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Fig. 2 | Molecular Brain

Fig. 2

From: AMP-activated protein kinase contributes to zinc-induced neuronal death via activation by LKB1 and induction of Bim in mouse cortical cultures

Fig. 2

AMP-independent activation of AMPK in zinc neurotoxicity. a Representative western blot (left) and quantitation (right) results to document phosphorylation of AMPK over the time-course of zinc treatment. Protein samples were prepared from near-pure neuronal cultures at the indicated time points after 10 min exposure to 300 μM zinc. Actin was used as loading control. Graph data depict the mean ± SEM levels of AMPK phosphorylation of threonine residues (T183 in α-1/T172 in α-2) normalized to actin and are expressed as a percent of control levels (n = 3/group, *p < 0.05 compared to sham controls, two-tailed t-test). Whereas noticeable AMPK phosphorylation on serine residues was not detected, AMPK phosphorylation on threonine residues (T183 in α-1/T172 in α-2) was detected beginning 2 h after zinc treatment. b Intracellular AMP/ATP ratio over the time-course of zinc treatment (300 μM for 10 min). A significant increase in AMP/ATP ratio was detected beginning 4 h after zinc treatment. **p < 0.01 compared to sham controls, two-tailed t-test. c AMPK enzyme activity assay performed using recombinant AMPK-α2 protein with or without zinc (1 μM) (mean ± SEM, n = 4). In vitro AMPK enzyme activity was not directly affected by zinc treatment. d Representative western blots and quantitation of the phosphorylation of AMPK (n = 3/group). Protein samples were prepared from near-pure neuronal cultures at 2 h after 300 μM zinc for 10 min with or without 2 mM nicotinamide (NAM), a chemical inhibitor of PARP. The activation of AMPK at 2 h was not attenuated by NAM

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