PTEN Redundancy: Overexpressing lpten, a Homolog of Dictyostelium discoideum ptenA, the Ortholog of Human PTEN, Rescues All Behavioral Defects of the Mutant ptenA−

Mutations in the tumor suppressor gene PTEN are associated with a significant proportion of human cancers. Because the human genome also contains several homologs of PTEN , we considered the hypothesis that if a homolog, functionally redundant with PTEN, can be overexpressed, it may rescue the defects of a PTEN mutant. We have performed an initial test of this hypothesis in the model system Dictyostelium discoideum , which contains an ortholog of human PTEN , ptenA . Deletion of ptenA results in defects in motility, chemotaxis, aggregation and multicellular morphogenesis. D. discoideum also contains lpten , a newly discovered homolog of ptenA. Overexpressing lpten completely rescues all developmental and behavioral defects of the D. discoideum mutant ptenA − . This hypothesis must now be tested in human cells.