Identification of a homologue for annexin VII (synexin) in Dictyostelium discoideum

Immunological and biochemical data have been used to show that the slime mold Dictyostelium discoideum expresses a Ca2+/phospholipid-binding protein related to vertebrate annexins. The Dictyostelium protein (apparent molecular mass 46 kDa) is recognized by an antibody directed against an annexin consensus peptide and exhibits the properties characteristic for annexins, i.e. it interacts in a Ca2(+)-dependent manner with negatively charged phospholipids. Limited proteolysis converts the 46-kDa protein into a 32-kDa derivative which retains the Ca2+/phospholipid-binding properties of the 46-kDa polypeptide. Partial protein sequence data identify the Dictyostelium protein as the typical annexin and indicate that the 46-kDa protein is an annexin VII (synexin) homologue. The identification of an annexin in a simple eucaryote should lead to the introduction of genetic approaches to analyze the physiological role of the annexins.