Essential Role of Neural Wiskott-Aldrich Syndrome Protein in Neurite Extension in PC12 Cells and Rat Hippocampal Primary Culture Cells

• Published in: The Journal of biological chemistry 2000-04, Vol.275 (16), p.11987-11992
• Main Authors: Banzai, Yoshifumi, Miki, Hiroaki, Yamaguchi, Hideki, Takenawa, Tadaomi
• Format: Article
• Language: English
• Subjects: Actin Depolymerizing Factors; Amino Acid Sequence; Animals; Arp2 protein; Arp3 protein; cdc42 protein; Cells, Cultured; cofilin; Cyclic AMP - metabolism; Hippocampus - growth & development; Microfilament Proteins - chemistry; Molecular Sequence Data; Mutagenesis, Site-Directed; Neural Wiskott-Aldrich syndrome protein; Neurites - physiology; PC12 Cells; Proteins - genetics; Proteins - physiology; Rats; Sequence Homology, Amino Acid; Structure-Activity Relationship; verprolin; Wiskott-Aldrich Syndrome - metabolism; Wiskott-Aldrich Syndrome Protein
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.275.16.11987

Neural Wiskott-Aldrich syndrome protein (N-WASP) is an actin-regulating protein that induces filopodium formation downstream of Cdc42. It has been shown that filopodia actively extend from the growth cone, a guidance apparatus located at the tip of neurites, suggesting their role in neurite extension. Here we examined the possible involvement of N-WASP in the neurite extension process. Since verprolin, cofilin homology andacidic region (VCA) of N-WASP is known to be required for the activation of Arp2/3 complex that induces actin polymerization, we prepared a mutant (Δcof) lacking four amino acid residues in the cofilin homology region. The corresponding residues in WASP had been reported to be mutated in some Wiskott-Aldrich syndrome patients. Expression of Δcof N-WASP suppressed neurite extension of PC12 cells. In support of this, the VCA region of Δcof cannot activate Arp2/3 complex enough compared with wild-type VCA. Furthermore, H208D mutant, which has been shown unable to bind to Cdc42, also works as a dominant negative mutant in neurite extension assay. Interestingly, the expression of H208D-Δcof double mutant has no significant dominant negative effect. Finally, the expression of the Δcof mutant also severely inhibited the neurite extension of primary neurons from rat hippocampus. Thus, N-WASP is thought to be a general regulator of the actin cytoskeleton indispensable for neurite extension, which is probably caused through Cdc42 signaling and Arp2/3 complex-induced actin polymerization.