Cell growth and net Na+ flux are inhibited by a protein produced by kidney epithelial cells in culture.
Proliferation of confluent kidney epithelial cell cultures (BSC-1 line) is inhibited by a protein (Mr approximately equal to 24,000) that is secreted by the cells. The mechanism of action of this growth inhibitor was sought by studying its effect on net Na+ flux because increased availability of Na+ in the culture medium had been shown to stimulate cell growth. The increase in cell Na+ content observed during stimulation of the growth after a medium change was attenuated in the presence of the purified inhibitor. Inhibition of both cell Na+ accumulation and growth in the presence of the protein was reversed completely by addition of NaCl to the medium. These results suggest that control of net Na+ flux and growth in kidney epithelial cells could be mediated, at least in part, by a secreted cellular protein.
D000818:Animals; D001693:Biological Transport, Active; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004848:Epithelium / Q000502:physiology; D007668:Kidney / Q000502:physiology*; D007700:Kinetics; D011506:Proteins / Q000302:isolation & purification* / Q000502:physiology; D012964:Sodium / Q000378:metabolism*
D011506:Proteins; D012964:Sodium