title: Proteomic Analysis Reveals a Novel Mutator S (MutS) Partner Involved in Mismatch Repair Pathway.
abstract: The mismatch repair (MMR) family is a highly conserved group of proteins that function in correcting base-base and insertion-deletion mismatches generated during DNA replication. Disruption of this process results in characteristic microsatellite instability (MSI), repair defects, and susceptibility to cancer. However, a significant fraction of MSI-positive cancers express MMR genes at normal levels and do not carry detectable mutation in known MMR genes, suggesting that additional factors and/or mechanisms may exist to explain these MSI phenotypes in patients. To systematically investigate the MMR pathway, we conducted a proteomic analysis and identified MMR-associated protein complexes using tandem-affinity purification coupled with mass spectrometry (TAP-MS) method. The mass spectrometry data have been deposited to the ProteomeXchange with identifier PXD003014 and DOI 10.6019/PXD003014. We identified 230 high-confidence candidate interaction proteins (HCIPs). We subsequently focused on MSH2, an essential component of the MMR pathway and uncovered a novel MSH2-binding partner, WDHD1. We further demonstrated that WDHD1 forms a stable complex with MSH2 and MSH3 or MSH6,i.e.the MutS complexes. The specific MSH2/WDHD1 interaction is mediated by the second lever domain of MSH2 and Ala(1123)site of WDHD1. Moreover, we showed that, just like MSH2-deficient cells, depletion of WDHD1 also led to 6-thioguanine (6-TG) resistance, indicating that WDHD1 likely contributes to the MMR pathway. Taken together, our study uncovers new components involved in the MMR pathway, which provides candidate genes that may be responsible for the development of MSI-positive cancers.
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030.
authors.forename: Mykim
authors.initials: M
authors.lastname: Tran
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030.
authors.forename: Mengfan
authors.initials: M
authors.lastname: Tang
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Wang
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030 zgong@mdanderson.org jchen8@mdanderson.org.
authors.forename: Zihua
authors.identifier: http://orcid.org/0000-0002-8008-0615
authors.initials: Z
authors.lastname: Gong
authors.affiliation: From the ‡Department of Experimental Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, 6565 MD Anderson Boulevard, Houston, TX 77030 zgong@mdanderson.org jchen8@mdanderson.org.
authors.forename: Junjie
authors.initials: J
authors.lastname: Chen
mesh_terms: D001665:Binding Sites; D053843:DNA Mismatch Repair; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051718:MutS Homolog 2 Protein / Q000737:chemistry / Q000378:metabolism; D000074081:MutS Homolog 3 Protein; D009369:Neoplasms / Q000378:metabolism*; D011485:Protein Binding; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C078444:MSH3 protein, human; D000074081:MutS Homolog 3 Protein; C544202:WDHD1 protein, human; C497172:MSH2 protein, human; D051718:MutS Homolog 2 Protein