Venus fluorescent protein-based bimolecular fluorescence complementation analysis of Ttyh1 and Rer1 interaction (green) in living COS-7 cells by fluorescence microscopy. Ttyh1 and Rer1 were tagged with N- and C-terminal fragments of the Venus fluorescent protein (VN and VC), respectively. DsRed2-ER was cotransfected to label the endoplasmic reticulum (ER, red). Scale bar: 25 μm. 