Expression of Folate Receptor Protein in CHO Cell Line

One of cell surface receptor proteins, human folate receptor (hFR) involves in the uptake of folates through cell membrane into cytoplasm, and is anchored to the plasma membrane by a fatty acid linkage, which has been identified in some cells as a glycosylphosphatidylinositol (GPI)-tailed protein with a molecular mass of about 40 kDa. The hFR is released by phosphatidylinositol phospholipase C (PI-PLC) because it contains fatty acids and inositol on the GPI tail. Caveolin decorates the cytoplasmic surface of caveolae and has been proposed to have a structural role in maintaining caveolae. It is unknown whether caveolin is involved in targeting, and is necessary for the function of GPI-tailed proteins. To compare the ability of folic acid binding, internalization and expression of hFR, and the effect of caveolin at the both apical and basolateral side of cell surfaces in Chinese hamster ovary (CHO) clone cells overexpressed the hFR and/or caveolin. Our present results suggest a possibility that the overexpression of caveolin does not be involved in expression of hFR, but plays a role as a factor in PI-PLC releasing kinetics, and for a regulation of formation, processing and function of hFR in CHO clone cells overexpressed cavcolin.