The Binding Specificity of Amino Acid Transport System y + L in Human Erythrocytes is Altered by Monovalent Cations

1996 ◽  
Vol 153 (1) ◽  
pp. 37-44 ◽  
Author(s):  
S. Angelo ◽  
C. Irarrázabal ◽  
R. Devés
Keyword(s):  
Amino Acid ◽  
Transport System ◽  
Amino Acid Transport ◽  
Binding Specificity ◽  
Human Erythrocytes ◽  
Monovalent Cations ◽  
Acid Transport ◽  
Amino Acid Transport System

Osmotic Regulation of ATA2 mRNA Expression and Amino Acid Transport System A Activity

2001 ◽  
Vol 283 (1) ◽  
pp. 174-178 ◽  
Author(s):  
Roberta R. Alfieri ◽  
Pier-Giorgio Petronini ◽  
Mara A. Bonelli ◽  
Alessandro E. Caccamo ◽  
Andrea Cavazzoni ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mrna Expression ◽  
Transport System ◽  
Amino Acid Transport ◽  
Osmotic Regulation ◽  
Acid Transport ◽  
Amino Acid Transport System ◽  
System A

Expression and regulation of 4F2hc and hLAT1 in human trophoblasts

2002 ◽  
Vol 282 (1) ◽  
pp. C196-C204 ◽  
Author(s):  
Yoko Okamoto ◽  
Masahiro Sakata ◽  
Kazuhiro Ogura ◽  
Toshiya Yamamoto ◽  
Masaaki Yamaguchi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Line ◽  
Transport System ◽  
Human Placenta ◽  
Amino Acid Transport ◽  
Calcium Ionophore ◽  
Acid Transport ◽  
Amino Acid Transport System ◽  
System L ◽  
Choriocarcinoma Cell Line

The neutral amino acid transport system L is a sodium-independent transport system in human placenta and choriocarcinoma cells. Recently, it was found that the heterodimer composed of hLAT1 (a light-chain protein) and 4F2 heavy chain (4F2hc), a type II transmembrane glycoprotein, is responsible for system L amino acid transport. We found that the mRNAs of 4F2hc and hLAT1 were expressed in the human placenta and a human choriocarcinoma cell line. The levels of the 4F2hc and hLAT1 proteins in the human placenta increased at full term compared with those at midtrimester. Immunohistochemical data showed that these proteins were localized mainly in the placental apical membrane. Data from leucine uptake experiments, Northern blot analysis, and immunoblot analysis showed that this transport system was partially regulated by protein kinase C and calcium ionophore in the human choriocarcinoma cell line. Our results suggest that the heterodimer of 4F2hc and hLAT1 may play an important role in placental amino acid transport system L.

Cloning and functional characterization of a new subtype of the amino acid transport system N

2001 ◽  
Vol 281 (6) ◽  
pp. C1757-C1768 ◽  
Author(s):  
Takeo Nakanishi ◽  
Ramesh Kekuda ◽  
You-Jun Fei ◽  
Takahiro Hatanaka ◽  
Mitsuru Sugawara ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Amino Acid Transport ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Isobutyric Acid ◽  
Xenopus Laevis Oocytes ◽  
Acid Transport ◽  
Amino Acid Transport System

We have cloned a new subtype of the amino acid transport system N2 (SN2 or second subtype of system N) from rat brain. Rat SN2 consists of 471 amino acids and belongs to the recently identified glutamine transporter gene family that consists of system N and system A. Rat SN2 exhibits 63% identity with rat SN1. It also shows considerable sequence identity (50–56%) with the members of the amino acid transporter A subfamily. In the rat, SN2 mRNA is most abundant in the liver but is detectable in the brain, lung, stomach, kidney, testis, and spleen. When expressed in Xenopus laevis oocytes and in mammalian cells, rat SN2 mediates Na+-dependent transport of several neutral amino acids, including glycine, asparagine, alanine, serine, glutamine, and histidine. The transport process is electrogenic, Li+tolerant, and pH sensitive. The transport mechanism involves the influx of Na+ and amino acids coupled to the efflux of H+, resulting in intracellular alkalization. Proline, α-(methylamino)isobutyric acid, and anionic and cationic amino acids are not recognized by rat SN2.

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