Functional Evaluation of PTEN Missense Mutations Using in Vitro Phosphoinositide Phosphatase Assay

摘要: The tumor suppressor gene PTEN is frequently mutated in diverse human cancers and autosomal dominant cancer predisposition disorders. Recent studies have shown that the lipid phosphatase activity of critical for its function negatively regulates phosphatidylinositol 3'-kinase-protein kinase B pathway. Although more than half mutations result protein truncation, a significant fraction are missense mutations. To examine whether tumor-derived germ-line-derived inactivate function, we constructed 42 distinct types expressed them Escherichia coli. purified (His)6-tagged proteins were tested their ability to dephosphorylate inositol 1,3,4,5-tetrakisphosphate 3,4,5-triphosphate. In addition, examined effect mutant PTENs on bind phospholipid membrane. results revealed majority [38 (90%)] eliminated or reduced all had no membrane binding PTEN. Our study indicated phosphoinositide important there may be other mechanisms inactivation not monitored by vitro assay assay.