Bimolecular Fluorescence Complementation (BiFC) for Studying Sarcomeric Protein Interactions in .

Protein-protein interactions in myofibrils are essential for their function and formation. Bimolecular Fluorescence Complementation (BiFC) is an effective method for studying protein interactions and localization. BiFC relies on the reconstitution of a monomeric fluorescent protein from two half-fragments when in proximity. Two proteins tagged with the different half-fragments emit a fluorescent signal when they are in physical contact, thus revealing a protein interaction and its spatial distribution. Because myofibrils are large networks of interconnected proteins, BIFC is an ideal method to study protein-protein interactions in myofibrils. Here we present a protocol for generating transgenic flies compatible with BiFC and a method for analyzing protein-protein interactions based on the fluorescent BiFC signal in myofibrils. Our protocol is applicable to the majority of proteins and with few modifications may be used to study any tissue.