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| N-WASp | |
|---|---|
| Name | Neural Wiskott–Aldrich syndrome protein |
| Uniprot | P42768 |
| Organism | Homo sapiens |
| Length | ~505 aa (isoforms vary) |
| Gene location | Chromosome 7q31.2 |
N-WASp N-WASp is a ubiquitously expressed actin-regulatory protein central to Arp2/3-mediated actin polymerization in metazoan cells. It integrates signals from Rho-family GTPases, phosphoinositides, and SH3-containing adaptors to nucleate branched actin networks, influencing processes from endocytosis to cell migration. N-WASp function has been characterized through genetic, biochemical, and imaging studies across model organisms and human cell lines.
N-WASp was discovered through comparative studies of the Wiskott–Aldrich syndrome protein family in mammals and was biochemically linked to the Arp2/3 complex, the Rho GTPase Cdc42, and phosphatidylinositol 4,5-bisphosphate. Key early work involved laboratories associated with David G. Drubin, Ralf F. Ketelaar, Tony Pawson, Michael L. Dustin, Timothy J. Mitchison and institutions such as Harvard University, Massachusetts Institute of Technology, European Molecular Biology Laboratory, Rockefeller University and Max Planck Society. Subsequent genetic and proteomic mapping implicated N-WASp in neuronal morphogenesis studied at Salk Institute, Cold Spring Harbor Laboratory, and University of California, San Francisco.
N-WASp contains an N-terminal WH1 (or EVH1-like) domain, a GTPase-binding domain (GBD), a proline-rich region (PRR) with multiple SH3-binding motifs, and a C-terminal VCA (verprolin-homology, central, acidic) domain that directly activates the Arp2/3 complex. Structural details were resolved using methods pioneered by groups at European Synchrotron Radiation Facility, Stanford University, and Max Planck Institute of Biochemistry, with contributions from crystallographers such as Nico Tiedtke and Gerhard Grüber. Domain interactions with partners were mapped by researchers at University College London, Imperial College London, Johns Hopkins University, and University of Cambridge.
N-WASp is autoinhibited via intramolecular interaction between the GBD and the VCA domain; activation requires relief of this autoinhibition by binding of activated Cdc42 (protein), engagement with phosphatidylinositol 4,5-bisphosphate, or multivalent SH3-mediated interactions. Activated N-WASp exposes the VCA motif to recruit the Arp2/3 complex, promoting nucleation of branched actin filaments and polymerization. Biochemical reconstitution performed at facilities including Rockefeller University, Max Planck Institute, MRC Laboratory of Molecular Biology, and Wadsworth Center clarified kinetics of nucleation and pointed to regulation by phosphorylation events studied at Yale University and University of Pennsylvania.
N-WASp controls clathrin-mediated endocytosis, filopodia and lamellipodia dynamics, podosome and invadopodium formation, and synaptic spine morphogenesis. Cell biological roles were elucidated in systems ranging from primary neurons at Columbia University to immune cells at Stanford University School of Medicine and epithelial models at University of Chicago. Regulation occurs via phosphorylation by kinases such as Src family kinases, PAK1, and CK2; dephosphorylation by phosphatases including PTEN-associated complexes; and ubiquitination pathways characterized by research groups at University of California, San Diego and Broad Institute. Crosstalk with membrane trafficking proteins was identified in studies at University of Toronto and Monash University.
N-WASp contributes to neuronal development, axon guidance, dendritic spine maturation, and neural crest cell migration investigated at University of Oxford, Columbia University Medical Center, and Mount Sinai Health System. Dysregulation has been implicated in neurodevelopmental disorders studied at Stanford School of Medicine and cancer cell invasion and metastasis researched at Memorial Sloan Kettering Cancer Center, Dana-Farber Cancer Institute, and MD Anderson Cancer Center. Somatic mutations and altered expression were profiled in datasets curated by The Cancer Genome Atlas, International Cancer Genome Consortium, and consortia based at Sanger Institute. Links to immunodeficiency syndromes, similar to Wiskott–Aldrich syndrome work at National Institutes of Health, were explored to distinguish roles of WASP family members.
N-WASp interacts with a network of proteins including the Arp2/3 complex subunits characterized at EMBL-EBI, SH3-domain proteins such as Nck, Grb2, and Intersectin mapped by groups at University of California, Berkeley and ETH Zurich, scaffolds like Cortactin and WIPF1, and small GTPases Cdc42 (protein), Rac1, and regulators including GEFs and GAPs studied at Institute Pasteur and Max Planck Institute for Biology of Ageing. N-WASp participates in signaling cascades downstream of receptor tyrosine kinases such as EGFR and PDGFR, integrin complexes involving FAK and Talin, and immune receptors investigated at Rockefeller University Hospital and Karolinska Institutet.
Experimental approaches include X-ray crystallography and cryo-electron microscopy carried out at Argonne National Laboratory and EMBL Hamburg, single-molecule TIRF microscopy from labs at University of California, San Diego and École Polytechnique Fédérale de Lausanne, and live-cell imaging with super-resolution techniques developed at Howard Hughes Medical Institute and Janelia Research Campus. Gene editing using CRISPR-Cas9 at Broad Institute, RNAi screens at Wellcome Sanger Institute, proteomics by mass spectrometry at Max Planck Institute for Biophysical Chemistry, and in vivo models in Mus musculus, Danio rerio, and Drosophila melanogaster have all contributed to current understanding. Biochemical reconstitutions of actin nucleation used reagents and protocols standardized by consortia at Addgene and methodologies from Cold Spring Harbor Laboratory.
Category:Actin-binding proteins