Functional expression of the Fc-fused extracellular domains of group II membrane proteins.

The complicated delivery mechanism of group II membrane proteins makes it difficult to decide the fusion pattern of their extracellular domains (ECDs) with Fc moiety. In this study, we compared the expression of ECDs of three group II membrane proteins including CLEC-2, Dectin-1, and LOX-1 by fusion of Fc moiety. We found that the pattern of ECD-Fc fusion order produced the functionally active recombinant proteins while the pattern of Fc-ECD fusion order led to the altered glycosylation which abolished the binding of these proteins with their ligands. Meanwhile, our results indicated that the secretion of mouse Fc (mFc)-fused ECD of CLEC-2 was more efficient than that of rabbit Fc (rFc)-fused protein, while rFc moiety was more sensitive for detection compared with mFc moiety. Altogether, we provide a favorable fusion pattern of Fc moiety with the ECDs of group II transmembrane proteins.