title: Human G3BP1 interacts with beta-F1-ATPase mRNA and inhibits its translation.
abstract: The post-transcriptional regulation of nuclear mRNAs that encode core components of mitochondria has relevant implications in cell physiology. The mRNA that encodes the catalytic subunit of the mitochondrial H(+)-ATP synthase subunit beta (ATP5B, beta-F1-ATPase) is localized in a large ribonucleoprotein (RNP) complex (beta-F1-RNP), which is subjected to stringent translational control during development and the cell cycle, and in carcinogenesis. Because downregulation of beta-F1-ATPase is a conserved feature of most prevalent human carcinomas, we have investigated the molecular composition of the human beta-F1-RNP. By means of an improved affinity-chromatography procedure and protein sequencing we have identified nine RNA-binding proteins (RNABPs) of the beta-F1-RNP. Immunoprecipitation assays of Ras-GAP SH3 binding protein 1 (G3BP1) and fluorescent in-situ hybridization of mRNA indicate a direct interaction of the endogenous G3BP1 with mRNA of beta-F1-ATPase (beta-F1 mRNA). RNA-bridged trimolecular fluorescence complementation (TriFC) assays confirm the interaction of G3BP1 with the 3'-UTR of beta-F1 mRNA in cytoplasmic RNA-granules. Confocal and high-resolution immunoelectron-microscopy experiments suggest that the beta-F1-RNP is sorted to the periphery of mitochondria. Molecular and functional studies indicate that the interaction of G3BP1 with beta-F1 mRNA inhibits its translation at the initiation level, supporting a role for G3BP1 in the glycolytic switch that occurs in cancer.
authors.affiliation: Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CBMSO), CSIC-UAM, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), ISCIII, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Alvaro D
authors.initials: AD
authors.lastname: Ortega
authors.forename: Imke M
authors.initials: IM
authors.lastname: Willers
authors.forename: Sandra
authors.initials: S
authors.lastname: Sala
authors.forename: José M
authors.initials: JM
authors.lastname: Cuezva
mesh_terms: D020413:3' Untranslated Regions; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D014176:Protein Biosynthesis; D020365:RNA Helicases; D000067776:RNA Recognition Motif Proteins; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D020413:3' Untranslated Regions; C506526:ATP5F1B protein, human; D002352:Carrier Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000067776:RNA Recognition Motif Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D025261:Mitochondrial Proton-Translocating ATPases; D004265:DNA Helicases; C116070:G3BP1 protein, human; D020365:RNA Helicases