Bearz A, Tell G, Colombatti A, Formisano S, Pucillo C
Department of Biomedical Sciences and Technologies, University of Udine, Italy.
Biochem Biophys Res Commun. 1998 Feb 24;243(3):732-7. doi: 10.1006/bbrc.1997.8017.
NF-kappa B was identified as one of the transcription factors leading to antigen-independent stimulation through activation of integrin receptors. This effect was dependent upon stimulation of alpha 4 beta 1 and alpha 5 beta 1 integrins, the major fibronectin-binding integrins of Jurkat T cells, since either RGD or CS-1 peptides at 10(-4) M could prevent NF-kappa B activation. At variance with fibroblasts and smooth muscle cells, in which only p50 and p65 components of the NF-kappa B complex are induced, adhesion of T cells to fibronectin resulted in a strong upregulation of p50 and c-Rel and in a partial increase in p65 activity. The upregulation of NF-kappa B activity was abrogated by calphostin C, an inhibitor of protein kinase C. Cell adhesion determined a strong reduction in the cytoplasmic levels of the NF-kappa B inhibitor I kappa B alpha, reduction that was prevented after treatment with calphostin C, suggesting that PKC-dependent I kappa B alpha phosphorylation might be involved in the upregulation of NF-kappa B.
核因子-κB被确定为通过整合素受体激活导致抗原非依赖性刺激的转录因子之一。这种效应依赖于对α4β1和α5β1整合素的刺激，这是Jurkat T细胞主要的纤连蛋白结合整合素，因为10⁻⁴M的RGD或CS-1肽均可阻止核因子-κB的激活。与成纤维细胞和平滑肌细胞不同，在成纤维细胞和平滑肌细胞中仅诱导核因子-κB复合物的p50和p65成分，T细胞与纤连蛋白的黏附导致p50和c-Rel的强烈上调以及p65活性的部分增加。蛋白激酶C抑制剂钙泊三醇C可消除核因子-κB活性的上调。细胞黏附导致核因子-κB抑制剂IκBα的细胞质水平显著降低，在用钙泊三醇C处理后这种降低被阻止，这表明蛋白激酶C依赖性的IκBα磷酸化可能参与了核因子-κB的上调。
