Zinc induces ERK-dependent cell death through a specific Ras isoform.
The effect of Zn on p53-independent cell death was examined in IIC9 embryonic fibroblasts. Despite the fact that these cells are p53-minus, Zn-mediated death occurs via an apoptotic mechanism. Death is facilitated by the presence of the Zn ionophore, pyrithione, indicating that intracellular Zn initiates the death response. Our investigations of the mechanism of Zn action demonstrate that Zn induces the death of IIC9 cells in a manner that is ERK-dependent. Expression of dn-(dominant negative)Ras attenuates ERK1/2 activation by Zn, and correspondingly reduces its cytotoxic effects. Raf-RBD pull-down experiments confirm that Zn treatment activates Ras and identified H-Ras as the specific isoform activated. This contrasts the activation of N-Ras that occurs when IIC9 cells are stimulated with thrombin. Thus, although the prolonged activation of the Ras/ERK pathway by Zn is similar to that seen when induced by mitogen, the distinguishing feature appears to be the isoform specificity of Ras activation.
Klein
Claudette
C
Department of Biochemistry and Molecular Biology, School of Medicine, Saint Louis University, Saint Louis, MO, USA. kleinc@slu.edu
Creach
Kimberly
K
Irintcheva
Virginia
V
Hughes
Katherine J
KJ
Blackwell
Penny Lane
PL
Corbett
John A
JA
Baldassare
Joseph J
JJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002712:Chlorides / Q000633:toxicity; D006224:Cricetinae; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D011905:Genes, ras; D007476:Ionophores / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D013871:Thiones / Q000494:pharmacology; D014162:Transfection; D015032:Zinc / Q000378:metabolism*; D017967:Zinc Compounds / Q000633:toxicity
D002712:Chlorides; D007476:Ionophores; D020033:Protein Isoforms; D011725:Pyridines; D013871:Thiones; D017967:Zinc Compounds; C008704:pyrithione; C016837:zinc chloride; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D016283:Proto-Oncogene Proteins p21(ras); D015032:Zinc