1g3f
From Proteopedia
NMR STRUCTURE OF A 9 RESIDUE PEPTIDE FROM SMAC/DIABLO COMPLEXED TO THE BIR3 DOMAIN OF XIAP
Structural highlights
DiseaseXIAP_HUMAN Defects in XIAP are the cause of lymphoproliferative syndrome X-linked type 2 (XLP2) [MIM:300635. XLP is a rare immunodeficiency characterized by extreme susceptibility to infection with Epstein-Barr virus (EBV). Symptoms include severe or fatal mononucleosis, acquired hypogammaglobulinemia, pancytopenia and malignant lymphoma.[1] FunctionXIAP_HUMAN Multi-functional protein which regulates not only caspases and apoptosis, but also modulates inflammatory signaling and immunity, copper homeostasis, mitogenic kinase signaling, cell proliferation, as well as cell invasion and metastasis. Acts as a direct caspase inhibitor. Directly bind to the active site pocket of CASP3 and CASP7 and obstructs substrate entry. Inactivates CASP9 by keeping it in a monomeric, inactive state. Acts as an E3 ubiquitin-protein ligase regulating NF-kappa-B signaling and the target proteins for its E3 ubiquitin-protein ligase activity include: RIPK1, CASP3, CASP7, CASP8, CASP9, MAP3K2/MEKK2, DIABLO/SMAC, AIFM1, CCS and BIRC5/survivin. Ubiquitinion of CCS leads to enhancement of its chaperone activity toward its physiologic target, SOD1, rather than proteasomal degradation. Ubiquitinion of MAP3K2/MEKK2 and AIFM1 does not lead to proteasomal degradation. Plays a role in copper homeostasis by ubiquitinationg COMMD1 and promoting its proteasomal degradation. Can also function as E3 ubiquitin-protein ligase of the NEDD8 conjugation pathway, targeting effector caspases for neddylation and inactivation. Regulates the BMP signaling pathway and the SMAD and MAP3K7/TAK1 dependent pathways leading to NF-kappa-B and JNK activation. Acts as an important regulator of innate immune signaling via regulation of Nodlike receptors (NLRs). Protects cells from spontaneous formation of the ripoptosome, a large multi-protein complex that has the capability to kill cancer cells in a caspase-dependent and caspase-independent manner. Suppresses ripoptosome formation by ubiquitinating RIPK1 and CASP8. Acts as a positive regulator of Wnt signaling and ubiquitinates TLE1, TLE2, TLE3, TLE4 and AES. Ubiquitination of TLE3 results in inhibition of its interaction with TCF7L2/TCF4 thereby allowing efficient recruitment and binding of the transcriptional coactivator beta-catenin to TCF7L2/TCF4 that is required to initiate a Wnt-specific transcriptional program.[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 PubMedThe inhibitor-of-apoptosis proteins (IAPs) regulate programmed cell death by inhibiting members of the caspase family of enzymes. Recently, a mammalian protein called Smac (also named DIABLO) was identified that binds to the IAPs and promotes caspase activation. Although undefined in the X-ray structure, the amino-terminal residues of Smac are critical for its function. To understand the structural basis for molecular recognition between Smac and the IAPs, we determined the solution structure of the BIR3 domain of X-linked IAP (XIAP) complexed with a functionally active nine-residue peptide derived from the N terminus of Smac. The peptide binds across the third beta-strand of the BIR3 domain in an extended conformation with only the first four residues contacting the protein. The complex is stabilized by four intermolecular hydrogen bonds, an electrostatic interaction involving the N terminus of the peptide, and several hydrophobic interactions. This structural information, along with the binding data from BIR3 and Smac peptide mutants reported here, should aid in the design of small molecules that may be used for the treatment of cancers that overexpress IAPs. Structural basis for binding of Smac/DIABLO to the XIAP BIR3 domain.,Liu Z, Sun C, Olejniczak ET, Meadows RP, Betz SF, Oost T, Herrmann J, Wu JC, Fesik SW Nature. 2000 Dec 21-28;408(6815):1004-8. PMID:11140637[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Homo sapiens | Large Structures | Betz SF | Fesik SW | Herrmann J | Liu Z | Meadows RP | Olejniczak ET | Oost T | Sun C | Wu JC
