title: NPM-ALK mediates phosphorylation of MSH2 at tyrosine 238, creating a functional deficiency in MSH2 and the loss of mismatch repair.
abstract: The vast majority of anaplastic lymphoma kinase-positive anaplastic large cell lymphoma (ALK+ALCL) tumors express the characteristic oncogenic fusion protein NPM-ALK, which mediates tumorigenesis by exerting its constitutive tyrosine kinase activity on various substrates. We recently identified MSH2, a protein central to DNA mismatch repair (MMR), as a novel binding partner and phosphorylation substrate of NPM-ALK. Here, using liquid chromatography-mass spectrometry, we report for the first time that MSH2 is phosphorylated by NPM-ALK at a specific residue, tyrosine 238. Using GP293 cells transfected with NPM-ALK, we confirmed that the MSH2(Y238F) mutant is not tyrosine phosphorylated. Furthermore, transfection of MSH2(Y238F) into these cells substantially decreased the tyrosine phosphorylation of endogenous MSH2. Importantly, gene transfection of MSH2(Y238F) abrogated the binding of NPM-ALK with endogenous MSH2, re-established the dimerization of MSH2:MSH6 and restored the sensitivity to DNA mismatch-inducing drugs, indicative of MMR return. Parallel findings were observed in two ALK+ALCL cell lines, Karpas 299 and SUP-M2. In addition, we found that enforced expression of MSH2(Y238F) into ALK+ALCL cells alone was sufficient to induce spontaneous apoptosis. In conclusion, our findings have identified NPM-ALK-induced phosphorylation of MSH2 at Y238 as a crucial event in suppressing MMR. Our studies have provided novel insights into the mechanism by which oncogenic tyrosine kinases disrupt MMR.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: K M
authors.initials: KM
authors.lastname: Bone
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Wu
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: J T
authors.initials: JT
authors.lastname: Bacani
authors.affiliation: Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: S E
authors.initials: SE
authors.lastname: Andrew
authors.affiliation: 1] Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada [2] Department of Oncology, University of Alberta, Edmonton, Alberta, Canada [3] DynaLIFEDX Medical Laboratories, Edmonton, Alberta, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Lai
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid; D053843:DNA Mismatch Repair / Q000502:physiology*; D006801:Humans; D047468:Immunoprecipitation; D017728:Lymphoma, Large-Cell, Anaplastic / Q000378:metabolism* / Q000473:pathology; D013058:Mass Spectrometry; D051718:MutS Homolog 2 Protein / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
chemical_list: D014443:Tyrosine; C107023:p80(NPM-ALK) protein; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; C497172:MSH2 protein, human; D051718:MutS Homolog 2 Protein