Nucleocytoplasmic shuttling of Smad proteins

活跃 Smad 建筑群的原子累积为转变生长因素尾的 transduction 是关键的(从进原子核的 transmembrane 受体的 TGF- 尾) 总科信号。在缺席和一个 TGF- 尾 - 总科信号的存在， Smads 的 nucleocytoplasmic 分布不是静态的，现在是清楚的，但是相反 Smads 是连续地，在原子核之间的 shuttling 和在两个的细胞质调节。这篇文章为 Smads 的连续 nucleocytoplasmic shuttling 介绍证据。它然后考察被建议了调停的不同机制 Smad 原子进出口，并且讨论在缺席的 Smad 不变的分布和一个 TGF- 尾 - 总科信号的存在怎么被建立。最后，为由 TGF- 尾总科成员发信号的连续 nucleocytoplasmic shuttling 的生物关联被讨论。

Nuclear accumulation of active Smad complexes is crucial for transduction of transforming growth factor β （TGF-β）- superfamily signals from transmembrane receptors into the nucleus. It is now clear that the nucleocytoplasmic distributions of Smads, in both the absence and the presence of a TGF-β-superfamily signal, are not static, but instead the Smads are continuously shuttling between the nucleus and the cytoplasm in both conditions. This article presents the evidence for continuous nucleocytoplasmic shuttling of Smads. It then reviews different mechanisms that have been proposed to mediate Smad nuclear import and export, and discusses how the Smad steady-state distributions in the absence and the presence of a TGF-β-superfamily signal are established. Finally, the biological relevance of continuous nucleocytoplasmic shuttling for signaling by TGF-β superfamily members is discussed.