Biochemie/Molekularbiologie
Zusammenfassung der Projektergebnisse
Funded by the Heisenberg-Fellowship my research was focused on the post-transcriptional control of gene expression. Projects comprised the regulation of mRNA translation by RNA-binding proteins (RBPs) in different processes including cellular differentiation (control of protein synthesis in enucleated erythroid cells), tumor development (VEGF expression under hypoxic conditions), viral RNA expression (regulation of HCV RNA translation) and inflammation (innate immune response of macrophages). The influence of post-translational modifications on the structure, function and localization of regulatory RBPs in specific RNA-protein complexes (RNPs) was a key aspect of my work. Arginine methylation is a common post-translational modification in higher eukaryotes, but information about its biological role in post-transcriptional control of gene expression is insufficient so far. Post-translational modifications of hnRNP K that modulate its function in RNA-protein complexes attracted special attention. Earlier we identified hnRNP K as specific regulator of mRNA translation in erythroid cells. Interestingly, hnRNP K was found to interact with tyrosine kinase c-Src and to activate the enzyme. Phosphorylation of Y458 by c-Src modulates the RNA binding activity of hnRNP K and controls its function in translation regulation. Mass spectrometry analysis and Edman sequencing of purified hnRNP K identified five quantitatively asymmetrically dimethylated arginine residues (R256, 258, 268, 296, 299). We analyzed the methylating enzyme and characterized protein arginine methyltransferase 1 (PRMT1) as the specific enzyme acting on hnRNP K in vitro and in vivo. Arginine methylation did not influence hnRNP K functions as RBP and regulator of mRNA translation or its cellular localization. However, hnRNP K methylation diminished the interaction with c-Src, resulting in inhibition of c-Src activation and hnRNP K phosphorylation. These findings indicate that hnRNP K arginine methylation specifically regulates its interaction with signaling proteins.
Projektbezogene Publikationen (Auswahl)
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(2005): Structure of the hepatitis C virus IRES bound to the human 80S ribosome: remodeling of the HCV IRES. Structure, Vol. 13. 2005, Issue 11, pp. 1695–1706.
Boehringer B, Thermann R, Ostareck-Lederer A, Lewis JD, Stark H
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(2006) The DICE-binding activity of KH domain 3 of hnRNP K is affected by c-Src mediated tyrosine phosphorylation. Journal of Molecular Biology, Vol. 361. 2006, Issue 3, pp. 470–481.
Messias, A., Harnisch, C., Ostareck-Lederer, A., Sattler, M. and Ostareck, D.H.
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(2006): Asymmetric arginine dimethylation of heterogeneous nuclear ribonucleoprotein K by protein-arginine methyltransferase 1 inhibits its interaction with c-Src. The Journal of Biological Chemistry, Vol. 281. 2006, pp. 11115-11125.
Ostareck-Lederer A, Ostareck DH, Rücknagel KP, Schierhorn A, Moritz B, Hüttelmaier S, Flach N, Handoko L, Wahle E
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(2007) Nuclear factors are involved in Hepatitis C Virus RNA replication. RNA, Vol. 13.2007, pp. 1675-1692.
Isken O, Baroth M, Grassmann C, Weinlich S, Ostareck DH, Ostareck-Lederer A, Behrens SE
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(2007): Deciphering the crosstalk between hnRNP K and c-Src: The c-Src activation domain in hnRNP K is distinct from the site of interaction. Molecular and Cellular Biology, vol. 27. 2007, no. 5, pp. 1758-1770.
Adolph D, Flach N, Müller K, Ostareck DH, Ostareck-Lederer, A
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(2008) mRNA silencing in human erythroid cell maturation: hnRNP K controls the synthesis of its regulator c-Src. The Journal of Biological Chemistry, Vol. 283.2008, pp 18461-18472.
Naarmann IS, Harnisch C, Flach,N, Kremmer E, Kühn H, Ostareck DH, Ostareck-Lederer A
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(2008): mRNA silencing in human erythroid cell maturation: hnRNP K controls the synthesis of its regulator c-Src. J. Biol. Chem. 283, 18461-18472
Naarmann IS, Harnisch C, Flach N, Kremmer E, Kühn H, Ostareck DH, Ostareck-Lederer A
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(2008): Promiscuous modification of the nuclear poly(A) binding protein by multiple protein-arginine methyltransferases does not affect the aggregation behavior. The Journal of Biological Chemistry, Vol. 283. 2008 , pp. 20408-20420.
Fronz K, Otto S, Kölbel K, Kühn U, Friedrich H, Schierhorn A, Beck-Sickinger AG, Ostareck- Lederer A, Wahle E
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2008 1st International Meeting, GRK 1026 “Conformational Transitions in Macromolecular Interactions”, Halle (Saale), Germany
Christiane Harnisch
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(2009) Proteomic analysis of increased Parkin expression
Proteomic analysis of increased Parkin expression and its interactants provides evidence for a role in modulation of mitochondrial function. PROTEOMICS, Vol. 9.2009, Issue 18, pp. 4284–4297.
Davison EJ, Pennington K, Hung CC, Peng J, Rafiq, Ostareck-Lederer A, Ostareck DH, Ardley HC, Banks RE, Robinson PA
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(2009): IGF2BP1 enhances HCV IRES-mediated translation initiation via the 3’UTR. RNA, Vol. 15. 2009, pp. 1528-1542.
Weinlich S, Hüttelmaier S, Schierhorn A, Behrens SE, Ostareck-Lederer A, Ostareck DH
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(2010) Arginine methylation in subunits of mammalian pre-mRNA cleavage factor I. RNA, Vol. 16. 2010, pp. 1646-1659.
Martin G, Ostareck-Lederer A, Chari A, Neuenkirchen N., Dettwiler S, Blank D, Rüegsegger U, Fischer U, Keller W
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(2010) DDX6 recruits translational silenced human reticulocyte 15-lipoxygenase mRNA to RNP granules. RNA. Vol. 16.2010, pp. 2189-2204.
Naarmann IS, Harnisch C, Müller-Newen G, Urlaub H, Ostareck-Lederer A, Ostareck D.H.
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(2010): Plakophilin 1 stimulates translation by promoting eIF4A1 activity. J. Cell Biol. 188(4) 463-471
Wolf A, Krause-Gruszczynska M, Birkenmeier O, Ostareck-Lederer A, Hüttelmaier S, Hatzfeld M
