Laboratory of Experimental Endocrinology, School of Medicine, University of Crete, 71013, Greece.
Laboratory of Biochemistry, School of Medicine, University of Crete, 71013, Greece.
Biochim Biophys Acta Gen Subj. 2021 May;1865(5):129851. doi: 10.1016/j.bbagen.2021.129851. Epub 2021 Jan 19.
Nuclear translocation of large proteins is mediated through specific protein carriers, collectively named karyopherins (importins, exportins and adaptor proteins). Cargo proteins are recognized by importins through specific motifs, known as nuclear localization signals (NLS). However, only the NLS recognized by importin α and transportin (M9 NLS) have been identified so far METHODS: An unsupervised in silico approach was used, followed by experimental validation.
We identified the sequence EKRKI(E/R)(K/L/R/S/T) as an NLS signal for importin 7 recognition. This sequence was validated in the breast cancer cell line T47D, which expresses importin 7. Finally, we verified that importin 7-mediated nuclear protein transport is affected by cargo protein phosphorylation.
The NLS sequence for importin 7 was identified and we propose this approach as an identification method of novel specific NLS sequences for β-karyopherin family members.
Elucidating the complex relationships of the nuclear transporters and their cargo proteins may help in laying the foundation for the development of novel therapeutics, targeting specific importins, with an immediate translational impact.
大型蛋白质的核易位是通过特定的蛋白质载体介导的，这些载体统称为核输入蛋白（importins）、核输出蛋白（exportins）和衔接蛋白。货物蛋白通过特定的基序被 importins 识别，这些基序被称为核定位信号（NLS）。然而，迄今为止，仅鉴定出被 importin α 和 transportin（M9 NLS）识别的 NLS。
使用无监督的计算机方法，然后进行实验验证。
我们确定了 EKRKI(E/R)(K/L/R/S/T)序列为 importin 7 识别的 NLS 信号。该序列在表达 importin 7 的乳腺癌细胞系 T47D 中得到了验证。最后，我们验证了 importin 7 介导的核蛋白转运受货物蛋白磷酸化的影响。
鉴定了 importin 7 的 NLS 序列，我们提出了这种方法作为鉴定β-karyopherin 家族成员新的特定 NLS 序列的方法。
阐明核转运体及其货物蛋白之间的复杂关系，可能有助于为靶向特定 importins 的新型治疗药物的开发奠定基础，具有直接的转化意义。
