G-protein Coupled Receptors (GPCRs) are the most diverse family of proteins in animals, regulating a vast array of biological functions including vision, gestation, neural activity, development, etc. Each GPCR spans the cell membrane and binds to a specific compound (ligand) on the exterior of the cell. The GPCR transduces this binding event into a cellular signal, which alters cell metabolism. GPCRs have been studied intensively in humans and most pharmaceutical compounds target these receptors. However, GPCRs in invertebrates are relatively poorly characterised. Invertebrate GPCRs will become increasingly important for invertebrate research as GPCR characterisation will increase our understanding of invertebrate molecular biology and in producing targets for compounds developed for studying and controlling invertebrates. Recent advances in molecular biology have seen a new field of research emerge whereby GPCRs are being adapted as biosensors. Here we express GPCRs and G proteins using baculovirus and show that a functional signalling complex can be reconstituted, in a cell-free format.