3d9u
From Proteopedia
The BIR3 domain of cIAP1 in complex with the N terminal peptide from SMAC/DIABLO (AVPIAQ).
Structural highlights
FunctionBIRC2_HUMAN Multi-functional protein which regulates not only caspases and apoptosis, but also modulates inflammatory signaling and immunity, mitogenic kinase signaling, and cell proliferation, as well as cell invasion and metastasis. Acts as an E3 ubiquitin-protein ligase regulating NF-kappa-B signaling and regulates both canonical and non-canonical NF-kappa-B signaling by acting in opposite directions: acts as a positive regulator of the canonical pathway and suppresses constitutive activation of non-canonical NF-kappa-B signaling. The target proteins for its E3 ubiquitin-protein ligase activity include: RIPK1, RIPK2, RIPK3, RIPK4, CASP3, CASP7, CASP8, TRAF2, DIABLO/SMAC, MAP3K14/NIK, MAP3K5/ASK1, IKBKG/NEMO and MXD1/MAD1. Can also function as an E3 ubiquitin-protein ligase of the NEDD8 conjugation pathway, targeting effector caspases for neddylation and inactivation. Acts as an important regulator of innate immune signaling via regulation of Toll-like receptors (TLRs), Nodlike receptors (NLRs) and RIG-I like receptors (RLRs), collectively referred to as pattern recognition receptors (PRRs). 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. Can stimulate the transcriptional activity of E2F1. Plays a role in the modulation of the cell cycle.[1] [2] [3] [4] [5] 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 protein (IAP) family of molecules inhibit apoptosis through the suppression of caspase activity. It is known that the XIAP protein regulates both caspase-3 and caspase-9 through direct protein-protein interactions. Specifically, the BIR3 domain of XIAP binds to caspase-9 via a ;hotspot' interaction in which the N-terminal residues of caspase-9 bind in a shallow groove on the surface of XIAP. This interaction is regulated via SMAC, the N-terminus of which binds in the same groove, thus displacing caspase-9. The mechanism of suppression of apoptosis by cIAP1 is less clear. The structure of the BIR3 domain of cIAP1 (cIAP1-BIR3) in complex with N-terminal peptides from both SMAC and caspase-9 has been determined. The binding constants of these peptides to cIAP1-BIR3 have also been determined using the surface plasmon resonance technique. The structures show that the peptides interact with cIAP1 in the same way that they interact with XIAP: both peptides bind in a similar shallow groove in the BIR3 surface, anchored at the N-terminus by a charge-stabilized hydrogen bond. The binding data show that the SMAC and caspase-9 peptides bind with comparable affinities (85 and 48 nM, respectively). The structure of the BIR3 domain of cIAP1 in complex with the N-terminal peptides of SMAC and caspase-9.,Kulathila R, Vash B, Sage D, Cornell-Kennon S, Wright K, Koehn J, Stams T, Clark K, Price A Acta Crystallogr D Biol Crystallogr. 2009 Jan;65(Pt 1):58-66. Epub 2008, Dec 18. PMID:19153467[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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