Heterotrimeric Guanine Nucleotide-binding Proteins in Eukaryotic Parasites

Parasites, in order to survive, must be able to recognize and respond to signals in their environment. This is particularly so when parasite development is associated with moving from one environment to another as it is likely that a rapid process of adaptation that requires changes in gene expression will have to be initiated. In general, interaction with host signals takes place at the parasite surface, with the resulting need for information to be trasmitted to the interior. Many such signalling events in mammalian cells are regulated by a family of molecules referred to as guanine nucleotide-binding proteins (G proteins). The structure and function of these molecules, and evidence obtained to date of the roles that they may play in parasitic organisms, are discussed here by Bill and Maggie Harnett.