Deciphering Ethylene Signaling via Protein-Protein Interaction in Tomato Fruit

Plant ethylene receptors (ETRs) form complicated protein complexes at endoplasmic reticulum membranes. The receptors function as dimers, and they gather to form higher-order protein complexes, together with other proteins that modulate ethylene signaling. Co-immunoprecipitation is a useful biochemical tool for determining the composition of protein complexes. Here, we introduce a basic co-immunoprecipitation scheme that includes preparation of microsomal fraction, immunoprecipitation, and mass spectrometry (MS) analysis for protein identification. Although the ETR protein complex in tomato fruit is addressed here, the protocol may be adapted to other fruit species with some modifications.