Wiskott–Aldrich syndrome protein
PDB rendering based on 1cee.
|RNA expression pattern|
The Wiskott–Aldrich Syndrome Protein (WASp) is a 502-amino acid protein that is expressed in cells of the hematopoietic system. In the inactive state, WASp exists in an auto-inhibited conformation with sequences near its C-terminus binding to a region near its N-terminus. Its activation is dependent upon Cdc42 and PIP2 acting to disrupt this interaction causing the WASp protein to 'open'. This exposes a domain near the WASp C-Terminus that binds to and activates the Arp2/3 complex. Activated Arp2/3 nucleates new F-actin. WASp is the founding member of a gene family which also includes the broadly expressed N-WASP (neuronal Wiskott–Aldrich Syndrome protein), and Scar.
Structure and Function
The Wiskott–Aldrich syndrome (WAS) family of proteins share similar domain structure, and are involved in transduction of signals from receptors on the cell surface to the actin cytoskeleton. The presence of a number of different motifs suggests that they are regulated by a number of different stimuli, and interact with multiple proteins. Recent studies have demonstrated that these proteins, directly or indirectly, associate with the small GTPase Cdc42, known to regulate formation of actin filaments, and the cytoskeletal organizing complex, Arp2/3.
Wiskott–Aldrich syndrome is a rare, inherited, X-linked, recessive disease characterized by immune dysregulation and microthrombocytopenia, and is caused by mutations in the WAS gene. The WAS gene product is a cytoplasmic protein, expressed exclusively in hematopoietic cells, which show signalling and cytoskeletal abnormalities in WAS patients. A transcript variant arising as a result of alternative promoter usage, and containing a different 5' UTR sequence, has been described, however, its full-length nature is not known. The WASP family includes both WASP, which is expressed exclusively in hematopoietic cells, and neuronal WASP (N-WASP), which is expressed ubiquitously20. In its inactive state, N-WASP is autoinhibited and bound to Arp2/3. Cooperative binding of Cdc42 and PIP2 relieve the autoinhibition of N-WASP, causing Arp2/3 to carry out actin polymerization.
N-WASP contains an output region and a control region that are essential for its regulation. The output region is called the VCA domain. It is located towards the C-terminal end of the protein and contains three motifs: the verprolin homology motif (V) binds actin monomers and delivers them to Arp2/3; the cofilin homology motif (C) binds cofilin; and the acidic motif (A) binds Arp2/3. In isolation, the VCA region is constitutively active. However, in full-length N-WASP the control region suppresses VCA domain activity. The control region is located at N-terminal end of N-WASP. The control region contains a Cdc42 binding domain (GBP) and a PIP2 binding domain (B), both of which are critical for proper regulation of N-WASP.
In the absence of Cdc42 and PIP2, N-WASP is in an inactive, locked conformation. Cooperative binding of both Cdc42 and PIP2 relieve the autoinhibition. The cooperative binding of Cdc42 and PIP2 is thermodynamically favored; binding of one enhances binding of the other. Cdc42 and PIP2 localize the N-WASP-Arp2/3 complex to the plasma membrane. This localization ensures that the actin polymers will be able to push through the plasma membrane and form filopodium required for cell motility.
Genetic diseases associated with WASp
WASp is a product of the WAS gene and mutations in the WAS gene can lead to Wiskott–Aldrich syndrome (an X-linked disease that mainly affects males with symptoms that include thrombocytopenia, eczema, recurrent infections, and small-sized platelets). Other, less inactivating mutations affecting the WAS gene cause X-linked thrombocytopeia, or XLT.
Wiskott–Aldrich syndrome protein has been shown to interact with PLCG1, Src, NCK1, ITSN2, FGR, Grb2, PSTPIP1, CDC42, TRIP10, WIPF1, FYN, Epidermal growth factor receptor, PIK3R1, ITK and CRKL.
- "Entrez Gene: WAS Wiskott-Aldrich syndrome (eczema-thrombocytopenia)".
- Prehoda KE, Scott JA, Mullins RD, Lim WA (October 2000). "Integration of multiple signals through cooperative regulation of the N-WASP-Arp2/3 complex". Science 290 (5492): 801–6. doi:10.1126/science.290.5492.801. PMID 11052943.
- Rohatgi R, Ma L, Miki H, et al. (April 1999). "The interaction between N-WASP and the Arp2/3 complex links Cdc42-dependent signals to actin assembly". Cell 97 (2): 221–31. doi:10.1016/S0092-8674(00)80732-1. PMID 10219243.
- Banin, S; Truong O, Katz D R, Waterfield M D, Brickell P M, Gout I (August 1996). "Wiskott-Aldrich syndrome protein (WASp) is a binding partner for c-Src family protein-tyrosine kinases". Curr. Biol. 6 (8): 981–8. doi:10.1016/S0960-9822(02)00642-5. PMID 8805332.
- Finan, P M; Soames C J, Wilson L, Nelson D L, Stewart D M, Truong O, Hsuan J J, Kellie S (October 1996). "Identification of regions of the Wiskott-Aldrich syndrome protein responsible for association with selected Src homology 3 domains". J. Biol. Chem. 271 (42): 26291–5. doi:10.1074/jbc.271.42.26291. PMID 8824280.
- Krause, M; Sechi A S, Konradt M, Monner D, Gertler F B, Wehland J (April 2000). "Fyn-binding protein (Fyb)/SLP-76-associated protein (SLAP), Ena/vasodilator-stimulated phosphoprotein (VASP) proteins and the Arp2/3 complex link T cell receptor (TCR) signaling to the actin cytoskeleton". J. Cell Biol. 149 (1): 181–94. doi:10.1083/jcb.149.1.181. PMC 2175102. PMID 10747096.
- Okabe, Seiichi; Fukuda Seiji, Broxmeyer Hal E (July 2002). "Activation of Wiskott-Aldrich syndrome protein and its association with other proteins by stromal cell-derived factor-1alpha is associated with cell migration in a T-lymphocyte line". Exp. Hematol. 30 (7): 761–6. doi:10.1016/S0301-472X(02)00823-8. PMID 12135674.
- Rivero-Lezcano, O M; Marcilla A, Sameshima J H, Robbins K C (October 1995). "Wiskott-Aldrich syndrome protein physically associates with Nck through Src homology 3 domains". Mol. Cell. Biol. 15 (10): 5725–31. PMC 230823. PMID 7565724.
- McGavin, M K; Badour K, Hardy L A, Kubiseski T J, Zhang J, Siminovitch K A (December 2001). "The intersectin 2 adaptor links Wiskott Aldrich Syndrome protein (WASp)-mediated actin polymerization to T cell antigen receptor endocytosis". J. Exp. Med. 194 (12): 1777–87. doi:10.1084/jem.194.12.1777. PMC 2193569. PMID 11748279.
- She, H Y; Rockow S, Tang J, Nishimura R, Skolnik E Y, Chen M, Margolis B, Li W (September 1997). "Wiskott-Aldrich syndrome protein is associated with the adapter protein Grb2 and the epidermal growth factor receptor in living cells". Mol. Biol. Cell 8 (9): 1709–21. PMC 305731. PMID 9307968.
- Wu, Y; Spencer S D, Lasky L A (March 1998). "Tyrosine phosphorylation regulates the SH3-mediated binding of the Wiskott-Aldrich syndrome protein to PSTPIP, a cytoskeletal-associated protein". J. Biol. Chem. 273 (10): 5765–70. doi:10.1074/jbc.273.10.5765. PMID 9488710.
- Tian, L; Nelson D L, Stewart D M (March 2000). "Cdc42-interacting protein 4 mediates binding of the Wiskott-Aldrich syndrome protein to microtubules". J. Biol. Chem. 275 (11): 7854–61. doi:10.1074/jbc.275.11.7854. PMID 10713100.
- Kim, A S; Kakalis L T, Abdul-Manan N, Liu G A, Rosen M K (March 2000). "Autoinhibition and activation mechanisms of the Wiskott-Aldrich syndrome protein". Nature 404 (6774): 151–8. doi:10.1038/35004513. PMID 10724160.
- Kolluri, R; Tolias K F, Carpenter C L, Rosen F S, Kirchhausen T (May 1996). "Direct interaction of the Wiskott-Aldrich syndrome protein with the GTPase Cdc42". Proc. Natl. Acad. Sci. U.S.A. 93 (11): 5615–8. doi:10.1073/pnas.93.11.5615. PMC 39296. PMID 8643625.
- Symons, M; Derry J M, Karlak B, Jiang S, Lemahieu V, Mccormick F, Francke U, Abo A (March 1996). "Wiskott-Aldrich syndrome protein, a novel effector for the GTPase CDC42Hs, is implicated in actin polymerization". Cell 84 (5): 723–34. doi:10.1016/S0092-8674(00)81050-8. PMID 8625410.
- Ramesh, N; Antón I M, Hartwig J H, Geha R S (December 1997). "WIP, a protein associated with wiskott-aldrich syndrome protein, induces actin polymerization and redistribution in lymphoid cells". Proc. Natl. Acad. Sci. U.S.A. 94 (26): 14671–6. doi:10.1073/pnas.94.26.14671. PMC 25088. PMID 9405671.
- Antón, I M; Lu W, Mayer B J, Ramesh N, Geha R S (August 1998). "The Wiskott-Aldrich syndrome protein-interacting protein (WIP) binds to the adaptor protein Nck". J. Biol. Chem. 273 (33): 20992–5. doi:10.1074/jbc.273.33.20992. PMID 9694849.
- Banin, S; Gout I, Brickell P (August 1999). "Interaction between Wiskott-Aldrich Syndrome protein (WASP) and the Fyn protein-tyrosine kinase". Mol. Biol. Rep. 26 (3): 173–7. doi:10.1023/A:1006954206151. PMID 10532312.
- Cory, G O; MacCarthy-Morrogh L, Banin S, Gout I, Brickell P M, Levinsky R J, Kinnon C, Lovering R C (November 1996). "Evidence that the Wiskott-Aldrich syndrome protein may be involved in lymphoid cell signaling pathways". J. Immunol. 157 (9): 3791–5. PMID 8892607.
- Bunnell, S C; Henry P A, Kolluri R, Kirchhausen T, Rickles R J, Berg L J (October 1996). "Identification of Itk/Tsk Src homology 3 domain ligands". J. Biol. Chem. 271 (41): 25646–56. doi:10.1074/jbc.271.41.25646. PMID 8810341.
- Oda, A; Ochs H D, Lasky L A, Spencer S, Ozaki K, Fujihara M, Handa M, Ikebuchi K, Ikeda H (May 2001). "CrkL is an adapter for Wiskott-Aldrich syndrome protein and Syk". Blood 97 (9): 2633–9. doi:10.1182/blood.V97.9.2633. PMID 11313252.
- O'Sullivan E, Kinnon C, Brickell P (1999). "Wiskott-Aldrich syndrome protein, WASP". Int. J. Biochem. Cell Biol. 31 (3–4): 383–7. doi:10.1016/S1357-2725(98)00118-6. PMID 10224664.
- Snapper SB, Rosen FS (1999). "The Wiskott-Aldrich syndrome protein (WASP): roles in signaling and cytoskeletal organization". Annu. Rev. Immunol. 17: 905–29. doi:10.1146/annurev.immunol.17.1.905. PMID 10358777.
- Thrasher AJ, Kinnon C (2000). "The Wiskott-Aldrich syndrome". Clin. Exp. Immunol. 120 (1): 2–9. doi:10.1046/j.1365-2249.2000.01193.x. PMC 1905602. PMID 10759756.
- MBInfo - WASP and other Nucleation Promotion Factors
- GeneReviews/NIH/NCBI/UW entry on WAS-Related Disorders including Wiskott-Aldrich syndrome (WAS), X-linked thrombocytopenia (XLT), and X-linked congenital neutropenia (XLN)
- Online 'Mendelian Inheritance in Man' (OMIM) 300392
- Online 'Mendelian Inheritance in Man' (OMIM) 313900
- Wiskott-Aldrich Syndrome Protein at the US National Library of Medicine Medical Subject Headings (MeSH)