title: SERBP1 Is a Component of the Liver Receptor Homologue-1 Transcriptional Complex.
abstract: Liver receptor homologue-1 (LRH1) is an orphan nuclear receptor that has been shown to play a role in the transcriptional regulation of pathways involved in cancer. Elucidating the components of the LRH1 transcriptional complex to better understand endogenous regulation of the receptor as well as its role in cancer remains a high priority. A sub-cellular enrichment strategy coupled with proteomic approaches was employed to identify putative LRH1 co-regulators. Nuclear fractionation protocol was essential for detection of LRH1 peptides by mass spectrometry (MS), with most peptides being observed in the insoluble fraction (receptor bound to DNA). SERBP1 and ILF3 were identified as LRH1 interacting partners by both Western blot and MS/MS analysis. Receptor knockdown by siRNA showed an increase in SERBP1 expression, while ILF3 expression was unchanged. In contrast, receptor overexpression decreased only SERBP1 mRNA levels. Consistent with these data, in a promoter:reporter assay, binding of LRH1 to the promoter region of SERBP1 resulted in a decrease in the expression level of the reporter gene, subsequently inhibiting transcription. Given the receptor's role in cancer progression, the study here elucidates additional transcriptional machinery involved in LRH1 signaling and potentially provides new targets for therapeutics development.
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Yelenis
authors.initials: Y
authors.lastname: Mari
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Graham M
authors.initials: GM
authors.lastname: West
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Catherina
authors.initials: C
authors.lastname: Scharager-Tapia
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Pascal
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Ruben D
authors.initials: RD
authors.lastname: Garcia-Ordonez
authors.affiliation: Department of Molecular Therapeutics, ‡Mass Spectrometry & Proteomics Core, and §Informatics Core, The Scripps Research Institute , Jupiter, Florida 33458, United States.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Griffin
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D005591:Chemical Fractionation; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D050779:Nuclear Factor 90 Proteins / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011484:Protein-Arginine N-Methyltransferases / Q000235:genetics / Q000378:metabolism; D059748:Proteolysis; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: C429643:ILF3 protein, human; C082631:NR5A2 protein, human; D050779:Nuclear Factor 90 Proteins; C486497:PPARGC1A protein, human; D010455:Peptides; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D012097:Repressor Proteins; C428129:SERBP1 protein, human; D014157:Transcription Factors; C099988:PRMT1 protein, human; D011484:Protein-Arginine N-Methyltransferases
keywords: SERPINE1 mRNA binding protein-1 (SERBP1); interleukin enhancer binding factor-3 (ILF3); liver receptor homologue-1 (LRH1; NR5A2); nuclear receptor; peroxisome proliferator-activated receptor γ co-activator-1α (PGC1α); protein arginine methyltransferase 1 (PRMT1)