Figure 2.

Cell lines able to express FFA2 or FFA3 in an inducible manner. Short-chain fatty acids such as acetate and propionate are pleiotropic in action and many effects in cells are likely to be mediated via non-receptor mechanisms. To define FFA2- and FFA3-specific effects of such ligands, Stoddart et al. (2008b) established Flp-In TREx HEK293 cell lines able to express C-terminally eYFP tagged forms of human FFA2 (left hand panels) or FFA3 (right hand panels) in an antibiotic dependent fashion. In the absence of doxycycline (top panels) the receptors cannot be detected but after treatment with doxycycline (bottom panels) the characteristic pattern of cell surface location is observed. Actions of short-chain fatty acids produced without treatment of the cells with doxycycline were considered unspecific. eYFP, enhanced yellow fluorescent protein; FFA2/3, free fatty acid receptor 2/3.