The non-receptor-protein tyrosine kinase c-Src is overexpressed and activated in a large number of human cancers, in which it is associated with tumor development and progression. Canonical regulation takes place by means of an alternative phosphorylation of tyrosine residues -- Tyr419 for activation and Tyr530 for inactivation. An independent redox regulation mechanism, involving cysteine residues, has also been proposed, in which oxidation activates the enzyme. Here we present a kinetic analysis of the effect of N-acetyl-l-cysteine (NAC) on c-Src, demonstrating that reduction reverts the oxidation-driven activation. In cancer cells, we show that NAC treatment produces an increase in specifically labeled reduced thiols of c-Src cysteines, thus confirming a redox transition. In addition to a decrease in Tyr419 phosphorylation, this leads to a massive shift of c-Src from plasma membranes -- where its active form is located -- to endolysosomal compartments. With the objective of deciphering the complex issue of c-Src regulation and of devising new strategies to revert its activation in cancers, redox regulation thus emerges as a promising area for study.
N-acetyl-l-cysteine fosters inactivation and transfer to endolysosomes of c-Src / Ewa K., Krasnowska; E., Pittalluga; Anna Maria, Brunati; Brunelli, Roberto; Graziella, Costa; Marco De, Spirito; Annalucia, Serafino; Fulvio, Ursini; Tiziana, Parasassi. - In: FREE RADICAL BIOLOGY & MEDICINE. - ISSN 0891-5849. - 45:11(2008), pp. 1566-1572. [10.1016/j.freeradbiomed.2008.09.012]
N-acetyl-l-cysteine fosters inactivation and transfer to endolysosomes of c-Src
BRUNELLI, Roberto;
2008
Abstract
The non-receptor-protein tyrosine kinase c-Src is overexpressed and activated in a large number of human cancers, in which it is associated with tumor development and progression. Canonical regulation takes place by means of an alternative phosphorylation of tyrosine residues -- Tyr419 for activation and Tyr530 for inactivation. An independent redox regulation mechanism, involving cysteine residues, has also been proposed, in which oxidation activates the enzyme. Here we present a kinetic analysis of the effect of N-acetyl-l-cysteine (NAC) on c-Src, demonstrating that reduction reverts the oxidation-driven activation. In cancer cells, we show that NAC treatment produces an increase in specifically labeled reduced thiols of c-Src cysteines, thus confirming a redox transition. In addition to a decrease in Tyr419 phosphorylation, this leads to a massive shift of c-Src from plasma membranes -- where its active form is located -- to endolysosomal compartments. With the objective of deciphering the complex issue of c-Src regulation and of devising new strategies to revert its activation in cancers, redox regulation thus emerges as a promising area for study.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.