NUCLEOCYTOPLASMIC TRANSPORT

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 蛋白质和核酸的核质转运对于正常细胞功能至关重要。它通过核孔复合物的方式发生，并由一个小的GTdR，Ran控制。最近提出的两个模型（Smith等人，Science（2002），Gorlich等人，EMBO J（2002））预测了Ran核质转运对Ran鸟嘌呤交换因子RCC 1（一种在细胞核中将Ran转化为GTP结合形式的酶）活性的非常不同的敏感性。模型的比较分析表明，它们在结构上是相似的，但假设有些不同的酶活性，特别是，20倍不同的孔渗透性的RAN进入细胞核。活细胞中的荧光相关光谱（FCS）被用于直接测量反应速率和该途径中组分的移动的分数，以评估这些模型中哪一个最适合实验情况。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Nucleocytoplasmic transport of proteins and nucleic acids is crucial for normal cell functioning. It occurs by way of nuclear pore complexes and is controlled by a small GTPase, Ran. Two recently proposed models (Smith et al., Science (2002), Gorlich et al., EMBO J (2002)) predict very different sensitivity of the Ran nucleocytoplasmic transport to the activity of the Ran guanine exchange factor, RCC1, an enzyme converting Ran to the GTP-bound form in the nucleus. A comparative analysis of the models shows that they are structurally similar but assume somewhat different enzyme activities and, particularly, 20-fold different pore permeability for the Ran entry into the nucleus. Fluorescence correlation spectroscopy (FCS) in live cells is being used to directly measure reaction rates and mobile fractions of components in this pathway to assess which of these models best fit the experimental situation.