Expression of the surface antigen 4F2hc affects system-L-like neutral-amino-acid-transport activity in mammalian cells.
Mammalian cells possess a variety of amino acid-transport systems with overlapping substrate specificity. System L is one of the major amino acid-transport systems of non-epithelial cells. By expression cloning we have recently demonstrated that the surface antigen 4F2hc (CD98) is a necessary component for expression of system-L-like amino acid-transport activity in C6-BU-1 rat glioma cells [Bröer, Bröer and Hamprecht (1995) Biochem. J. 312, 863-870]. 4F2hc mRNA was detected in CHO cells, COS cells, activated lymphocytes isolated from mouse spleen and primary cultures of astrocytes. In all these cell types, Na+-independent isoleucine transport was mediated by system L. No contribution of system y+L to isoleucine or arginine transport was detected in C6-BU-1 cells. In lymphocytes, both system-L-like amino acid-transport activity and 4F2hc mRNA levels increased after treatment with phorbol ester plus ionomycin. Antisense oligonucleotides caused modest inhibition of Na+-independent isoleucine transport in C6-BU-1 cells and primary cultures of astroglial cells, whereas arginine transport was unaffected. Overexpression of 4F2hc cDNA in CHO cells resulted in an increase in Na+-independent isoleucine transport.
Bröer
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S
Physiologisch-chemisches Institut der Universität, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany.
Bröer
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A
Hamprecht
B
B
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D001120:Arginine / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism; D001692:Biological Transport; D001921:Brain / Q000166:cytology; D016466:CHO Cells; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics; D027261:Fusion Regulatory Protein-1; D005910:Glioma / Q000473:pathology; D007532:Isoleucine / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D008322:Mammals / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D016415:Sequence Alignment; D017385:Sequence Homology; D014162:Transfection; D014407:Tumor Cells, Cultured
D000596:Amino Acids; D015703:Antigens, CD; D002352:Carrier Proteins; D018076:DNA, Complementary; D027261:Fusion Regulatory Protein-1; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D007532:Isoleucine; D001120:Arginine