Davis N, Ghosh S, Simmons D L, Tempst P, Liou H C, Baltimore D, Bose H R
Department of Microbiology, University of Texas, Austin 78712.
Science. 1991 Sep 13;253(5025):1268-71. doi: 10.1126/science.1891714.
The Rel-associated protein pp40 is functionally related to I kappa B, an inhibitor of the transcription factor NF-kappa B. Purified pp40 inhibits the DNA binding activity of the NF-kappa B protein complex (p50:p65 heterodimers), p50:c-Rel heteromers, and c-Rel homodimers. The sequence of the complementary DNA encoding pp40 revealed similarity to the gene encoding MAD-3, a protein with mammalian I kappa B-like activity. Protein sequencing of I kappa B purified from rabbit lung confirmed that MAD-3 encodes a protein similar to I kappa B. The sequence similarity between MAD-3 and pp40 includes a casein kinase II and consensus tyrosine phosphorylation site, as well as five repeats of a sequence found in the human erythrocyte protein ankyrin. These results suggest that rel-related transcription factors, which are capable of cytosolic to nuclear translocation, may be held in the cytosol by interaction with related cytoplasmic anchor molecules.
与Rel相关的蛋白pp40在功能上与IκB相关，IκB是转录因子NF-κB的一种抑制剂。纯化的pp40可抑制NF-κB蛋白复合物（p50:p65异二聚体）、p50:c-Rel异源二聚体及c-Rel同二聚体的DNA结合活性。编码pp40的互补DNA序列显示与编码MAD-3的基因相似，MAD-3是一种具有哺乳动物IκB样活性的蛋白。对从兔肺中纯化的IκB进行蛋白质测序证实，MAD-3编码一种与IκB相似的蛋白。MAD-3与pp40之间的序列相似性包括一个酪蛋白激酶II和共有酪氨酸磷酸化位点，以及在人红细胞膜收缩蛋白中发现的一段序列的五个重复。这些结果表明，能够从胞质转运至核内的Rel相关转录因子，可能通过与相关胞质锚定分子相互作用而滞留于胞质中。
