Mass Spectrometry Analysis of Human CB2 Cannabinoid Receptor and Its Associated Proteins

Studying the assemblies and dynamics of the complex formed by cannabinoid receptors and their associated proteins is important for understanding the molecular basis for the functions of these receptors. In the absence of the crystal structures of these macromolecular complexes, mass spectrometry is a sensitive technique that can be used to study cannabinoid receptors and their associated proteins. In this chapter, three aspects of the work are presented: (1) mass spectrometry analysis of the primary sequence of the human CB2 cannabinoid receptor after affinity chromatography purification of the receptor proteins, (2) functional proteomic analysis of CB2-associated proteins coimmunoprecipitated with CB2, and (3) chemical cross-linking and mass spectrometry analysis of CB2-G protein complex. The mass spectrometry approaches, in combination with mutagenesis and molecular modeling techniques, have been successfully used for studying the CB2-G protein complex. Similar approaches can also be applied for studying other G protein-coupled receptors in general.