Design of fusion proteins for bimolecular fluorescence complementation (BiFC).

Bimolecular fluorescence complementation (BiFC) analysis enables direct visualization of protein interactions in living cells. It is based on the facilitated association of two nonfluorescent fragments of a fluorescent protein fused to putative interaction partners. The intrinsic fluorescence of the active complex enables detection of protein interactions with high sensitivity, fine spatial resolution, and minimal perturbation of the cells. As discussed in more detail here, BiFC analysis requires careful consideration of the design and expression of the fusion proteins for the results to be interpretable.