Characterization of amino acid transport system L in HTB-41 human salivary gland epidermoid carcinoma cells.
BACKGROUND
The amino acid transport system L is a major nutrient transport system that is responsible for transport of neutral amino acids, including several essential amino acids. The current study attempted to investigate the expression and functional characterization of amino acid transport system L in HTB-41 human submaxillary salivary gland epidermoid carcinoma cells.


METHODS
RT-PCR analysis, Western blot analysis and amino acid transport measurements were used.


RESULTS
The HTB-41 cells expressed the L-type amino acid transporter 1 (LAT1) together with its associating protein heavy chain of 4F2 antigen (4F2hc) in the plasma membrane, whereas the HTB-41 cells did not express the L-type amino acid transporter 2 (LAT2). The uptakes of [14C]L-leucine were Na+-independent and completely inhibited by a system L selective inhibitor, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). The affinity of [14C]L-leucine uptake and the inhibition profile of [14C]L-leucine uptake by various L-amino acids in the HTB-41 cells were comparable with those for the LAT1 expressed in Xenopus oocytes.


CONCLUSIONS
The transport of neutral amino acids including several essential amino acids into the HTB-41 human submaxillary salivary gland epidermoid carcinoma cells are mediated by LAT1.
Park
No-Seung
NS
Oral Biology Research Institute and The second stage of BK21, Chosun University College of Dentistry, Gwangju 501-759, Korea.
Kim
Su-Gwan
SG
Kim
Hak-Kyun
HK
Moon
Seong-Yong
SY
Kim
Chun Sung
CS
Cho
Seon-Ho
SH
Kanai
Yoshikatsu
Y
Endou
Hitoshi
H
Kim
Do Kyung
DK
D027062:Amino Acid Transport System L / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D015153:Blotting, Western; D002250:Carbon Radioisotopes; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D045744:Cell Line, Tumor; D006801:Humans; D007930:Leucine / Q000378:metabolism / Q000493:pharmacokinetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012468:Salivary Gland Neoplasms / Q000378:metabolism*; D013363:Submandibular Gland / Q000378:metabolism / Q000473:pathology
D027062:Amino Acid Transport System L; D000598:Amino Acids, Cyclic; D002250:Carbon Radioisotopes; C006504:2-aminobicyclo(2,2,1)heptane-2-carboxylic acid; D007930:Leucine