Ryseck R P, Kovary K, Bravo R
Squibb Institute for Medical Research, Department of Molecular Biology, Princeton, New Jersey 08543-4000.
Oncogene. 1990 Jul;5(7):1091-3.
fos B encodes a nuclear protein with 70% homology to c-fos, whose expression is transiently induced during the G0/G1 transition. Immunoprecipitation studies demonstrated that FOS B protein forms a complex in vitro with c-JUN, JUN B, and JUN D. We have mutated some of the leucines of the 'leucine zipper' present in the FOS B protein and determined their effect in the interaction with JUN proteins and their binding to an AP-1 containing sequence. The exchange of either leucine 1, 3, or 5 of the leucine repeat of FOS B to a proline dramatically inhibits its association with JUN proteins. However, a more conserved substitution to isoleucine has only a 50% inhibition. These results demonstrate that any major alteration in the alpha-helical structure of the 'leucine zipper' completely inhibits the interaction of FOS B with any of the three JUN proteins.
Fos B编码一种与c-fos有70%同源性的核蛋白，其表达在G0/G1期转换过程中被短暂诱导。免疫沉淀研究表明，FOS B蛋白在体外与c-JUN、JUN B和JUN D形成复合物。我们对FOS B蛋白中“亮氨酸拉链”的一些亮氨酸进行了突变，并确定了它们在与JUN蛋白相互作用以及与含AP-1序列结合中的作用。将FOS B亮氨酸重复序列中的亮氨酸1、3或5替换为脯氨酸，会显著抑制其与JUN蛋白的结合。然而，将其替换为更保守的异亮氨酸，仅产生50%的抑制作用。这些结果表明，“亮氨酸拉链”的α螺旋结构发生任何重大改变都会完全抑制FOS B与三种JUN蛋白中任何一种的相互作用。
