ATP-Binding Pocket-Targeted Suppression of Src and Syk by Luteolin Contributes to Its Anti-Inflammatory Action

Figure 4

The mode of inhibition of Src kinase activity by luteolin. ((a), (b), and (e)) HEK293 cells (5 × 10⁶ cells/mL) were transfected with Src-WT, Src-KD, Src-CA, Src-dSH2, Src-dSH3, Src-D404A, Src-K295A, or Src-M341G in the presence or absence of luteolin. After preparing whole lysates, the levels of total or phosphorylated Src, HA, and β-actin were determined by immunoblotting. (c) Kinase assays were performed using immunoprecipitated Src as the enzyme, and immunoprecipitated p85 as the substrate, in the presence of ATP and luteolin. Src activity was determined by measuring the levels of phospho-p85 by immunoblotting analysis. (d) The putative binding site of luteolin in the ATP-binding pocket of Src. (f) The inhibitory effects of PP2 or piceatannol (Picea) on the production of NO or PGE₂ were examined using the Griess assay and EIA. All data are expressed as the mean ± SD of experiments that were performed with six or three samples. and compared to the control group.

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