STRUCTURE OF THE FCRN RECEPTOR

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 新生儿Fc受体(FcRN)跨上皮细胞转运免疫球蛋白G(Ig G)，将Ig G结合到细胞顶端表面形成的酸性小泡(pH和lt；6.5)中，并在pH 7.4时将Ig G释放到血液中。这一过程的结构特征正在用电磁层析成像技术进行研究。特别是，我们将纳米金颗粒连接到恒定的免疫球蛋白片段(Fc)上，并在低pH值下将结合物应用于培养的单层MDCK细胞，并将它们作为新生大鼠的食物。在通过快速冷冻和冷冻替代制备相关细胞或组织之后，我们已经寻找了在细胞顶端及其附近的囊泡室内化金的证据。这些样品的初步断层图像显示，金有一些内化，但很难观察到。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The neonatal Fc receptor (FcRn) transports immunoglobulin G (IgG) across epithelia, binding IgG into acidic vesicles (pH< 6.5) that form on the apical surface of the cell and releasing IgG into the blood at pH7.4. Structural features of this process are being studied by EM tomography. In particular we have conjugated nanogold particles to the constant fragment (Fc) of IgG and have both administered the conjugates at low pH to cultured monolayers of MDCK cells and given them as food to neonatal rats. Following preparation of the relevant cells or tissues by rapid freezing and freeze substitution, we have looked for evidence of gold internalization in the vesicular compartments at and near the apical side of the cells. Preliminary tomograms of these samples show some internalization of gold, however it is difficult to visualize.