JNK phosphorylation of paxillin, acting through the Rac1 and Cdc42 signaling cascade, mediates neurite extension in N1E-115 cells.

Abstract

Neurons extend neurites from the cell body before formation of the polarized processes of an axon and dendrites. Neurite outgrowth involves remodeling of the cytoskeletal components, which are initially regulated by small GTPases of the Rho family. Here we show that c-Jun N-terminal kinase (JNK), which is controlled by Rho GTPases Rac1 and Cdc42, is activated following neurite extension in mouse N1E-115 neuroblastoma cells as a model. The extension is inhibited by JNK inhibitors (SP600125 and the small JNK-binding peptide) and Clostridium difficile Toxin B, the inhibitor for Rho GTPases. Additionally, paxillin, the multifunctional focal adhesion protein, is phosphorylated at Ser 178 by upregulation of the Rac1/Cdc42/JNK cascade. Conversely, transfection of the paxillin construct harboring the Ser 178-to-Ala mutation into cells inhibits neurite extension. Taken together, these results suggest the novel role of the Rac1/Cdc42/JNK signaling cascade in neurite extension and indicate that the downstream target paxillin may be one of the convergent points of various signaling pathways underlying neurite extension.

• Authors: Junji Yamauchi, Yuki Miyamoto, Atsushi Sanbe, Akito Tanoue
• Journal: Experimental cell research (Exp Cell Res) Vol. 312 Issue 15 Pg. 2954-61 (Sep 10 2006) ISSN: 0014-4827 [Print] United States
• PMID: 16814769 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Paxillin
• Recombinant Fusion Proteins
• JNK Mitogen-Activated Protein Kinases
• cdc42 GTP-Binding Protein
• rac1 GTP-Binding Protein

Topics

• Animals
• Cell Line, Tumor
• Fluorescent Antibody Technique
• JNK Mitogen-Activated Protein Kinases (metabolism)
• Mice
• Neurites (enzymology, ultrastructure)
• Neuroblastoma (metabolism)
• Paxillin (metabolism)
• Phosphorylation
• Recombinant Fusion Proteins (genetics, metabolism)
• Signal Transduction
• Transfection
• cdc42 GTP-Binding Protein (metabolism)
• rac1 GTP-Binding Protein (metabolism)