Kerr L D, Inoue J, Davis N, Link E, Baeuerle P A, Bose H R, Verma I M
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92186-5800.
Genes Dev. 1991 Aug;5(8):1464-76. doi: 10.1101/gad.5.8.1464.
The product of proto-oncogene Rel associates with a number of cellular proteins. We have studied the effect of one of them, a phosphoprotein of 40 kD (pp40), on the DNA-binding activity of the Rel protein. We demonstrate that purified pp40 not only inhibits the binding of Rel, but also NF-kappa B (p50-p65) heterocomplex to DNA. Additionally, I kappa B beta, but not I kappa B alpha, also prevented the binding of Rel to the kappa B site. I kappa B beta and pp40 are related proteins because (1) they share a number of common tryptic peptides, (2) their inhibitory effect on DNA binding can be abolished by preincubation with pp40-specific antiserum, and (3) labeled I kappa B beta can be immunoprecipitated with pp40 antibodies. pp40 is part of the Rel complex present in the cytoplasm and nuclear extracts of WEHI-231 cells. The activity of pp40 to inhibit the DNA binding of Rel and NF-kappa B is modulated by phosphorylation.
原癌基因Rel的产物与许多细胞蛋白相关。我们研究了其中一种蛋白，即40kD的磷蛋白（pp40）对Rel蛋白DNA结合活性的影响。我们证明，纯化的pp40不仅抑制Rel的结合，还抑制NF-κB（p50-p65）异源复合物与DNA的结合。此外，IκBβ而非IκBα也能阻止Rel与κB位点的结合。IκBβ和pp40是相关蛋白，原因如下：（1）它们有许多共同的胰蛋白酶肽段；（2）它们对DNA结合的抑制作用可通过与pp40特异性抗血清预孵育而消除；（3）标记的IκBβ可用pp40抗体进行免疫沉淀。pp40是存在于WEHI-231细胞胞质和核提取物中的Rel复合物的一部分。pp40抑制Rel和NF-κB DNA结合的活性受磷酸化调节。
