Publications by authors named "Andreea Scacioc"

9 Publications

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The RESOLUTE consortium: unlocking SLC transporters for drug discovery.

Authors:
Giulio Superti-Furga Daniel Lackner Tabea Wiedmer Alvaro Ingles-Prieto Barbara Barbosa Enrico Girardi Ulrich Goldmann Bettina Gürtl Kristaps Klavins Christoph Klimek Sabrina Lindinger Eva Liñeiro-Retes André C Müller Svenja Onstein Gregor Redinger Daniela Reil Vitaly Sedlyarov Gernot Wolf Matthew Crawford Robert Everley David Hepworth Shenping Liu Stephen Noell Mary Piotrowski Robert Stanton Hui Zhang Salvatore Corallino Andrea Faedo Maria Insidioso Giovanna Maresca Loredana Redaelli Francesca Sassone Lia Scarabottolo Michela Stucchi Paola Tarroni Sara Tremolada Helena Batoulis Andreas Becker Eckhard Bender Yung-Ning Chang Alexander Ehrmann Anke Müller-Fahrnow Vera Pütter Diana Zindel Bradford Hamilton Martin Lenter Diana Santacruz Coralie Viollet Charles Whitehurst Kai Johnsson Philipp Leippe Birgit Baumgarten Lena Chang Yvonne Ibig Martin Pfeifer Jürgen Reinhardt Julian Schönbett Paul Selzer Klaus Seuwen Charles Bettembourg Bruno Biton Jörg Czech Hélène de Foucauld Michel Didier Thomas Licher Vincent Mikol Antje Pommereau Frédéric Puech Veeranagouda Yaligara Aled Edwards Brandon J Bongers Laura H Heitman Ad P IJzerman Huub J Sijben Gerard J P van Westen Justine Grixti Douglas B Kell Farah Mughal Neil Swainston Marina Wright-Muelas Tina Bohstedt Nicola Burgess-Brown Liz Carpenter Katharina Dürr Jesper Hansen Andreea Scacioc Giulia Banci Claire Colas Daniela Digles Gerhard Ecker Barbara Füzi Viktoria Gamsjäger Melanie Grandits Riccardo Martini Florentina Troger Patrick Altermatt Cédric Doucerain Franz Dürrenberger Vania Manolova Anna-Lena Steck Hanna Sundström Maria Wilhelm Claire M Steppan

Nat Rev Drug Discov 2020 07;19(7):429-430

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http://dx.doi.org/10.1038/d41573-020-00056-6DOI Listing
July 2020

Structure based biophysical characterization of the PROPPIN Atg18 shows Atg18 oligomerization upon membrane binding.

Sci Rep 2017 10 25;7(1):14008. Epub 2017 Oct 25.

Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.

PROPPINs (β-propellers that bind polyphosphoinositides) are PtdIns3P and PtdIns(3,5)P binding autophagy related proteins. They contain two phosphatidylinositolphosphate (PIP) binding sites and a conserved FRRG motif is essential for PIP binding. Here we present the 2.0 Å resolution crystal structure of the PROPPIN Atg18 from Pichia angusta. We designed cysteine mutants for labelling with the fluorescence dyes to probe the distances of the mutants to the membrane. These measurements support a model for PROPPIN-membrane binding, where the PROPPIN sits in a perpendicular or slightly tilted orientation on the membrane. Stopped-flow measurements suggest that initial PROPPIN-membrane binding is driven by non-specific PIP interactions. The FRRG motif then retains the protein in the membrane by binding two PIP molecules as evident by a lower dissociation rate for Atg18 in comparison with its PIP binding deficient FTTG mutant. We demonstrate that the amine-specific cross-linker Bis(sulfosuccinimidyl)suberate (BS3), which is used for protein-protein cross-linking can also be applied for cross-linking proteins and phosphatidylethanolamine (PE). Cross-linking experiments with liposome bound Atg18 yielded several PE cross-linked peptides. We also observed intermolecular cross-linked peptides, which indicated Atg18 oligomerization. FRET-based stopped-flow measurements revealed that Atg18 rapidly oligomerizes upon membrane binding while it is mainly monomeric in solution.
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http://dx.doi.org/10.1038/s41598-017-14337-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5656675PMC
October 2017

Analyzing Protein-Phosphoinositide Interactions with Liposome Flotation Assays.

Methods Mol Biol 2016 ;1376:155-62

Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.

Liposome flotation assays are a convenient tool to study protein-phosphoinositide interactions. Working with liposomes resembles physiological conditions more than protein-lipid overlay assays, which makes this method less prone to detect false positive interactions. However, liposome lipid composition must be well-considered in order to prevent nonspecific binding of the protein through electrostatic interactions with negatively charged lipids like phosphatidylserine. In this protocol we use the PROPPIN Hsv2 (homologous with swollen vacuole phenotype 2) as an example to demonstrate the influence of liposome lipid composition on binding and show how phosphoinositide binding specificities of a protein can be characterized with this method.
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http://dx.doi.org/10.1007/978-1-4939-3170-5_13DOI Listing
August 2016

Characterization of PROPPIN-Phosphoinositide Binding and Role of Loop 6CD in PROPPIN-Membrane Binding.

Biophys J 2015 May;108(9):2223-34

Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany. Electronic address:

PROPPINs (β-propellers that bind polyphosphoinositides) are a family of PtdIns3P- and PtdIns(3,5)P2-binding proteins that play an important role in autophagy. We analyzed PROPPIN-membrane binding through isothermal titration calorimetry (ITC), stopped-flow measurements, mutagenesis studies, and molecular dynamics (MD) simulations. ITC measurements showed that the yeast PROPPIN family members Atg18, Atg21, and Hsv2 bind PtdIns3P and PtdIns(3,5)P2 with high affinities in the nanomolar to low-micromolar range and have two phosphoinositide (PIP)-binding sites. Single PIP-binding site mutants have a 15- to 30-fold reduced affinity, which explains the requirement of two PIP-binding sites in PROPPINs. Hsv2 bound small unilamellar vesicles with a higher affinity than it bound large unilamellar vesicles in stopped-flow measurements. Thus, we conclude that PROPPIN membrane binding is curvature dependent. MD simulations revealed that loop 6CD is an anchor for membrane binding, as it is the region of the protein that inserts most deeply into the lipid bilayer. Mutagenesis studies showed that both hydrophobic and electrostatic interactions are required for membrane insertion of loop 6CD. We propose a model for PROPPIN-membrane binding in which PROPPINs are initially targeted to membranes through nonspecific electrostatic interactions and are then retained at the membrane through PIP binding.
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http://dx.doi.org/10.1016/j.bpj.2015.03.045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423041PMC
May 2015

Qualitative and quantitative characterization of protein-phosphoinositide interactions with liposome-based methods.

Autophagy 2013 May 27;9(5):770-7. Epub 2013 Feb 27.

Department of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.

We characterized phosphoinositide binding of the S. cerevisiae PROPPIN Hsv2 qualitatively with density flotation assays and quantitatively through isothermal titration calorimetry (ITC) measurements using liposomes. We discuss the design of these experiments and show with liposome flotation assays that Hsv2 binds with high specificity to both PtdIns3P and PtdIns(3,5)P 2. We propose liposome flotation assays as a more accurate alternative to the commonly used PIP strips for the characterization of phosphoinositide-binding specificities of proteins. We further quantitatively characterized PtdIns3P binding of Hsv2 with ITC measurements and determined a dissociation constant of 0.67 µM and a stoichiometry of 2:1 for PtdIns3P binding to Hsv2. PtdIns3P is crucial for the biogenesis of autophagosomes and their precursors. Besides the PROPPINs there are other PtdIns3P binding proteins with a link to autophagy, which includes the FYVE-domain containing proteins ZFYVE1/DFCP1 and WDFY3/ALFY and the PX-domain containing proteins Atg20 and Snx4/Atg24. The methods described could be useful tools for the characterization of these and other phosphoinositide-binding proteins.
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http://dx.doi.org/10.4161/auto.23978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3669185PMC
May 2013

It takes two to tango: PROPPINs use two phosphoinositide-binding sites.

Autophagy 2013 Jan 15;9(1):106-7. Epub 2012 Oct 15.

Department of Biochemistry II, Georg-August University, Göttingen, Germany.

PROPPINs are a family of PtdIns3P and PtdIns(3,5)P 2-binding proteins. The crystal structure now unravels the presence of two distinct phosphoinositide-binding sites at the circumference of the seven bladed β-propeller. Mutagenesis analysis of the binding sites shows that both are required for normal membrane association and autophagic activities. We identified a set of evolutionarily conserved basic and polar residues within both binding pockets, which are crucial for phosphoinositide binding. We expect that membrane association of PROPPINs is further stabilized by membrane insertions and interactions with other proteins.
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http://dx.doi.org/10.4161/auto.22400DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3542210PMC
January 2013

Structural and functional characterization of the two phosphoinositide binding sites of PROPPINs, a β-propeller protein family.

Proc Natl Acad Sci U S A 2012 Jul 2;109(30):E2042-9. Epub 2012 Jul 2.

Department of Biochemistry II, Georg August University, D-37073 Göttingen, Germany.

β-propellers that bind polyphosphoinositides (PROPPINs), a eukaryotic WD-40 motif-containing protein family, bind via their predicted β-propeller fold the polyphosphoinositides PtdIns3P and PtdIns(3,5)P(2) using a conserved FRRG motif. PROPPINs play a key role in macroautophagy in addition to other functions. We present the 3.0-Å crystal structure of Kluyveromyces lactis Hsv2, which shares significant sequence homologies with its three Saccharomyces cerevisiae homologs Atg18, Atg21, and Hsv2. It adopts a seven-bladed β-propeller fold with a rare nonvelcro propeller closure. Remarkably, in the crystal structure, the two arginines of the FRRG motif are part of two distinct basic pockets formed by a set of highly conserved residues. In comprehensive in vivo and in vitro studies of ScAtg18 and ScHsv2, we define within the two pockets a set of conserved residues essential for normal membrane association, phosphoinositide binding, and biological activities. Our experiments show that PROPPINs contain two individual phosphoinositide binding sites. Based on docking studies, we propose a model for phosphoinositide binding of PROPPINs.
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http://dx.doi.org/10.1073/pnas.1205128109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3409749PMC
July 2012

SeSaM-Tv-II generates a protein sequence space that is unobtainable by epPCR.

Chembiochem 2011 Jul 10;12(10):1595-601. Epub 2011 Jun 10.

Biotechnology, RWTH Aachen University, Aachen, Germany.

Generating high-quality mutant libraries in which each amino acid is equally targeted and substituted in a chemically diverse manner is crucial to obtain improved variants in small mutant libraries. The sequence saturation mutagenesis method (SeSaM-Tv(+) ) offers the opportunity to generate such high-quality mutant libraries by introducing consecutive mutations and by enriching transversions. In this study, automated gel electrophoresis, real-time quantitative PCR, and a phosphorimager quantification system were developed and employed to optimize each step of previously reported SeSaM-Tv(+) method. Advancements of the SeSaM-Tv(+) protocol and the use of a novel DNA polymerase quadrupled the number of transversions, by doubling the fraction of consecutive mutations (from 16.7 to 37.1 %). About 33 % of all amino acid substitutions observed in a model library are rarely introduced by epPCR methods, and around 10 % of all clones carried amino acid substitutions that are unobtainable by epPCR.
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http://dx.doi.org/10.1002/cbic.201100010DOI Listing
July 2011

Ultrahigh-throughput screening system for directed glucose oxidase evolution in yeast cells.

Comb Chem High Throughput Screen 2011 Jan;14(1):55-60

RWTH Aachen University, Lehrstuhl für Biotechnologie, Worringer Weg 1, 52056 Aachen, Germany.

A compartmentalized tyramide labeling system (CoaTi) employing flow cytometry for sorting of yeast cells was developed as ultrahigh-throughput screening for Glucose oxidase (GOx) from Aspergillus niger. CoaTi combines in vitro compartmentalization technology with the CARD reporter system which uses fluorescein tyramide labels for detection of peroxidase activity. Physical connection between cells and fluorescein tyramide radicals was achieved by compartmentalization of yeast cells inside microdroplets of single water-in-oil emulsions. After reaction cells were recovered from single emulsions and sorted by flow cytometry, an error prone PCR mutant library of Glucose oxidase (GOx) containing 10(7) cells and ~10(5) of different GOx variants was screened. Mutagenic conditions of GOx mutant library were selected to generate <1 % of active GOx population in order to explore influence of high mutation frequency on GOx activity. GOx variant Mut12 that contains 5 mutations (N2Y, K13E, T30V, I94V, K152R) showed a 1.2 times decreased K(m) (22.0 vs 18.1 mM) and a 2.7 fold increased k(cat) (150 s(-1) vs 54.8 s(-1)) compared to wt GOx. Compared to the employed parent B11 GOx (16 mM, 80 s(-1)) it has a slightly increased K(m) and 1.8 times increased k(cat).
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http://dx.doi.org/10.2174/1386207311107010055DOI Listing
January 2011