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ＤＰＣ４／Ｓｍ ａｄ４ 是新近发现的一种对胰腺癌有抑制作用的基因。在大约６０％ 的胰腺癌细胞中这种基因发生缺失或失活。但后来发现其主要作用是参与转移生长因子－β（ｔｒａｎｓｆｏｒｍ ｉｎｇ ｇｒｏｗ ｔｈ ｆａｃｔｏｒ β，ＴＧＦ－β）超家族的信号传导。ＴＧＦ－β超家族的信号从细胞内传递到细胞核中是通过新发现的ＳＭＡＤｓ家族蛋白完成的。脊椎动物的ＳＭＡＤｓ家族蛋白包括８ 个成员，它们各自有不同的功能，可以分成３ 类：受体调节的ＳＭＡＤｓ，包括ＳＭＡＤ１～３，５和ＳＭＡＤ８；协同ＳＭＡＤ，包括ＳＭＡＤ４ 及拮抗ＳＭＡＤｓ（ＳＭＡＤ６ 和ＳＭＡＤ７）。受体调节ＳＭＡＤｓ传递信号必需与ＳＭＡＤ４ 形成异源复合物才能进到核中，进而与ＤＮＡ 结合，激活转录。因此ＳＭＡＤ４在ＳＭＡＤｓ传递信号时起中心作用。该文对ＳＭＡＤ４ 蛋白在细胞内信号传导中的最新研究进展进行了综述
DPC4/Sm ad4 is a recently discovered gene that has an inhibitory effect on pancreatic cancer. This gene is deleted or inactivated in about 60% of pancreatic cancer cells. However, it was later found that its main role is to participate in the signal transduction of the transforming growth factor beta (TGF-β) superfamily. Signaling of the TGF-β superfamily from the cell to the nucleus is accomplished by the newly discovered family of SMADs proteins. The vertebrate SMADs family of proteins includes 8 members, each of which has a different function and can be divided into 3 categories: receptor-regulated SMADs, including SMAD1-3,5, and SMAD8; synergistic SMADs, including SMAD4 and antagonistic SMADs (SMAD6 and SMAD7) ). Receptors that regulate SMADs signaling must form a heterologous complex with SMAD4 to enter the nucleus, which in turn binds to DNA and activates transcription. Therefore SMAD4 plays a central role in the transmission of signals by SMADs. This article reviews recent advances in the study of SMAD4 protein in intracellular signal transduction.