Characterization of a BALB/c 3T3 preadipose cell mutant with altered Na+K+Cl- cotransport activity.
A BALB/c 3T3 cell mutant (3T3-E12) was isolated by its ability to survive at a low extracellular K+ concentration (0.14 mM). The growth rate of mutant cells was less dependent on external K+ than parental cells. Analysis of potassium transport revealed that 3T3-E12 cells have a decreased activity of the furosemide-sensitive Na+K+Cl- cotransport system, both in the efflux and influx modes. This is shown to be a result of a decrease in the apparent affinity of the transport system for K+ and Na+, but not Cl-. Upon exposure to the phorbol ester 12-0-tetradecanoyl-phorbol-13-acetate (TPA), BALB/c 3T3 cells exhibited a maximal volume decrease of 20%, while mutant cells shrunk by only 7%, suggesting that regulation of cell volume, at least four exposure to a tumor promoter, is impaired in mutant cells compared to parental 3T3 cells.
D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002455:Cell Division; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism*; D005665:Furosemide / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C / Q000235:genetics*; D009154:Mutation; D011188:Potassium / Q000378:metabolism*; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002712:Chlorides; D005665:Furosemide; D012964:Sodium; D012413:Rubidium; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium