1m7e
Crystal structure of the phosphotyrosine binding domain(PTB) of mouse Disabled 2(Dab2):implications for Reeling signaling
Structural highlights
FunctionDAB2_MOUSE Adapter protein that functions as clathrin-associated sorting protein (CLASP) required for clathrin-mediated endocytosis of selected cargo proteins. Can bind and assemble clathrin, and binds simultaneously to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and cargos containg non-phosphorylated NPXY internalization motifs, such as the LDL receptor, to recruit them to clathrin-coated pits. Can function in clathrin-mediated endocytosis independently of the AP-2 complex. Involved in endocytosis of integrin beta-1; this function seems to redundant with the AP-2 complex and seems to require DAB2 binding to endocytosis accessory EH domain-containing proteins such as EPS15, EPS15L1 and ITSN1. Involved in endocytosis of cystic fibrosis transmembrane conductance regulator/CFTR. Isoform p96 is involved in endocytosis of megalin/LRP2 lipoprotein receptor during embryonal development. Required for recycling of the TGF-beta receptor. Isoform p67 is not involved in LDL receptor endocytosis. Involved in CFTR trafficking to the late endosome. Involved in several receptor-mediated signaling pathways. Involved in TGF-beta receptor signaling and facilitates phosphorylation of the signal transducer SMAD2. Mediates TFG-beta-stimulated JNK activation. May inhibit the canoniocal Wnt/beta-catenin signaling pathway by stabilizing the beta-catenin destruction complex through a competing association with axin preventing its dephosphorylation through protein phosphatase 1 (PP1). Sequesters LRP6 towards clathrin-mediated endocytosis, leading to inhibition of Wnt/beta-catenin signaling. May activate non-canonical Wnt signaling. In cell surface growth factor/Ras signaling pathways proposed to inhibit ERK activation by interrupting the binding of GRB2 to SOS1 and to inhibit SRC by preventing its activating phosphorylation at 'Tyr-419'. Proposed to be involved in modulation of androgen receptor (AR) signaling mediated by SRC activation; seems to compete with AR for interaction with SRC. Plays a role in the CSF-1 signal transduction pathway. Plays a role in cellular differentiation. Involved in cell positioning and formation of visceral endoderm (VE) during embryogenesis and proposed to be required in the VE to respond to Nodal signaling coming from the epiblast. Required for the epithelial to mesenchymal transition, a process necessary for proper embryonic development. May be involved in myeloid cell differentiation and can induce macrophage adhesion and spreading. Isoform p67 may be involved in transcriptional regulation. May act as a tumor suppressor.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDisabled (Dab) 1 and 2 are mammalian homologues of Drosophila DAB. Dab1 is a key cytoplasmic mediator in Reelin signaling that controls cell positioning in the developing central nervous system, whereas Dab2 is an adapter protein that plays a role in endocytosis. DAB family proteins possess an amino-terminal DAB homology (DH) domain that is similar to the phosphotyrosine binding/phosphotyrosine interaction (PTB/PI) domain. We have solved the structures of the DH domains of Dab2 (Dab2-DH) and Dab1 (Dab1-DH) in three different ligand forms, ligand-free Dab2-DH, the binary complex of Dab2-DH with the Asn-Pro-X-Tyr (NPXY) peptide of amyloid precursor protein (APP), and the ternary complex of Dab1-DH with the APP peptide and inositol 1,4,5-trisphosphate (Ins-1,4,5-P3, the head group of phosphatidylinositol-4,5-diphosphate (PtdIns-4,5-P2)). The similarity of these structures suggests that the rigid Dab DH domain maintains two independent pockets for binding of the APP/lipoprotein receptors and phosphoinositides. Mutagenesis confirmed the structural determinants specific for the NPXY sequence and PtdIns-4,5-P2 binding. NMR spectroscopy confirmed that the DH domain binds to Ins-1,4,5-P3 independent of the NPXY peptides. These findings suggest that simultaneous interaction of the rigid DH domain with the NPXY sequence and PtdIns-4,5-P2 plays a role in the attachment of Dab proteins to the APP/lipoprotein receptors and phosphoinositide-rich membranes. Crystal structures of the Dab homology domains of mouse disabled 1 and 2.,Yun M, Keshvara L, Park CG, Zhang YM, Dickerson JB, Zheng J, Rock CO, Curran T, Park HW J Biol Chem. 2003 Sep 19;278(38):36572-81. Epub 2003 Jun 24. PMID:12826668[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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