title: Proteomic analysis reveals that MAEL, a component of nuage, interacts with stress granule proteins in cancer cells.
abstract: The Maelstrom (MAEL) gene is a cancer-testis (or cancer-germline) gene, which is predominantly expressed in germline cells under normal conditions, but is aberrantly expressed in a range of human cancer cells. In germline cells, MAEL is found predominantly in the nuage, where it plays an essential role in piRNA biogenesis and piRNA-mediated silencing of transposons. However, the role of MAEL in cancer has not been elucidated. We performed immunoprecipitation and Nano-LC-MS/MS analysis to investigate the interactome of MAEL, and identified 14 components of stress granules (SGs) as potential binding partners of MAEL in MDA-MB-231 human breast cancer and SW480 colorectal cancer cells. The interactions between MAEL and 8 of these SG components (PABPC1, YBX1, KHSRP, SYNCRIP, DDX39, ELAV1, EIF4A1 and EIF3F) were confirmed by anti-tag immunoprecipitation. Immunofluorescence analysis showed that MAEL co-localizes with the SG marker PABPC1 in SGs during oxidative stress. Nuages and SGs are the cytoplasmic RNA granules of germline cells and stressed somatic cells, respectively, and both serve as a platform for small RNA-mediated gene silencing. It is, therefore, suggested that MAEL may be involved in miRNA-mediated gene silencing in SGs, as it does in the nuage. This finding should be valuable toward understanding the function of MAEL in carcinogenesis.
authors.affiliation: Department of General Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China.
authors.forename: Liqin
authors.initials: L
authors.lastname: Yuan
authors.forename: Yuzhong
authors.initials: Y
authors.lastname: Xiao
authors.forename: Qiuzhi
authors.initials: Q
authors.lastname: Zhou
authors.forename: Dongmei
authors.initials: D
authors.lastname: Yuan
authors.forename: Baiping
authors.initials: B
authors.lastname: Wu
authors.forename: Gannong
authors.initials: G
authors.lastname: Chen
authors.forename: Jianlin
authors.initials: J
authors.lastname: Zhou
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005260:Female; D057809:HEK293 Cells; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D018384:Oxidative Stress; D039122:Poly(A)-Binding Protein I / Q000378:metabolism; D011485:Protein Binding; D040901:Proteomics; D034622:RNA Interference; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000096:biosynthesis; D014157:Transcription Factors
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; C552355:MAEL protein, human; D035683:MicroRNAs; D039122:Poly(A)-Binding Protein I; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D014157:Transcription Factors