转铁蛋白受体及可溶性转铁蛋白受体

转铁蛋白受体（TfR）是由两个同源二聚体（180kDa）的亚基通过两条二硫键交联而成的一种II型跨膜糖蛋白，其功能是通过与转铁蛋白（If）的相互作用介导铁的吸收，其表达主要是根据细胞内铁水平进行转录后水平的调节。TfR还在细胞生长和增殖中发挥作用。最近的研究发现TfR在T细胞的激活中发挥了选择性的作用，但是具体的作用还不是完全清楚。可溶性转铁蛋白受体（sTiR）是细胞膜TfR经蛋白酶作用水解生成的分泌到血液中的组织片段，是细胞内Tffi被切断后的单体。是近年来TtR研究的一个新领域，一个新的铁代谢参数，且较稳定，不受炎症性疾病、感染、恶性肿瘤或溶血的影响，其含量与细胞的TIR量呈平行关系。本文就Tffi的结构、表达、功能以及sTiR的测定，参数界定及临床应用进行综述。

Transferrin receptor and soluble transferring receptor

The transferrin receptor （TfR） is a type - II transmembrane glycoprotein formed by subunits of 2 homodimers through cross - linking via 2 disulfide bonds. It mediates absorption of iron through interaction among the transferrins. Its expression is controlled by in- tracellular level of iron. Meanwhile, it can exert effects in cellular growth and proliferation. Recently, it has been found that TfR exerted effect of selection in activation of T cells. But the mechanism of which has not been clearly clarified. The soluble transferrin receptor （sTfR） is a kind of tissue fragments secreted into blood after the cell membrane TfR being hydrolyzed by p,＇otease. In recent years, sTfR has been widely studied to determine the effect of TfR because it is stable and not easily affected by inflammatory diseases, infections, ma- lignancies or hemolysis. In this paper, the structure, expression and function of TfR and measurement, index determination and clinical application of sTfR were reviewed.