通过蛋白质组学的方法鉴定小G蛋白Rif的相互作用蛋白及初步功能分析

Rif(Rho in filopodia)作为Rho小G蛋白家族的一员在调节细胞骨架形态方面有多种作用,可以同时介导压力纤维（stress fibers）和丝状伪足（filopodia）结构的形成.为了进一步研究Rif分子的功能, 通过蛋白质组学的方法在高表达内源性Rif蛋白的HeLa细胞中寻找其新的相互作用蛋白.通过分析,发现了Rif与输出蛋白5（exportin 5）等几个核质蛋白存在潜在的相互作用.实验证明,Rif与输出蛋白5的相互作用是核苷酸依赖性的，并且这种相互作用可以将细胞质中存在的输出蛋白5转运回细胞核内.这些发现揭示了小G蛋白Rif可能作为核质大分子运输载体的新功能.

A Search for the Binding Partners of Rif Small Rho GTPase by Proteomic Analyses

Rif, a member of small Rho GTPases, has multiple functions in regulating cytoskeleton morphology, mediating the formation of both stress fibers and filopodia. To elucidate the molecular functions of Rif in depth, I performed a proteomic screening for Rif protein partners in HeLa cells, which have a high level of expression of endogenous Rif. Analyses of Rif interactors revealed that Rif has the potential to interact with exportin 5 and several other members of karyopherins transport receptor family.I found that Rif binds exportin 5 in a nucleotide dependent manner, and this interaction directs the transport of exportin 5 from cytoplasm to nucleus. These findings reveal that Rif might have a novel function in mediating macromolecular trafficking between cytoplasmic and nuclear compartments.