title: Protein interactions of phosphatase and tensin homologue (PTEN) and its cancer-associated G20E mutant compared by using stable isotope labeling by amino acids in cell culture-based parallel affinity purification.
abstract: The tumor suppressor PTEN (phosphatase and tensin homologue) negatively regulates the PI3K pathway through its lipid phosphatase activity and is one of the most commonly lost tumor suppressors in human cancers. Though the tumor suppressive function involves the lipid phosphatase-dependent and -independent activities of PTEN, the mechanism leading to the phosphatase-independent function of PTEN is understood poorly. Some PTEN mutants have lipid phosphatase activity but fail to suppress cell growth. Here, we use a cancer-associated mutant, G20E, to gain insight into the phosphatase-independent function of PTEN by investigating protein-protein interactions using MS-based stable isotope labeling by amino acids in cell culture (SILAC). A strategy named parallel affinity purification (PAP) and SILAC has been developed to prioritize interactors and to compare the interactions between wild-type and G20E PTEN. Clustering of the prioritized interactors acquired by the PAP-SILAC approach shows three distinct clusters: 1) wild-type-specific interactors, 2) interactors unique to the G20E mutant, and 3) proteins common to wild-type and mutant. These interactors are involved mainly in cell migration and apoptosis pathways. We further demonstrate that the wild-type-specific interactor, NUDTL16L1, is required for the regulatory function of wild-type PTEN in cell migration. These findings contribute to a better understanding of the mechanisms of the phosphatase-dependent and -independent functions of PTEN.
authors: Cancer Science Institute of Singapore, National University of Singapore, 28 Medical Drive, 117456 Singapore.
authors: Jayantha
authors: J
authors: Gunaratne
authors: Mei Xian
authors: MX
authors: Goh
authors: Hannah Lee Foon
authors: HL
authors: Swa
authors: Fen Yee
authors: FY
authors: Lee
authors: Emma
authors: E
authors: Sanford
authors: Loke Meng
authors: LM
authors: Wong
authors: Kelly A
authors: KA
authors: Hogue
authors: Walter P
authors: WP
authors: Blackstock
authors: Koichi
authors: K
authors: Okumura
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D045744:Cell Line, Tumor; D006801:Humans; D007553:Isotope Labeling / Q000379:methods; D020125:Mutation, Missense; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D009363:Neoplasm Proteins; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human