9opk

Crystal structure of IRAK4 with compound 1, an analog of KT-474 TBM

spinqualitylabelsall models 9opk, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9opk is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.05Å Ligands: A1CDD, EDO, GOL, SEP, TPO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease IRAK4_HUMAN Defects in IRAK4 are the cause of recurrent isolated invasive pneumococcal disease type 1 (IPD1) [MIM:610799. Recurrent invasive pneumococcal disease (IPD) is defined as two episodes of IPD occurring at least 1 month apart, whether caused by the same or different serotypes or strains. Recurrent IPD occurs in at least 2% of patients in most series, making IPD the most important known risk factor for subsequent IPD. Defects in IRAK4 are the cause of IRAK4 deficiency (IRAK4D) [MIM:607676. IRAK4 deficiency causes extracellular pyogenic bacterial and fungal infections in otherwise healthy children. Function IRAK4_HUMAN Serine/threonine-protein kinase that plays a critical role in initiating innate immune response against foreign pathogens. Involved in Toll-like receptor (TLR) and IL-1R signaling pathways. Is rapidly recruited by MYD88 to the receptor-signaling complex upon TLR activation to form the Myddosome together with IRAK2. Phosphorylates initially IRAK1, thus stimulating the kinase activity and intensive autophosphorylation of IRAK1. Phosphorylates E3 ubiquitin ligases Pellino proteins (PELI1, PELI2 and PELI3) to promote pellino-mediated polyubiquitination of IRAK1. Then, the ubiquitin-binding domain of IKBKG/NEMO binds to polyubiquitinated IRAK1 bringing together the IRAK1-MAP3K7/TAK1-TRAF6 complex and the NEMO-IKKA-IKKB complex. In turn, MAP3K7/TAK1 activates IKKs (CHUK/IKKA and IKBKB/IKKB) leading to NF-kappa-B nuclear translocation and activation. Alternatively, phosphorylates TIRAP to promote its ubiquitination and subsequent degradation. Phosphorylates NCF1 and regulates NADPH oxidase activation after LPS stimulation suggesting a similar mechanism during microbial infections. Publication Abstract from PubMed Targeted protein degradation has emerged as a promising drug modality, with potential applications across many immuno-inflammatory diseases. KT-474 is an orally bioavailable interleukin-1 receptor-associated kinase 4 (IRAK4) heterobifunctional degrader evaluated in clinical trials for atopic dermatitis and hidradenitis suppurativa. Here we present structural, biophysical, and computational characterization of an IRAK4:KT-474:CRBN/DDB1 complex. Cryo-EM structure of the complex reveals a unique and non-native protein-protein interaction (PPI) surface mediated by a network of polar and apolar contacts, including key hydrophobic engagements mediated by CRBN Phe150. This complex exhibits negative cooperativity, arising from an interplay between weakly favorable PPI and conformational flexibility of the degrader. Moreover, the structure provides insight into the selective degradation profile of KT-474. Our results offer important insights into the mechanism of action of KT-474 and highlight the value of cryo-EM structures in the optimization of protein degraders. Structural basis for selective and potent degradation of IRAK4 by KT-474.,Fei X, Ramanathan A, Daigle CA, Ford M, Campbell V, Zheng X, Sintchak M, Li H, Kamadurai H, Miller R, Kazmirski S, Huang X, Weiss MM, Mainolfi N, Zhu X Nat Commun. 2026 Jun 23. doi: 10.1038/s41467-026-74105-w. PMID:42336816 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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