Article: article from journal or magazin.
c-Jun N-terminal kinase-3 (JNK3)/stress-activated protein kinase-beta (SAPKbeta) binds and phosphorylates the neuronal microtubule regulator SCG10.
Publication types: Journal Article
The neuronal growth-associated protein SCG10 is enriched in the growth cones of neurons where it destabilizes microtubules and thus contributes to the dynamic assembly and disassembly of microtubules. Since its microtubule-destabilizing activity is regulated by phosphorylation, SCG10 may link extracellular signals to rearrangements of the neuronal cytoskeleton. To identify signal transduction pathways that may lead to SCG10 phosphorylation, we tested a series of serine-threonine-directed protein kinases that phosphorylate SCG10 in vitro. We demonstrate that purified SCG10 can be phosphorylated by two subclasses of mitogen-activated protein (MAP) kinases, c-Jun N-terminal/stress-activated protein kinase (JNK/SAPK) and p38 MAP kinase. Moreover, SCG10 was found to bind tightly and specifically to JNK3/SAPKbeta. JNK3/SAPKbeta phosphorylation occurs at Ser-62 and Ser-73, residues that result in reduced microtubule-destabilizing activity for SCG10. Endogenous SCG10 also undergoes increased phosphorylation in sympathetic neurons at times of JNK3/SAPKbeta activation following deprivation from nerve growth factor. Together these observations indicate that activation of JNK/SAPKs provides a pathway for phosphorylation of SCG10 and control of growth cone microtubule formation following neuronal exposure to cellular stresses.
Amino Acid Sequence, Amino Acids/analysis, Animals, Blotting, Western, COS Cells, Carrier Proteins, Growth Cones/metabolism, Intracellular Signaling Peptides and Proteins, MAP Kinase Signaling System, Mass Spectrometry, Membrane Proteins, Mice, Mitogen-Activated Protein Kinase 10, Mitogen-Activated Protein Kinase Kinases/metabolism, Mitogen-Activated Protein Kinases/metabolism, Molecular Sequence Data, Nerve Growth Factors/chemistry, Nerve Growth Factors/metabolism, Phosphorylation, Protein Binding, Protein-Tyrosine Kinases/metabolism, Rats, Rats, Sprague-Dawley, Substrate Specificity, p38 Mitogen-Activated Protein Kinases
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