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J Neurosci. 2013 Sep 11;33(37):14666-80. doi: 10.1523/JNEUROSCI.4821-12.2013.

c-Jun N-terminal kinase phosphorylation of heterogeneous nuclear ribonucleoprotein K regulates vertebrate axon outgrowth via a posttranscriptional mechanism.

Author information

1
Department of Biological Sciences and the Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222.

Abstract

c-Jun N-terminal kinase (JNK) mediates cell signaling essential for axon outgrowth, but the associated substrates and underlying mechanisms are poorly understood. We identified in Xenopus laevis embryos a novel posttranscriptional mechanism whereby JNK regulates axonogenesis by phosphorylating a specific site on heterogeneous nuclear ribonucleoprotein K (hnRNP K). Both JNK inhibition and hnRNP K knockdown inhibited axon outgrowth and translation of hnRNP K-regulated cytoskeletal RNAs (tau and neurofilament medium), effects that were alleviated by expressing phosphomimetic, but not phosphodeficient, forms of hnRNP K. Immunohistochemical and biochemical analyses indicated that JNK phosphorylation of hnRNP K occurred within the cytoplasm and was necessary for the translational initiation of hnRNP K-targeted RNAs but not for hnRNP K intracellular localization or RNA binding. Thus, in addition to its known roles in transcription and cytoskeletal organization, JNK acts posttranscriptionally through hnRNP K to regulate translation of proteins crucial for axonogenesis.

PMID:
24027268
PMCID:
PMC6705169
DOI:
10.1523/JNEUROSCI.4821-12.2013
[Indexed for MEDLINE]
Free PMC Article

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