Our recent studies have shown that extracellular-regulated protein kinase (ERK) promotes cell death in cerebellar granule neurons (CGN) cultured in low potassium. Here we report that the “death” phenotypes of CGN after potassium withdrawal are heterogeneous, allowing the distinction between plasma membrane (PM)–, DNA-, and PM/DNA-damaged populations. These damaged neurons display nuclear condensation that precedes PM or DNA damage. Inhibition of ERK activation either by U0126 or by dominant-negative mitogen-activated protein kinase/ERK kinase (MEK) overexpression results in a dramatic reduction of PM damaged neurons and nuclear condensation. In contrast, overexpression of constitutively active MEK potentiates PM damage and nuclear condensation. ERK-promoted cellular damage is independent of caspase-3. Persistent active ERK translocates to the nucleus, whereas caspase-3 remains in the cytoplasm. Antioxidants that reduced ERK activation and PM damage showed no effect on caspase-3 activation or DNA damage. These data identify ERK as an important executor of neuronal damage involving a caspase-3–independent mechanism.
ERK activation promotes neuronal degeneration predominantly through plasma membrane damage and independently of caspase-3
The online version of this article includes supplemental material.
Abbreviations used in this paper: Ac-DEVD-CHO, acetyl-Asp-Glu-Val-Asp-aldehyde; CA, constitutively active; CGN, cerebellar granule neuron; CHX, cyclohexamide; CN, condensed nuclei; DN, dominant-negative; Egr-1, early growth response gene-1; ERK, extracellular-regulated protein kinase; JNK, c-Jun NH2-terminal kinase; MEK, MAPK/ERK kinase; MOI, multiplicity of infection; N-AC, N-acetyl cysteine; pERK, persistent active ERK; PI, propidium iodide; PM, plasma membrane; ROS, reactive oxygen species; SOD, superoxide dismutase; Z-VAD-FMK, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone.
Srinivasa Subramaniam, Ute Zirrgiebel, Oliver von Bohlen und Halbach, Jens Strelau, Christine Laliberté, David R. Kaplan, Klaus Unsicker; ERK activation promotes neuronal degeneration predominantly through plasma membrane damage and independently of caspase-3 . J Cell Biol 10 May 2004; 165 (3): 357–369. doi: https://doi.org/10.1083/jcb.200403028
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