Hck kinase activity contributes to AP-1 transcriptional activation; Hck and PI3-K activated pathways converge upstream of AP-1.

Three times TRE-luciferase AP-1 reporter construct was transfected either alone (control), or together with kinase-dead Hck (267M/499F), or with constitutive active Hck (499F). Relative luciferase activity compared with control is shown. Coexpression of Hck267M/499F significantly reduces the constitutive AP-1 activity, whereas Hck499F increases AP-1 activation. Hck and PI3-K–activated pathways converge upstream of AP-1. Coexpression of membrane-targeted constitutive active PI3-K (p110) failed to rescue the Hck267M/499F-induced block in AP-1 activity (p110 + 267M/499F). The increased AP-1 activity induced by Hck 499F expression, however, was ablated by kinase-dead p110 (Δp110 + 499F). Thus, both Hck and PI3-K pathways converge to induce AP-1 transactivation. Mean and standard deviation of at least 3 independent experiments are shown. The error bars indicate the mean and standard deviation relative to vector control of 3 independent experiments.