Untersuchung der Verbindung zwischen Splicing und der Lokalisierung des mRNA mittels Strukturbiologie
Zusammenfassung der Projektergebnisse
The discovery of several functional interactions where one or even both partners remain disordered has demonstrated that specific interactions do not necessarily require well-defined intermolecular interfaces. Here, using a combination of NMR spectroscopy and EMSAs, we have characterized a fuzzy protein–RNA complex formed by the intrinsically unfolded protein PYM and RNA. PYM is a cytosolic protein, which has been reported to bind the exon junction complex (EJC). In the process of oskar mRNA localization in Drosophila melanogaster, splicing of the first intron and deposition of the EJC are essential, while PYM is required to recycle the EJC components after localization has been accomplished. Here we demonstrated that the first 160 amino acids of PYM (PYM1–160) are intrinsically disordered. PYM1–160 binds RNA independently of its nucleotide sequence, forming a fuzzy protein–RNA complex which does not contain well-structured protein–RNA interfaces. The driving force for the interaction is charge complementarity, together with preservation of conformational entropy. Formation of this complex is incompatible with PYM’s binding to the EJC recycling factor. We propose that the role of RNA binding consists in down-regulating PYM activity by blocking the EJC interaction surface of PYM until localization has been accomplished. At the same time, the interaction of PYM with the RNA may contribute to ensure that PYM is localized together with the mRNA and the EJC. We suggest that the largely unstructured character of PYM may act to enable binding to a variety of diverse interaction partners, such as multiple RNA sequences and the EJC proteins Y14 and Mago. We propose that functional, fuzzy interactions between charged molecules may be much more common than previously thought. The less well-defined energy landscape underlying such interactions may allow the participants to fulfil multiple roles in different cellular pathways.
Projektbezogene Publikationen (Auswahl)
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PhD Thesis: Interaction of the spliced Oskar localization element of Oskar mRNA with the protein PYM Faculty of Natural Science of the Gottfried Wilhelm Leibniz University Hannover Veena Hegde, Master of Science (India)
Teresa Carlomagno
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The EJC disassembly factor PYM is an intrinsically disordered protein and forms a fuzzy complex with RNA. Frontiers in Molecular Biosciences, 10.
Verma, Deepshikha; Hegde, Veena; Kirkpatrick, John & Carlomagno, Teresa
