Na+-independent transport of basic and zwitterionic amino acids in mouse blastocysts by a shared system and by processes which distinguish between these substrates.

Winkle, Lon J. Van; Campione, Allan L.; Gorman, James M.

doi:10.1016/s0021-9258(18)69048-9

Cited by 168 publications

(14 citation statements)

References 40 publications

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“…It has to be pointed out that the mammalian system b! ,+ , as characterized in mouse blastocysts, cannot be inhibited by BCH [26]. It is widely accepted that BCH is a specific inhibitor of system L. Including the transport activity described in the present work, three transport systems are now known that are sensitive to inhibition by BCH, namely system L [27], system B!…”

Section: Figure 7 Comparison Of the Characteristics Of R4f2hc And H4f2hcmentioning

confidence: 65%

Discrimination of two amino acid transport activities in 4F2 heavy chain- expressing Xenopus laevis oocytes

Hamprecht

Bröer

1998

Biochemical Journal

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Expression of the type II membrane proteins of the rbAT/4F2hc family in Xenopus laevisoocytes results in the induction of amino acid transport activity. To elucidate the mechanism of action, amino acid transport was investigated in oocytes expressing the surface antigen 4F2hc. Leucine transport was mediated by a Na+-independent and a Na+-dependent transport mechanism. Both systems could be further discriminated by their stereochemical constraints. Isoleucine, with a branch at the β-position, shared only the Na+-independent transport system with leucine. Both transport systems were sensitive to inhibition by arginine, but only the Na+-independent system was sensitive to inhibition by 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid. When compared with known transport systems the two transport activities could be described as similar to, but not identical with, mammalian systems b0,+ and y+L. The Na+-independent b0,+-like transport system was found both in rbAT and 4F2hc expressing oocytes, indicating that both proteins act in a similar way.

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Section: Figure 7 Comparison Of the Characteristics Of R4f2hc And H4f2hcmentioning

confidence: 65%

Discrimination of two amino acid transport activities in 4F2 heavy chain- expressing Xenopus laevis oocytes

Hamprecht

Bröer

1998

Biochemical Journal

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“…The sodium-independent amino acid transport system includes broad-scope neutral amino acid system L, 31 small neutral amino acid system asc, 32 aromatic amino acid selective T, 33 basic amino selective system y + , 34 basic and neutral amino acid transport systems b 0,+ and y + L, and cystine and glutamate selective system xc . [35][36][37] It has been reported that MDCK cells express various neutral and cationic amino acid transporters on the apical membrane. 38 However, expression of these transporters by the MDCKII-MDR1 cell line has not yet been confirmed.…”

Section: Discussionmentioning

confidence: 99%

Circumventing P-Glycoprotein-Mediated Cellular Efflux of Quinidine by Prodrug Derivatization

et al. 2004

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The objective of this study is to investigate whether transporter-targeted prodrug derivatization of quinidine, a model P-glycoprotein (P-gp) substrate, can circumvent P-gp-mediated efflux. The L-valine ester of quinidine (val-quinidine) was synthesized in our laboratory. Uptake and transport studies were carried out using the MDCKII-MDRI cell line at 37 degrees C for 10 min and 3 h, respectively. [3H]Ritonavir and cyclosporine were also used as model P-gp substrates to delineate the kinetics of translocation of val-quinidine across the MDCKII-MDRI cell monolayer. The rate of uptake of [3H]ritonavir by MDCKII-MDRI cells exhibited a 2-fold increase in the presence of 75 microM quinidine, but 75 microM val-quinidine did not demonstrate any effect on [3H]ritonavir uptake. The rate of transport of quinidine from the basolateral to the apical membrane [(18.3 +/- 1.25) x 10(-6) cm s(-1)] and from the apical to the basolateral membrane [(6.5 +/- 0.66) x 10(-6) cm s(-1)] exhibited a 3-fold difference. However, transport of val-quinidine from the apical to the basolateral membrane [(5.13 +/- 0.49) x 10(-6) cm s(-1)] and from the basolateral to the apical membrane [(6.17 +/- 1.28) x 10(-6) cm s(-1)] did not demonstrate any statistically significant difference. Moreover, cyclosporine, a potent P-gp substrate and/or inhibitor, did not alter the transport kinetics of val-quinidine. The rates of uptake of [3H]Gly-Sar and various amino acid model substrates were reduced in the presence of 200 microM val-quinidine. Results from this study clearly indicate that prodrug derivatization of quinidine into val-quinidine can overcome P-gp-mediated efflux. Val-quinidine once bound to a peptide or amino acid transporter is probably not recognized and cannot be accessed by the P-gp efflux pump. Transporter-targeted prodrug derivatization seems to be a viable strategy for overcoming P-gp-mediated efflux.

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“…Three different CAT genes (SLC7A1, SLC7A2, and SLC7A3) have been cloned, which encode for four homologous proteins cationic amino acid transporter (CAT) (CAT-1, CAT-2A, CAT-2B, and CAT-3), respectively, in animal tissues including the uterus and placenta [120]. In addition, systems b o,+ and B o,+ , which are expressed in mouse blastocysts [121], can transport neutral amino acids as well as cationic amino acids [122]. These two systems are distinguished by their dependence on Na + in that system B o,+ is Na + -dependent, while system b o,+ is Na + -independent.…”

Section: Arginine Catabolismmentioning

confidence: 99%

Mechanisms for the establishment and maintenance of pregnancy: synergies from scientific collaborations†

Bazer

Burghardt

Johnson

et al. 2018

Biology of Reproduction

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Research on the functions of interferon tau (IFNT) led to the theory of pregnancy recognition signaling in ruminant species. But IFNT does much more as it induces expression of interferon regulatory factor 2 (IRF2) in uterine luminal (LE), superficial glandular (sGE), but not glandular (GE) epithelia. First, IRF2 silences transcription of the estrogen receptor alpha gene and, indirectly, transcription of the oxytocin receptor gene to abrogate development of the luteolytic mechanism to prevent regression of the corpus luteum and its production of progesterone for establishing and maintaining pregnancy. Second, IRF2 silences expression of classical interferon-stimulated genes in uterine LE and sGE; however, uterine LE and sGE respond to progesterone (P4) and IFNT to increase expression of genes for transport of nutrients into the uterine lumen such as amino acids and glucose. Other genes expressed by uterine LE and sGE encode for adhesion molecules such as galectin 15, cathepsins, and cystatins for tissue remodeling, and hypoxia-inducible factor relevant to angiogenesis and survival of blastocysts in a hypoxic environment. IFNT is also key to a servomechanism that allows uterine epithelia, particularly GE, to proliferate and to express genes in response to placental lactogen and placental growth hormone in sheep. The roles of secreted phosphoprotein 1 are also discussed regarding its role in implantation in sheep and pigs, as well as its stimulation of expression of mechanistic target of rapamycin mRNA and protein which is central to proliferation, migration, and gene expression in the trophectoderm cells.

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Na+-independent transport of basic and zwitterionic amino acids in mouse blastocysts by a shared system and by processes which distinguish between these substrates.

Cited by 168 publications

References 40 publications

Discrimination of two amino acid transport activities in 4F2 heavy chain- expressing Xenopus laevis oocytes

Discrimination of two amino acid transport activities in 4F2 heavy chain- expressing Xenopus laevis oocytes

Circumventing P-Glycoprotein-Mediated Cellular Efflux of Quinidine by Prodrug Derivatization

Mechanisms for the establishment and maintenance of pregnancy: synergies from scientific collaborations†

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