信号识别颗粒(SRP)在膜蛋白定位中的作用

Role of signal recognition particle in membrane protein targeting

摘要:

依赖信号识别颗粒(signal recognition particle，SRP)的共翻译转运是所有生命体中的一个保守途径，它将新生肽链的翻译与转运耦联在一起。超过30%的新合成的多肽链被SRP转运到正确位置。最近的研究表明，大肠杆菌中SRP抑制子可以规避SRP的需求。当SRP缺失时，翻译控制在介导膜蛋白定位方面起着关键作用。本综述总结了SRP底物如何在存在或缺失SRP的情况下转运到适当的位置以及翻译速率降低如何补偿SRP的缺失。我们还讨论了不同蛋白质对SRP的依赖程度。这一回顾将为进一步研究SRP功能及膜蛋白定位提供新思路。

Abstract:

Signal recognition particle (SRP)-dependent co-translational protein targeting is a conserved pathway across all kingdoms of life. It couples the translation and translocation of nascent peptides. Over 30% of newly synthesized peptides are delivered to the correct localization by SRP. Recent studies have demonstrated that SRP suppressors can circumvent the SRP requirement in Escherichia coli. The translational control plays a critical role in mediating membrane protein targeting when SRP is absent. This review summarizes how the substrates of SRP translocate to the proper localization with or without SRP, and how the decreased translation rate compensates for the loss of SRP. Furthermore, we discuss the dependence of different proteins on SRP. This review will provide new ideas for further studies about the function of SRP and membrane protein targeting.