Studying interactions between chloroplast proteins in intact plant cells using bimolecular fluorescence complementation and Förster resonance energy transfer.

Protein-protein interactions play crucial roles in the execution of many cellular functions, including those in plastids. Identifying and characterising protein-protein interactions can yield valuable information regarding the function of a protein and can also contribute towards understanding protein-protein interaction networks in plastids, thereby contributing to a better understanding of cellular processes. Here, we describe the planning and experimental procedures required to perform both bimolecular fluorescence complementation and Förster resonance energy transfer assays to detect protein-protein interactions. Arabidopsis is well-suited for microscopy and its small size facilitates live cell imaging, enabling observation of protein-protein interactions in living chloroplasts. The methods described in this chapter can be used to analyse protein-protein interactions of two known proteins and to dissect interacting protein domains.