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Background. The incidence of gout has been rapidly increasing in recent years with the changing of diet. At present, modern medications used in the clinical treatment of gout showed several side effects, such as gastrointestinal damage and the increased risk of cardiovascular disease. The traditional Chinese prescription Simiao Powder (SMP) has a long history in the treatment of acute gouty arthritis (AGA) and has a good curative effect. However, the mechanism and target of its therapeutic effects are still not completely understood. Methods. Potential active compounds (PACs) and targets of SMP were found in the TCMSP database, and the disease target genes related to AGA were obtained by searching CTD, DisGeNET, DrugBank, GeneCards, TTD, OMIM, and PharmGKB disease databases with "acute gouty arthritis" and "Arthritis, Gouty" as keywords, respectively. The network of "Traditional Chinese medicine (TCM)-PACs-potential targets of acute gouty arthritis" was constructed with the Cytoscape 3.7.2 software, and the target genes of acute gouty arthritis were intersected with genes regulated by active compounds of SMP. The resultant common gene targets were input into Cytoscape 3.7.2 software, and the BisoGenet plug-in was used to construct a PPI network. The GO functional enrichment analysis and KEGG pathway enrichment analysis of the intersecting target proteins were performed using R software and corresponding program packages. The molecular docking verification was carried out between the potentially active compounds of SMP and the core target at the same time. Results. 40 active components and 203 targets were identified, of which 95 targets were common targets for the drugs and diseases. GO function enrichment analysis revealed that SMP regulated several biological processes, such as response to lipopolysaccharide and oxidative stress, RNA polymerase II transcription regulator complex, protein kinase complex, and other cellular and molecular processes, including DNA-binding transcription factor binding. Results of KEGG pathway analysis showed that SMP was associated with AGA-related pathways such as interleukin-17 (IL-17), tumor necrosis factor (TNF), p53, and hypoxia-inducible factor 1 (HIF-1) signaling pathways. The results of molecular docking showed that active compounds in SMP exhibited strong binding to five core protein receptors (TP53, FN1, ESR1, CDK2, and HSPA5). Conclusions. Active components of SMP, such as quercetin, kaempferol, wogonin, baicalein, beta-sitosterol, and rutaecarpine, showed therapeutic effects on AGA. These compounds were strongly associated with core target proteins (such as TP53, FN1, ESR1, CDK2, and HSPA5). This study reveals that IL-17, TNF, p53, and HIF-1 signaling pathways mediate the therapeutic effects of SMP on AGA. These findings expand our understanding of the mechanism of SMP in the treatment of AGA. [ABSTRACT FROM AUTHOR]

In contrast to the active conformations of protein kinases, which are essentially the same for all kinases, inactive kinase conformations are structurally diverse. Some inactive conformations are, however, observed repeatedly in different kinases, perhaps reflecting an important role in catalysis. In this review, we analyze one of these recurring conformations, first identified in CDK and Src kinases, which turned out to be central to understanding of how kinase domain of the EGF receptor is activated. This mechanism, which involves the stabilization of the active conformation of an α helix, has features in common with mechanisms operative in several other kinases. [Copyright &y& Elsevier]

Abstract: Epidermal growth factor receptor (EGFR) and its family members, ErbB2, ErbB3 and ErbB4, are receptor tyrosine kinases which send signals into the cell to regulate many critical processes including development, tissue homeostasis, and tumorigenesis. Central to the signaling of these receptors is their intracellular kinase domain, which is activated by ligand-induced dimerization of the receptor and phosphorylates several tyrosine residues in the C-terminal tail. The phosphorylated tail then recruits other signaling molecules and relays the signal to downstream pathways. A model of the autoinhibition, activation and feedback inhibition mechanisms for the ErbB kinase domain has emerged from a number of recent structural studies. Meanwhile, recent clinical studies have revealed the relationship between specific ErbB kinase mutations and the responsiveness to kinase inhibitor drugs. We will review these regulation mechanisms of the ErbB kinase domain, and discuss the binding specificity of kinase inhibitors and the effects of kinase domain mutations found in cancer patients from a structural perspective. [Copyright &y& Elsevier]

Signaling through plexin, the major cell surface receptor for semaphorin, plays critical roles in regulating processes such as neuronal axon guidance, angiogenesis and immune response. Plexin is normally kept inactive in the absence of semaphorin. Upon binding of semaphorin to the extracellular region, plexin is activated and transduces signal to the inside of the cell through its cytoplasmic region. The GTPase Activating Protein (GAP) domain in the plexin cytoplasmic region mediates the major intracellular signaling pathway. The substrate specificity and regulation mechanisms of the GAP domain have only been revealed recently. Many intracellular proteins serve as either upstream regulators or downstream transducers by directly interacting with plexin. The mechanisms of action for some of these proteins also start to emerge from recent studies. We review here these advances in the mechanistic understanding of plexin intracellular signaling from a structural perspective. [ABSTRACT FROM AUTHOR]

Summary: The mutation and overexpression of the epidermal growth factor receptor (EGFR) are associated with the development of a variety of cancers, making this prototypical dimerization-activated receptor tyrosine kinase a prominent target of cancer drugs. Using long-timescale molecular dynamics simulations, we find that the N lobe dimerization interface of the wild-type EGFR kinase domain is intrinsically disordered and that it becomes ordered only upon dimerization. Our simulations suggest, moreover, that some cancer-linked mutations distal to the dimerization interface, particularly the widespread L834R mutation (also referred to as L858R), facilitate EGFR dimerization by suppressing this local disorder. Corroborating these findings, our biophysical experiments and kinase enzymatic assays indicate that the L834R mutation causes abnormally high activity primarily by promoting EGFR dimerization rather than by allowing activation without dimerization. We also find that phosphorylation of EGFR kinase domain at Tyr845 may suppress the intrinsic disorder, suggesting a molecular mechanism for autonomous EGFR signaling. [ABSTRACT FROM AUTHOR]