Chen Zhizhong, Qing Jilin, Qin Guifang, Hu Lihua
Department of Laboratory, The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning 530021, PR China.
Protein Expr Purif. 2012 Nov;86(1):1-6. doi: 10.1016/j.pep.2012.08.004. Epub 2012 Aug 23.
T cell immunoglobulin mucin-3 (TIM-3) is the first surface molecule to be found that specifically identifies Th1 cells in both mice and humans, and it negatively regulates Th1 responses. TIM-3 protein is a type I membrane protein. Overexpression of membrane proteins is a major problem to overcome in studies of membrane protein structure and function. In this study, a fusion between the gene encoding human TIM-3 and EGFP was successfully constructed and expressed in Escherichia coli. To our knowledge, this is the first time that human TIM-3 has been overexpressed in E. coli. We showed that the TIM-3-EGFP fusion protein mediates the recognition and binding of apoptotic cells. Furthermore, we demonstrated that the interactions of TIM-3-EGFP with apoptotic cells were blocked by TIM-3-Ig fusion proteins. Taken together, these results suggest that the human TIM-3 protein may act as a receptor for apoptotic cells.
T细胞免疫球蛋白黏蛋白-3（TIM-3）是在小鼠和人类中发现的首个可特异性识别Th1细胞的表面分子，它对Th1反应起负向调节作用。TIM-3蛋白是一种I型膜蛋白。膜蛋白的过表达是膜蛋白结构与功能研究中需要克服的一个主要问题。在本研究中，成功构建了编码人TIM-3的基因与EGFP的融合体，并在大肠杆菌中进行了表达。据我们所知，这是首次在大肠杆菌中实现人TIM-3的过表达。我们发现TIM-3-EGFP融合蛋白介导了对凋亡细胞的识别与结合。此外，我们还证明TIM-3-Ig融合蛋白可阻断TIM-3-EGFP与凋亡细胞的相互作用。综上所述，这些结果表明人TIM-3蛋白可能作为凋亡细胞的受体发挥作用。
