Expression of cargo receptor ERGIC-53 with defferernt sugar-binding specificities and the effect on carbohydrate structures attached on secretory and membrane proteins.

点击翻译按钮获取中文摘要

In secretory pathway newly synthesized secretory and membrane proteins undergo folding and glycosylation during the transport from the ER, through the Golgi. Transport along this pathway sorting of proteins are occurred by cargo receptors. ERGIC-53 is one of the cargo receptors with a leguminous lectin domain on its lumenal side and ER-retrieve signal peptide on its cytoplasmic tail. We constructed the cDNA coding ERGIC-53 substituted of its lectin domain into galactose-binding Bauhinia purpurea lectin (BPA) or sialic acid-binding Maackia amurensis lectin (MAH). Signal peptide on its carboxy terminus was also substituted into those of other trans Golgi localized proteins, TGN38, CI-MPR and furin. Chimeric cargo receptors were expressed in MDCK cells and the effect on the secretory pathway of the cells were analyzed, respectively. Based on the data of western blotting and flow cytometric analyses, chimeric ERGIC-53 with BPA at its lectin domain and TGN38 at cytoplasmic tail transported proteins rich in galactose to the surface of the cells and rich in galactose.