细胞因子和生长因子信号转导途径中信号蛋白分子的核转运机制

信号蛋白分子的入核及出核转运是细胞因子和生长因子信号转导途径中的重要环节.核定位序列（NLS）是信号蛋白分子上与入核转运相关的氨基酸序列.核孔复合物（NPC）、核转运蛋白importin和能量供应体Ran/TC4在入核转运过程中也发挥了重要作用.另外，很多细胞因子和生长因子或其受体上所含有的NLS序列也具有核定位功能，并可能通过“伴侣机制”参与其他信号蛋白分子的入核转运.

Mechanism on Nuclear Transport of Signaling Molecules in The Signal Transduction Pathways of Cytokines and Growth Factors

Nuclear import and export of signaling molecules is an important step in the signal transduction pathways of cytokines and growth factors. Nuclear localization sequence(NLS) is the specific amino acid sequence on the signaling proteins to be sufficient for their nuclear translocation. In addition, nuclear pore complex(NPC),nuclear transport protein-importin and the energy-providing GTPase-Ran/TC4 are also involved in the nuclear import of the signaling molecules. NLSs are also widely located on the cytokines, growth factors or their receptors, and these ligands or receptors may act as chaperon molecules to assist nuclear translocation of other intracelluler signaling proteins through the action of NLS.