2ykt | pdb_00002ykt
Crystal structure of the I-BAR domain of IRSp53 (BAIAP2) in complex with an EHEC derived Tir peptide
Structural highlights
Function[BAIP2_HUMAN] Adapter protein that links membrane-bound small G-proteins to cytoplasmic effector proteins. Necessary for CDC42-mediated reorganization of the actin cytoskeleton and for RAC1-mediated membrane ruffling. Involved in the regulation of the actin cytoskeleton by WASF family members and the Arp2/3 complex. Plays a role in neurite growth. Acts syngeristically with ENAH to promote filipodia formation. Plays a role in the reorganization of the actin cytoskeleton in response to bacterial infection.[1] [2] [3] [4] [TIR_ECO5T] 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 (By similarity). Publication Abstract from PubMedActin assembly beneath enterohemorrhagic E. coli (EHEC) attached to its host cell is triggered by the intracellular interaction of its translocated effector proteins Tir and EspF(U) with human IRSp53 family proteins and N-WASP. Here, we report the structure of the N-terminal I-BAR domain of IRSp53 in complex with a Tir-derived peptide, in which the homodimeric I-BAR domain binds two Tir molecules aligned in parallel. This arrangement provides a protein scaffold linking the bacterium to the host cell's actin polymerization machinery. The structure uncovers a specific peptide-binding site on the I-BAR surface, conserved between IRSp53 and IRTKS. The Tir Asn-Pro-Tyr (NPY) motif, essential for pedestal formation, is specifically recognized by this binding site. The site was confirmed by mutagenesis and in vivo-binding assays. It is possible that IRSp53 utilizes the NPY-binding site for additional interactions with as yet unknown partners within the host cell. Structural basis for complex formation between human IRSp53 and the translocated intimin receptor Tir of enterohemorrhagic E. coli.,de Groot JC, Schluter K, Carius Y, Quedenau C, Vingadassalom D, Faix J, Weiss SM, Reichelt J, Standfuss-Gabisch C, Lesser CF, Leong JM, Heinz DW, Bussow K, Stradal TE Structure. 2011 Sep 7;19(9):1294-306. PMID:21893288[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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