Essential role of neural Wiskott-Aldrich syndrome protein in neurite extension in PC12 cells and rat hippocampal primary culture cells.
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 and acidic 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 (Deltacof) 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 Deltacof N-WASP suppressed neurite extension of PC12 cells. In support of this, the VCA region of Deltacof 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-Deltacof double mutant has no significant dominant negative effect. Finally, the expression of the Deltacof 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.
Banzai
Y
Y
Department of Biochemistry, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108, Japan.
Miki
H
H
Yamaguchi
H
H
Takenawa
T
T
D051339:Actin Depolymerizing Factors; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006624:Hippocampus / Q000254:growth & development*; D008840:Microfilament Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016501:Neurites / Q000502:physiology*; D016716:PC12 Cells; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014923:Wiskott-Aldrich Syndrome / Q000378:metabolism*; D051316:Wiskott-Aldrich Syndrome Protein
D051339:Actin Depolymerizing Factors; D008840:Microfilament Proteins; D011506:Proteins; C495769:Was protein, rat; D051316:Wiskott-Aldrich Syndrome Protein; D000242:Cyclic AMP