L-serine uptake by human placental microvillous membrane vesicles

Lewis, R.M., Glazier, J., Greenwood, S.L., Bennett, E.J., Godfrey, K.M., Jackson, A.A., Sibley, C.P., Cameron, I.T. and Hanson, M.A. (2007) L-serine uptake by human placental microvillous membrane vesicles. Placenta, 28, (5-6), 445-452. (doi:10.1016/j.placenta.2006.06.014).


Full text not available from this repository.


The human fetus requires more glycine than any other amino acid but placental glycine transfer to the fetus is insufficient to meet fetal demand. L-Serine could represent a major metabolic source of glycine for the human fetus but little is known about the kinetics and physiology of L-serine uptake by the human placenta. We have characterised the amino acid transport systems involved in the uptake of L-serine by the microvillous membrane of the human placental syncytiotrophoblast and compared the uptake rates to those of glycine. L-Serine uptake into microvillous membrane (MVM) vesicles was primarily mediated by system A (MeAIB inhibitable) and system L (BCH inhibitable). Further characterisation using specific substrates of LAT1 and LAT2 found the pattern of L-serine uptake was consistent with that expected for uptake mediated by LAT2. Uptakes were performed with tracer levels of (14)C-L-serine, physiological levels of L-serine, or with physiological levels of amino acids. As amino acid concentrations rose, the proportion of uptake by System L decreased while uptake by uncharacterised Na(+)-independent systems increased. Uptake of Lserine into MVM vesicles had a V(max) of 2.1+/-0.4 nmol/mg protein/min, which was significantly higher than for glycine (V(max) 1.0+/-0.2 nmol/mg protein/min). This indicates that MVM vesicles have a higher uptake capacity for L-serine than glycine, despite a greater demand for glycine over serine for fetal protein synthesis. Further studies are now required to define the fate of L-serine taken up by the placenta and its importance for the fetus.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1016/j.placenta.2006.06.014
ISSNs: 0143-4004 (print)
Related URLs:
Keywords: acid, antigens, health, sodium-calcium exchanger, pregnancy, amino acid transport system a, amino acid transport system y+, glycine, kinetics, origins, cd98 light chains, genetics, biological transport, fetus, disease, female, amino acids, microvilli, serine, placenta, human, amino acid transport system y+l, research, neoplasm proteins, fetal, proteins, protein, physiology, metabolism, amino acid transport systems, humans, membrane
Subjects: R Medicine > RG Gynecology and obstetrics
Q Science > QH Natural history > QH301 Biology
Divisions : University Structure - Pre August 2011 > School of Medicine
ePrint ID: 61327
Accepted Date and Publication Date:
May 2007Published
Date Deposited: 10 Sep 2008
Last Modified: 31 Mar 2016 12:44
URI: http://eprints.soton.ac.uk/id/eprint/61327

Actions (login required)

View Item View Item