内质网膜上的转运使者——易位子相关蛋白（TRAP）

内质网膜蛋白在参与信号序列的识别、新生肽链的修饰、转运通道的形成等生理过程中发挥重要作用.易位子相关蛋白（translocon-associated protein, TRAP）是广泛存在于高等真核生物中的一种膜蛋白，其作为信号序列的受体蛋白位于内质网膜上.该蛋白能选择性地识别信号序列，并与Sec61相互作用形成一个以Sec61为核心、TRAP侧向延伸的椭圆状转运通道，从而靶向新生肽链进入内质网腔.近来研究发现，TRAP与蛋白质构象病、神经退行性疾病、肿瘤转移等疾病的发病机制有关.本文将对TRAP各个亚基的最新研究及其功能作一综述.

The Current Progress in Translocon-associated Protein

Endoplasmic reticulum(ER)membrane proteins play a crucial role in physiological processes such as the recognition of signal sequence,the modification of nascent peptide and the form of translocation channel.Translocon-associated protein(TRAP),a widely existed membrane protein in higher eukaryotes,can be considered as a signal sequence receptor anchored at the ER membrane.The protein is able to recognize substrates in a signal sequence-specific manner,and interact with Sec61 through its transmembrane domain to form a translocation channel.Sec61 serves as a core,while TRAP forms a lateral extension to direct the nascent peptides to be inserted into the ER lumen.TRAP has a tripartite architecture with a prominent luminal domain that connects to Sec61 channel by two stalk-like characteristics.Recently,increasing number of studies demonstrated that TRAP may be related to the pathogenesis of protein conformation diseases,neurodegenerative disorders,ultraviolet-induced melanomagenesis and metastasis.This review primarily focuses on the latest study of the TRAP subunits and their functions.