2ci9
From Proteopedia
Nck1 SH2-domain in complex with a dodecaphosphopeptide from EPEC protein Tir
Structural highlights
Function[NCK1_HUMAN] Adapter protein which associates with tyrosine-phosphorylated growth factor receptors, such as KDR and PDGFRB, or their cellular substrates. Maintains low levels of EIF2S1 phosphorylation by promoting its dephosphorylation by PP1. Plays a role in the DNA damage response, not in the detection of the damage by ATM/ATR, but for efficient activation of downstream effectors, such as that of CHEK2. Plays a role in ELK1-dependent transcriptional activation in response to activated Ras signaling.[1] [2] [3] [TIR_ECO27] Multifunctional protein that is required for efficient pedestal formation in host epithelial cells during infection. The extracellular region acts as a receptor for bacterial intimin, allowing the bacterium to attach tightly to the host-cell surface. Simultaneously, the intracellular region initiates a signaling cascade in the host cell, which leads to actin polymerization and formation of actin pedestals at the sites of bacterial adhesion. In strain E2348/69, acts mainly via the host adaptor proteins NCK1 and NCK2. Once clustered and phosphorylated at Tyr-474, Tir binds to NCK proteins, which in turn bind and activate host WASL/N-WASP, leading to actin polymerization. Can also trigger an inefficient, NCK-independent pedestal formation. This pathway involves phosphorylation of Tyr-454 and probably a putative host adaptor. Acts also via direct binding to the host cytoskeletal protein alpha-actinin in a NCK- and phosphotyrosine-independent manner. This interaction may stabilize the pedestal, but is not essential for its formation.[4] [5] [6] [7] [8] [9] 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 PubMedNck proteins are essential Src homology (SH) 2 and SH3 domain-bearing adapters that modulate actin cytoskeleton dynamics by linking proline-rich effector molecules to tyrosine kinases or phosphorylated signaling intermediates. Two mammalian pathogens, enteropathogenic Escherichia coli and vaccinia virus, exploit Nck as part of their infection strategy. Conflicting data indicate potential differences in the recognition specificities of the SH2 domains of the isoproteins Nck1 (Nckalpha) and Nck2 (Nckbeta and Grb4). We have characterized the binding specificities of both SH2 domains and find them to be essentially indistinguishable. Crystal structures of both domains in complex with phosphopeptides derived from the enteropathogenic E. coli protein Tir concur in identifying highly conserved, specific recognition of the phosphopeptide. Differential peptide recognition can therefore not account for the preference of either Nck in particular signaling pathways. Binding studies using sequentially mutated, high affinity phosphopeptides establish the sequence variability tolerated in peptide recognition. Based on this binding motif, we identify potential new binding partners of Nck1 and Nck2 and confirm this experimentally for the Arf-GAP GIT1. The phosphotyrosine peptide binding specificity of Nck1 and Nck2 Src homology 2 domains.,Frese S, Schubert WD, Findeis AC, Marquardt T, Roske YS, Stradal TE, Heinz DW J Biol Chem. 2006 Jun 30;281(26):18236-45. Epub 2006 Apr 24. PMID:16636066[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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