Insect G Protein-Coupled Receptors and Signal Transduction

摘要

G protein-coupled receptors (GPCRs) are seven-transmembrane proteins (7-TM) that transduce extracellular signals into cellu-lar physiological responses through the activation of hetero-trimeric guanine nucleotide binding proteins (#alpha##beta##gamma# subunits). Their general properties are remarkably well conserved during evolution. Despite this general resemblance, a large variety of different signals are mediated via this category of receptors. Several GPCR-(sub)families have an ancient origin that is situ-ated before the divergence of Protostomian and Deuterostomian animals. Nevertheless, an enormous diversification has occurred since then. The availability of novel sequence information is growing very rapidly as a result of molecular cloning experi-ments and of metazoan genome (Caenorhabditis elegans, Droso-phila melanogaster, Homo sapiens) and EST (expressed sequence tags) sequencing projects. The Drosophila Genome Sequencing Project will certainly have an important impact on insect sig-nal transduction and receptor research. In parallel, convenient expression systems and functional assay procedures will be needed to investigate insect receptor properties and to moni-tor the effects of natural and artificialligands. The study of the evolutionary aspects of G protein-coupled receptors and of their signaling pathways will probably reveal insect-specific features. More insight into these features may result in novel methods and practical applications. Arch. Insect Biochem.