT1 as compared with its L-isomer [7,12].…”

Section: In Vitro Experimentsmentioning

confidence: 99%

123/125I-labelled 2-iodo-L-phenylalanine and 2-iodo-D-phenylalanine: comparative uptake in various tumour types and biodistribution in mice

Kersemans

Cornelissen

Kersemans

et al. 2006

Eur J Nucl Med Mol Imaging

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Neutral amino acid transport systems in Chinese hamster ovary cells.

Cited by 183 publications

References 30 publications

Amino acid transport in membrane vesicles from CHO-K1 and alanine-resistant transport mutants

Amino acid transport in membrane vesicles from CHO-K1 and alanine-resistant transport mutants

ALANINE UPTAKE BY ISOLATED ZOOXANTHELLAE OF THE MANGROVE JELLYFISH,CASSIOPEA XAMACHANA.I. TRANSPORT MECHANISMS AND UTILIZATION

123/125I-labelled 2-iodo-L-phenylalanine and 2-iodo-D-phenylalanine: comparative uptake in various tumour types and biodistribution in mice

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