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NPM-ALK mediates phosphorylation of MSH2 at tyrosine 238, creating a functional deficiency in MSH2 and the loss of mismatch repair. Blood Cancer J 2015 May 15;5(5):e311

Date

05/16/2015

Pubmed ID

25978431

Pubmed Central ID

PMC4476014

DOI

10.1038/bcj.2015.35

Scopus ID

2-s2.0-84989896192 (requires institutional sign-in at Scopus site)   9 Citations

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.

Author List

Bone KM, Wang P, Wu F, Wu C, Li L, Bacani JT, Andrew SE, Lai R

Author

Kathleen M. Bone PhD Associate Professor in the Pathology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Blotting, Western
Cell Line, Tumor
Chromatography, Liquid
DNA Mismatch Repair
Humans
Immunoprecipitation
Lymphoma, Large-Cell, Anaplastic
Mass Spectrometry
MutS Homolog 2 Protein
Mutagenesis, Site-Directed
Phosphorylation
Protein-Tyrosine Kinases
Receptor Protein-Tyrosine Kinases
Transfection
Tyrosine