Isolation and characterization of a glycine transport mutant in an established mammalian cell line, CHO(PEOT/1).
Glycine uptake in CHO(PEOT/1) cells is mediated by at least three systems, of which two have been identified and partially characterized in this study: (1) a low affinity "A" system that transports a number of small neutral amino acids including glycine and methylaminoisobutyric acid (MeAIB), and (2) a high-affinity system, specific for glycine and sarcosine. By a combination of tritium suicide and replica plating, we have isolated a mutant (CHY-3) with a 47% decrease in glycine transport at the standard test concentration of 2.5 microM. Uptake studies with radioactive glycine, MeAIB, and sarcosine revealed that the mutant lacks the glycine-sarcosine system, but has undergone a compensatory 30-50% increase in the A system. Thus, there appears to be a regulatory interaction between these two systems for glycine uptake by CHO cells.
D000621:Aminoisobutyric Acids / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005998:Glycine / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D012521:Sarcosine / Q000378:metabolism
D000621:Aminoisobutyric Acids; C017911:2-(methylamino)isobutyric acid; D005998:Glycine; D012521:Sarcosine