N-acetyl-l-cysteine fosters inactivation and transfer to endolysosomes of c-Src.
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.
Istituto di Neurobiologia e Medicina Molecolare, CNR, Rome, Italy.
Ewa K
EK
Krasnowska
Eugenia
E
Pittaluga
Anna Maria
AM
Brunati
Roberto
R
Brunelli
Graziella
G
Costa
Marco
M
De Spirito
Annalucia
A
Serafino
Fulvio
F
Ursini
Tiziana
T
Parasassi
D000111:Acetylcysteine / Q000737:chemistry* / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D000081247:CSK Tyrosine-Protein Kinase; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D047468:Immunoprecipitation; D007700:Kinetics; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D018613:Microscopy, Confocal; D010084:Oxidation-Reduction / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D019061:src-Family Kinases
D016166:Free Radical Scavengers; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D000111:Acetylcysteine