Tachibana T, Hieda M, Sekimoto T, Yoneda Y
Department of Anatomy and Cell Biology, Osaka University Medical School, Japan.
FEBS Lett. 1996 Nov 18;397(2-3):177-82. doi: 10.1016/s0014-5793(96)01180-5.
p10/NTF2 is a cytosolic factor which is required for the translocation step in nuclear protein import in an in vitro assay with digitonin-permeabilized cells. To study the functional roles of p10/NTF2 on protein transport between the nucleus and cytoplasm in living cells, recombinant p10/NTF2 was micro-injected into cultured mammalian cells. Cytoplasmically injected p10/NTF2 strongly inhibited the nuclear import of co-injected NLS-containing substrates in a dose-dependent manner but had no effect on the diffusive import of small non-nuclear proteins. Moreover, when injected into the cell nucleus, p10/NTF2 inhibited the nuclear export of NES-containing substrates. The results suggest that the nuclear import factor p10/NTF2 may also be involved in the nuclear export of proteins and that the protein transport efficiency between the nucleus and cytoplasm may be regulated by the intracellular level of p10/NTF2.
p10/NTF2是一种胞质因子，在用洋地黄皂苷通透化细胞进行的体外测定中，它是核蛋白输入转运步骤所必需的。为了研究p10/NTF2在活细胞中核与细胞质之间蛋白质运输的功能作用，将重组p10/NTF2显微注射到培养的哺乳动物细胞中。细胞质注射的p10/NTF2以剂量依赖的方式强烈抑制共注射的含核定位信号（NLS）底物的核输入，但对小的非核蛋白的扩散性输入没有影响。此外，当注射到细胞核中时，p10/NTF2抑制含核输出信号（NES）底物的核输出。结果表明，核输入因子p10/NTF2可能也参与蛋白质的核输出，并且核与细胞质之间的蛋白质运输效率可能受细胞内p10/NTF2水平的调节。
