Regulation of amino acid transport in the renal epithelial cell line NBL-1.

The activities of the transport systems A, B° and XAG- are induced by various forms of stress in renal epithelial cells. Amino acid deprivation induces System A and XAG- in a protein-synthesis dependent process. In the case of System XAG- evidence is presented that induction of transport does not involve an increase in the amount of mRNA for the transporter or of the amount of transport protein. Preliminary evidence for the existence of a novel glycoprotein which is induced in parallel to the induction of these transport systems is presented. It is suggested that the induction of amino acid transport proteins and of some of the so-called stress proteins may be triggered by a common molecular mechanism.