Department of Chemistry and Drug Technology, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
Biophys Chem. 2012 Jan;160(1):46-53. doi: 10.1016/j.bpc.2011.09.003. Epub 2011 Sep 17.
The protein ERp57 (also known as PDIA3) is a widely distributed protein, mainly localized in the endoplasmic reticulum, where it acts as disulfide isomerase, oxidoreductase and chaperone, in concert with the lectins calreticulin (CRT) and calnexin. The ERp57/CRT complex has been detected on the cell surface and previous studies have suggested its involvement in programmed cell death. Although the ERp57-CRT complex has been characterized, little is known about its role in different cellular compartments as well as inhibitors of this interaction. We focused on the kinetic, extent and stability of the ERp57-CRT complex, using the surface plasmon resonance spectroscopy, investigating the possible role as inhibitor of the antibiotic vancomycin. Equilibrium thermodynamic data suggested that vancomycin may hinder the interaction between the two proteins and could interfere with the ERp57 conformational changes that stabilize the complex. Furthermore, by means of confocal microscopy, we evaluated the effect of the in vivo administration of vancomycin on the ERp57/CRT complex on the surface of HeLa cells. The model presented here could be used for the search of other specific inhibitors/interactors of ERp57, which can be extremely helpful to understand the biological pathways where the protein is involved and to modulate its activity.
蛋白质 ERp57（也称为 PDIA3）是一种广泛分布的蛋白质，主要定位于内质网中，在那里它作为二硫键异构酶、氧化还原酶和伴侣，与凝集素钙网蛋白（CRT）和钙联蛋白协同作用。已经在细胞表面检测到 ERp57/CRT 复合物，并且先前的研究表明其参与程序性细胞死亡。尽管已经对 ERp57-CRT 复合物进行了表征，但对于其在不同细胞区室中的作用以及该相互作用的抑制剂知之甚少。我们使用表面等离子体共振光谱法专注于 ERp57-CRT 复合物的动力学、程度和稳定性，研究了抗生素万古霉素作为抑制剂的可能作用。平衡热力学数据表明，万古霉素可能会阻碍两种蛋白质之间的相互作用，并可能干扰稳定复合物的 ERp57 构象变化。此外，通过共聚焦显微镜，我们评估了万古霉素在体内给药对 HeLa 细胞表面 ERp57/CRT 复合物的影响。这里提出的模型可用于寻找 ERp57 的其他特异性抑制剂/相互作用物，这对于理解该蛋白参与的生物学途径并调节其活性非常有帮助。
