Abstract
c-Jun is induced in many neuronal death paradigms. A critical step in c-Jun regulation involves phosphorylation of Ser63/Ser73 located in the NH2-terminal transactivation domain. To determine the importance of this phosphorylation for neuronal apoptosis, we analyzed the sympathetic neurons of mice carrying a mutant c-Jun gene that lacks Ser63/Ser73 phosphorylation sites (jun aa). Trophic factor-deprivation or DNA damage-induced death was significantly delayed in jun aa/aa neurons. Neuronal c-Jun induction was only partially inhibited, demonstrating that phosphorylation of Ser63/73 is not required for c-Jun activation. The inductions of proapoptotic BH3-only proteins, Bim and PUMA/Bbc3, were delayed during neuronal apoptosis in mutant neurons. These results demonstrate that NH2-terminal c-Jun phosphorylation is important, but not necessary, for the induction of proapoptotic genes and neuronal apoptosis. Thus, additional JNK substrates may be critical for neuronal death. As potential mediators, we identified additional nuclear MLK/JNK substrates, including Nup214 subunit of the nuclear pore complex.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Apoptosis / physiology*
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Apoptosis Regulatory Proteins
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Bcl-2-Like Protein 11
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cells, Cultured
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DNA Damage
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Enzyme Activation
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Ganglia, Spinal / cytology
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Gene Expression Regulation
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Genes, jun
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JNK Mitogen-Activated Protein Kinases / genetics
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JNK Mitogen-Activated Protein Kinases / metabolism*
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Mutation
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Nerve Growth Factor / deficiency
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Neurons / physiology*
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Nuclear Pore / physiology*
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Nuclear Pore Complex Proteins / metabolism*
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Phosphorylation
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Protein Subunits / metabolism
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Signal Transduction
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
Substances
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Apoptosis Regulatory Proteins
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Bcl-2-Like Protein 11
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Bcl2l11 protein, mouse
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Carrier Proteins
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Membrane Proteins
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Nuclear Pore Complex Proteins
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Nup214 protein, mouse
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PUMA protein, mouse
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Protein Subunits
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Proto-Oncogene Proteins
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Tumor Suppressor Proteins
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Nerve Growth Factor
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JNK Mitogen-Activated Protein Kinases