title: Dyrk1A negatively regulates the actin cytoskeleton through threonine phosphorylation of N-WASP.
abstract: Neural Wiskott-Aldrich syndrome protein (N-WASP) is involved in tight regulation of actin polymerization and dynamics. N-WASP activity is regulated by intramolecular interaction, binding to small GTPases and tyrosine phosphorylation. Here, we report on a novel regulatory mechanism; we demonstrate that N-WASP interacts with dual-specificity tyrosine-phosphorylation-regulated kinase 1A (Dyrk1A). In vitro kinase assays indicate that Dyrk1A directly phosphorylates the GTPase-binding domain (GBD) of N-WASP at three sites (Thr196, Thr202 and Thr259). Phosphorylation of the GBD by Dyrk1A promotes the intramolecular interaction of the GBD and verprolin, cofilin and acidic (VCA) domains of N-WASP, and subsequently inhibits Arp2/3-complex-mediated actin polymerization. Overexpression of either Dyrk1A or a phospho-mimetic N-WASP mutant inhibits filopodia formation in COS-7 cells. By contrast, the knockdown of Dyrk1A expression or overexpression of a phospho-deficient N-WASP mutant promotes filopodia formation. Furthermore, the overexpression of a phospho-mimetic N-WASP mutant significantly inhibits dendritic spine formation in primary hippocampal neurons. These findings suggest that Dyrk1A negatively regulates actin filament assembly by phosphorylating N-WASP, which ultimately promotes the intramolecular interaction of its GBD and VCA domains. These results provide insight on the mechanisms contributing to diverse actin-based cellular processes such as cell migration, endocytosis and neuronal differentiation.
authors.affiliation: Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
authors.forename: Joongkyu
authors.initials: J
authors.lastname: Park
authors.forename: Jee Young
authors.initials: JY
authors.lastname: Sung
authors.forename: Joohyun
authors.initials: J
authors.lastname: Park
authors.forename: Woo-Joo
authors.initials: WJ
authors.lastname: Song
authors.forename: Sunghoe
authors.initials: S
authors.lastname: Chang
authors.forename: Kwang Chul
authors.initials: KC
authors.lastname: Chung
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003712:Dendrites / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010769:Phosphothreonine / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000378:metabolism; D051381:Rats; D051316:Wiskott-Aldrich Syndrome Protein / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D000097603:Dyrk Kinases
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D020558:GTP Phosphohydrolases; D010769:Phosphothreonine; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D051316:Wiskott-Aldrich Syndrome Protein; D020764:cdc42 GTP-Binding Protein; D000097603:Dyrk Kinases