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Regulation of active amino acid transport by growth-related changes in membrane potential in a human fibroblast

Journal Article · · J. Biol. Chem.; (United States)
OSTI ID:6505286
Indirect measurements of membrane potential in human diploid fibroblast cells indicate that there is a growth-related difference in membrane potential between subconfluent, growing cells (-49 mV) and serum-deprived, quiescent cells (-22 mV). The elevated membrane potential in growing cells appears to be solely responsible for the 2-fold higher ..cap alpha..-aminoisobutyric acid accumulating capacity that we observed previously in growing cells, as compared to quiescent cells. When the membrane potentials of quiescent and growing cells are set equal, using valinomycin and varying (K/sup +/)/sub 0/, ..cap alpha..-aminoisobutyric acid accumulation is dependent on the magnitude of the potential, but it is independent of the growth state of the cell. The data indicate that both the accumulation of ..cap alpha..-aminoisobutyric acid in human diploid fibroblast cells and the K/sub m/ for its transport are sensitive to experimentally induced changes in membrane potential, and furthermore, that the observed growth-related difference in membrane potential between growing and quiescent cells can account for their growth-associated differences in ..cap alpha..-aminoisobutyric acid accumulation and K/sub m/.
Research Organization:
Oak Ridge National Lab., TN
OSTI ID:
6505286
Journal Information:
J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 253:22; ISSN JBCHA
Country of Publication:
United States
Language:
English