Dimethylsulphoxide as a tool to increase functional expression of heterologously produced GPCRs in mammalian cells.

High-level overexpression of G protein-coupled receptors GPCRs in mammalian cells remains a difficult task inspite of newly developed virus based expression systems. Here, we show that the functional expression level of the recombinant bradykinin receptor (B(2)R) in mammalian cells can be increased up to sixfold just by the addition of dimethylsulphoxide in the culture medium. Total expression level, cellular localization and binding affinity of the recombinant receptor for its endogenous ligand remains unaltered. The strategy presented here, with recombinant B(2)R as a case example, is applicable to other GPCRs and provides a generic tool to improve the functional expression level of recombinant GPCRs in mammalian cells.