1
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Füllbrunn N, Nicastro R, Mari M, Griffith J, Herrmann E, Rasche R, Borchers AC, Auffarth K, Kümmel D, Reggiori F, De Virgilio C, Langemeyer L, Ungermann C. The GTPase activating protein Gyp7 regulates Rab7/Ypt7 activity on late endosomes. J Cell Biol 2024; 223:e202305038. [PMID: 38536036 PMCID: PMC10978497 DOI: 10.1083/jcb.202305038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 01/22/2024] [Accepted: 03/08/2024] [Indexed: 04/01/2024] Open
Abstract
Organelles of the endomembrane system contain Rab GTPases as identity markers. Their localization is determined by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). It remains largely unclear how these regulators are specifically targeted to organelles and how their activity is regulated. Here, we focus on the GAP Gyp7, which acts on the Rab7-like Ypt7 protein in yeast, and surprisingly observe the protein exclusively in puncta proximal to the vacuole. Mistargeting of Gyp7 to the vacuole strongly affects vacuole morphology, suggesting that endosomal localization is needed for function. In agreement, efficient endolysosomal transport requires Gyp7. In vitro assays reveal that Gyp7 requires a distinct lipid environment for membrane binding and activity. Overexpression of Gyp7 concentrates Ypt7 in late endosomes and results in resistance to rapamycin, an inhibitor of the target of rapamycin complex 1 (TORC1), suggesting that these late endosomes are signaling endosomes. We postulate that Gyp7 is part of regulatory machinery involved in late endosome function.
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Affiliation(s)
- Nadia Füllbrunn
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Muriel Mari
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Janice Griffith
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - René Rasche
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Ann-Christin Borchers
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Cell Biology, University Medical Center Utrecht, Utrecht, Netherlands
| | | | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, Osnabrück, Germany
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2
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Rasche R, Apken LH, Michalke E, Kümmel D, Oeckinghaus A. κB-Ras proteins are fast-exchanging GTPases and function via nucleotide-independent binding of Ral GTPase-activating protein complexes. FEBS Lett 2024. [PMID: 38604989 DOI: 10.1002/1873-3468.14860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/29/2024] [Accepted: 02/27/2024] [Indexed: 04/13/2024]
Abstract
κB-Ras (NF-κB inhibitor-interacting Ras-like protein) GTPases are small Ras-like GTPases but harbor interesting differences in important sequence motifs. They act in a tumor-suppressive manner as negative regulators of Ral (Ras-like) GTPase and NF-κB signaling, but little is known about their mode of function. Here, we demonstrate that, in contrast to predictions based on primary structure, κB-Ras GTPases possess hydrolytic activity. Combined with low nucleotide affinity, this renders them fast-cycling GTPases that are predominantly GTP-bound in cells. We characterize the impact of κB-Ras mutations occurring in tumors and demonstrate that nucleotide binding affects κB-Ras stability but is not strictly required for RalGAP (Ral GTPase-activating protein) binding. This demonstrates that κB-Ras control of RalGAP/Ral signaling occurs in a nucleotide-binding- and switch-independent fashion.
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Affiliation(s)
- René Rasche
- Institute of Biochemistry, University Münster, Germany
| | | | - Esther Michalke
- Institute of Molecular Tumor Biology, University Münster, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University Münster, Germany
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3
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Titze S, Kümmel D. The difference is in the details: Structural and mechanistic variations in the LAMTOR-Gtr/Rag module. Structure 2023; 31:1010-1012. [PMID: 37683616 DOI: 10.1016/j.str.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/04/2023] [Accepted: 08/04/2023] [Indexed: 09/10/2023]
Abstract
In this issue of Structure, Tettoni et al. present the structure and biochemical characterization of the fission yeast LAMTOR-Gtr complex, which mediates nutrient-dependent control of cell growth. The study reveals specific differences to the homologous human LAMTOR-Rag complex that might represent means of evolutionary adaptation.
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Affiliation(s)
- Sonja Titze
- Institute of Biochemistry, University of Münster, 48149 Münster, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, 48149 Münster, Germany.
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4
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Füsser FT, Wollenhaupt J, Weiss MS, Kümmel D, Koch O. Novel starting points for fragment-based drug design against mycobacterial thioredoxin reductase identified using crystallographic fragment screening. Acta Crystallogr D Struct Biol 2023; 79:857-865. [PMID: 37574972 PMCID: PMC10478635 DOI: 10.1107/s2059798323005223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
The increasing number of people dying from tuberculosis and the existence of extensively drug-resistant strains has led to an urgent need for new antituberculotic drugs with alternative modes of action. As part of the thioredoxin system, thioredoxin reductase (TrxR) is essential for the survival of Mycobacterium tuberculosis (Mtb) and shows substantial differences from human TrxR, making it a promising and most likely selective target. As a model organism for Mtb, crystals of Mycobacterium smegmatis TrxR that diffracted to high resolution were used in crystallographic fragment screening to discover binding fragments and new binding sites. The application of the 96 structurally diverse fragments from the F2X-Entry Screen revealed 56 new starting points for fragment-based drug design of new TrxR inhibitors. Over 200 crystal structures were analyzed using FragMAXapp, which includes processing and refinement by largely automated software pipelines and hit identification via the multi-data-set analysis approach PanDDA. The fragments are bound to 11 binding sites, of which four are positioned at binding pockets or important interaction sites and therefore show high potential for possible inhibition of TrxR.
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Affiliation(s)
- Friederike T. Füsser
- Institute of Pharmaceutical and Medicinal Chemistry, Münster University, Corrensstrasse 48, 48149 Münster, Germany
- German Center of Infection Research, Münster University, Corrensstrasse 48, 48149 Münster, Germany
- Institute of Biochemistry, Münster University, Corrensstrasse 36, 48149 Münster, Germany
| | - Jan Wollenhaupt
- Macromolecular Crystallography Group, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Manfred S. Weiss
- Macromolecular Crystallography Group, Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, Münster University, Corrensstrasse 36, 48149 Münster, Germany
| | - Oliver Koch
- Institute of Pharmaceutical and Medicinal Chemistry, Münster University, Corrensstrasse 48, 48149 Münster, Germany
- German Center of Infection Research, Münster University, Corrensstrasse 48, 48149 Münster, Germany
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5
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Wilmes S, Kümmel D. Insights into the role of the membranes in Rab GTPase regulation. Curr Opin Cell Biol 2023; 83:102177. [PMID: 37327649 DOI: 10.1016/j.ceb.2023.102177] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 06/18/2023]
Abstract
Rab GTPases are molecular switches with essential roles in mediating vesicular trafficking and establishing organelle identity. The conversion from the inactive, cytosolic to the membrane-bound, active species and back is tightly controlled by regulatory proteins. Recently, the roles of membrane properties and lipid composition of different target organelles in determining the activity state of Rabs have come to light. The investigation of several Rab guanine nucleotide exchange factors (GEFs) has revealed principles of how the recruitment via lipid interactions and the spatial confinement on the membrane surface contribute to spatiotemporal specificity in the Rab GTPase network. This paints an intricate picture of the control mechanisms in Rab activation and highlights the importance of the membrane lipid code in the organization of the endomembrane system.
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Affiliation(s)
- Stephan Wilmes
- University of Münster, Institute of Biochemistry, Corrensstraße 36, 48149 Münster, Germany
| | - Daniel Kümmel
- University of Münster, Institute of Biochemistry, Corrensstraße 36, 48149 Münster, Germany.
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6
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Borchers AC, Janz M, Schäfer JH, Moeller A, Kümmel D, Paululat A, Ungermann C, Langemeyer L. Regulatory sites in the Mon1-Ccz1 complex control Rab5 to Rab7 transition and endosome maturation. Proc Natl Acad Sci U S A 2023; 120:e2303750120. [PMID: 37463208 PMCID: PMC10372576 DOI: 10.1073/pnas.2303750120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/15/2023] [Indexed: 07/20/2023] Open
Abstract
Maturation from early to late endosomes depends on the exchange of their marker proteins Rab5 to Rab7. This requires Rab7 activation by its specific guanine nucleotide exchange factor (GEF) Mon1-Ccz1. Efficient GEF activity of this complex on membranes depends on Rab5, thus driving Rab-GTPase exchange on endosomes. However, molecular details on the role of Rab5 in Mon1-Ccz1 activation are unclear. Here, we identify key features in Mon1 involved in GEF regulation. We show that the intrinsically disordered N-terminal domain of Mon1 autoinhibits Rab5-dependent GEF activity on membranes. Consequently, Mon1 truncations result in higher GEF activity in vitro and alterations in early endosomal structures in Drosophila nephrocytes. A shift from Rab5 to more Rab7-positive structures in yeast suggests faster endosomal maturation. Using modeling, we further identify a conserved Rab5-binding site in Mon1. Mutations impairing Rab5 interaction result in poor GEF activity on membranes and growth defects in vivo. Our analysis provides a framework to understand the mechanism of Ras-related in brain (Rab) conversion and organelle maturation along the endomembrane system.
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Affiliation(s)
- Ann-Christin Borchers
- Biochemistry section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
| | - Maren Janz
- Zoology and Developmental Biology section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
| | - Jan-Hannes Schäfer
- Structural Biology section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
| | - Arne Moeller
- Structural Biology section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, 48149 Münster, Germany
| | - Achim Paululat
- Zoology and Developmental Biology section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
| | - Christian Ungermann
- Biochemistry section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, 49076 Osnabrück, Germany
| | - Lars Langemeyer
- Biochemistry section, Department of Biology/Chemistry, Osnabrück University, 49076 Osnabrück, Germany
- Center of Cellular Nanoanalytics, Osnabrück University, 49076 Osnabrück, Germany
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7
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Mhaindarkar VP, Rasche R, Kümmel D, Rudolph MG, Klostermeier D. Structure of reverse gyrase with a minimal latch that supports ATP-dependent positive supercoiling without specific interactions with the topoisomerase domain. Acta Crystallogr D Struct Biol 2023:S2059798323002565. [PMID: 37204816 DOI: 10.1107/s2059798323002565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023] Open
Abstract
Reverse gyrase is the only topoisomerase that introduces positive supercoils into DNA in an ATP-dependent reaction. Positive DNA supercoiling becomes possible through the functional cooperation of the N-terminal helicase domain of reverse gyrase with its C-terminal type IA topoisomerase domain. This cooperation is mediated by a reverse-gyrase-specific insertion into the helicase domain termed the `latch'. The latch consists of a globular domain inserted at the top of a β-bulge loop that connects this globular part to the helicase domain. While the globular domain shows little conservation in sequence and length and is dispensable for DNA supercoiling, the β-bulge loop is required for supercoiling activity. It has previously been shown that the β-bulge loop constitutes a minimal latch that couples ATP-dependent processes in the helicase domain to DNA processing by the topoisomerase domain. Here, the crystal structure of Thermotoga maritima reverse gyrase with such a β-bulge loop as a minimal latch is reported. It is shown that the β-bulge loop supports ATP-dependent DNA supercoiling of reverse gyrase without engaging in specific interactions with the topoisomerase domain. When only a small latch or no latch is present, a helix in the nearby helicase domain of T. maritima reverse gyrase partially unfolds. Comparison of the sequences and predicted structures of latch regions in other reverse gyrases shows that neither sequence nor structure are decisive factors for latch functionality; instead, the decisive factors are likely to be electrostatics and plain steric bulk.
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Affiliation(s)
- Vaibhav P Mhaindarkar
- Institute for Physical Chemistry, University of Muenster, Corrensstrasse 30, 48149 Muenster, Germany
| | - René Rasche
- Institute for Biochemistry, University of Muenster, Corrensstrasse 36, 48149 Muenster, Germany
| | - Daniel Kümmel
- Institute for Biochemistry, University of Muenster, Corrensstrasse 36, 48149 Muenster, Germany
| | - Markus G Rudolph
- Pharma Research and Early Development, Molecular Design and Chemical Biology, Hoffmann-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Dagmar Klostermeier
- Institute for Physical Chemistry, University of Muenster, Corrensstrasse 30, 48149 Muenster, Germany
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8
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Pasch T, Schröder A, Kattelmann S, Eisenstein M, Pietrokovski S, Kümmel D, Mootz HD. Structural and biochemical analysis of a novel atypically split intein reveals a conserved histidine specific to cysteine-less inteins. Chem Sci 2023; 14:5204-5213. [PMID: 37206380 PMCID: PMC10189870 DOI: 10.1039/d3sc01200j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 04/23/2023] [Indexed: 05/21/2023] Open
Abstract
Protein trans-splicing mediated by a split intein reconstitutes a protein backbone from two parts. This virtually traceless autoprocessive reaction provides the basis for numerous protein engineering applications. Protein splicing typically proceeds through two thioester or oxyester intermediates involving the side chains of cysteine or serine/threonine residues. A cysteine-less split intein has recently attracted particular interest as it can splice under oxidizing conditions and is orthogonal to disulfide or thiol bioconjugation chemistries. Here, we report the split PolB16 OarG intein, a second such cysteine-independent intein. As a unique trait, it is atypically split with a short intein-N precursor fragment of only 15 amino acids, the shortest characterized to date, which was chemically synthesized to enable protein semi-synthesis. By rational engineering we obtained a high-yielding, improved split intein mutant. Structural and mutational analysis revealed the dispensability of the usually crucial conserved motif N3 (block B) histidine as an obvious peculiar property. Unexpectedly, we identified a previously unnoticed histidine in hydrogen-bond forming distance to the catalytic serine 1 as critical for splicing. This histidine has been overlooked so far in multiple sequence alignments and is highly conserved only in cysteine-independent inteins as a part of a newly discovered motif NX. The motif NX histidine is thus likely of general importance to the specialized environment in the active site required in this intein subgroup. Together, our study advances the toolbox as well as the structural and mechanistic understanding of cysteine-less inteins.
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Affiliation(s)
- Tim Pasch
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Alexander Schröder
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Sabrina Kattelmann
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Miriam Eisenstein
- Department of Molecular Genetics, Weizmann Institute of Science Rehovot 76100 Israel
| | - Shmuel Pietrokovski
- Department of Molecular Genetics, Weizmann Institute of Science Rehovot 76100 Israel
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
| | - Henning D Mootz
- Institute of Biochemistry, University of Münster Corrensstr. 36 48149 Münster Germany
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9
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Herrmann E, Schäfer JH, Wilmes S, Ungermann C, Moeller A, Kümmel D. Structure of the metazoan Rab7 GEF complex Mon1-Ccz1-Bulli. Proc Natl Acad Sci U S A 2023; 120:e2301908120. [PMID: 37155863 DOI: 10.1073/pnas.2301908120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
The endosomal system of eukaryotic cells represents a central sorting and recycling compartment linked to metabolic signaling and the regulation of cell growth. Tightly controlled activation of Rab GTPases is required to establish the different domains of endosomes and lysosomes. In metazoans, Rab7 controls endosomal maturation, autophagy, and lysosomal function. It is activated by the guanine nucleotide exchange factor (GEF) complex Mon1-Ccz1-Bulli (MCBulli) of the tri-longin domain (TLD) family. While the Mon1 and Ccz1 subunits have been shown to constitute the active site of the complex, the role of Bulli remains elusive. We here present the cryo-electron microscopy (cryo-EM) structure of MCBulli at 3.2 Å resolution. Bulli associates as a leg-like extension at the periphery of the Mon1 and Ccz1 heterodimers, consistent with earlier reports that Bulli does not impact the activity of the complex or the interactions with recruiter and substrate GTPases. While MCBulli shows structural homology to the related ciliogenesis and planar cell polarity effector (Fuzzy-Inturned-Wdpcp) complex, the interaction of the TLD core subunits Mon1-Ccz1 and Fuzzy-Inturned with Bulli and Wdpcp, respectively, is remarkably different. The variations in the overall architecture suggest divergent functions of the Bulli and Wdpcp subunits. Based on our structural analysis, Bulli likely serves as a recruitment platform for additional regulators of endolysosomal trafficking to sites of Rab7 activation.
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Affiliation(s)
- Eric Herrmann
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, 48149 Münster, Germany
| | - Jan-Hannes Schäfer
- Department of Biology/Chemistry, Structural Biology section, Osnabrück University, 49076 Osnabrück, Germany
| | - Stephan Wilmes
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, 48149 Münster, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry section, Osnabrück University, 49076 Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück, Osnabrück University, 49076 Osnabrück, Germany
| | - Arne Moeller
- Department of Biology/Chemistry, Structural Biology section, Osnabrück University, 49076 Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück, Osnabrück University, 49076 Osnabrück, Germany
| | - Daniel Kümmel
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, 48149 Münster, Germany
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10
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Herrmann E, Langemeyer L, Auffarth K, Ungermann C, Kümmel D. Targeting of the Mon1-Ccz1 Rab guanine nucleotide exchange factor to distinct organelles by a synergistic protein and lipid code. J Biol Chem 2023; 299:102915. [PMID: 36649906 PMCID: PMC10124900 DOI: 10.1016/j.jbc.2023.102915] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 01/01/2023] [Accepted: 01/05/2023] [Indexed: 01/16/2023] Open
Abstract
Activation of the small GTPase Rab7 by its cognate guanine nucleotide exchange factor Mon1-Ccz1 (MC1) is a key step in the maturation of endosomes and autophagosomes. This process is tightly regulated and subject to precise spatiotemporal control of MC1 localization, but the mechanisms that underly MC1 localization have not been fully elucidated. We here identify and characterize an amphipathic helix in Ccz1, which is required for the function of Mon-Ccz1 in autophagy, but not endosomal maturation. Furthermore, our data show that the interaction of the Ccz1 amphipathic helix with lipid packing defects, binding of Mon1 basic patches to positively charged lipids, and association of MC1 with recruiter proteins collectively govern membrane recruitment of the complex in a synergistic and redundant manner. Membrane binding enhances MC1 activity predominantly by increasing enzyme and substrate concentration on the membrane, but interaction with recruiter proteins can further stimulate the guanine nucleotide exchange factor. Our data demonstrate that specific protein and lipid cues convey the differential targeting of MC1 to endosomes and autophagosomes. In conclusion, we reveal the molecular basis for how MC1 is adapted to recognize distinct target compartments by exploiting the unique biophysical properties of organelle membranes and thus provide a model for how the complex is regulated and activated independently in different functional contexts.
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Affiliation(s)
- Eric Herrmann
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany; Center of Cellular Nanoanalytics (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany.
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11
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Gollwitzer P, Grützmacher N, Wilhelm S, Kümmel D, Demetriades C. Author Correction: A Rag GTPase dimer code defines the regulation of mTORC1 by amino acids. Nat Cell Biol 2023; 25:366. [PMID: 36536178 PMCID: PMC9928581 DOI: 10.1038/s41556-022-01073-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Peter Gollwitzer
- grid.419502.b0000 0004 0373 6590Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Nina Grützmacher
- grid.419502.b0000 0004 0373 6590Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Sabine Wilhelm
- grid.419502.b0000 0004 0373 6590Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany
| | - Daniel Kümmel
- grid.5949.10000 0001 2172 9288Institute of Biochemistry, University of Münster, Münster, Germany
| | - Constantinos Demetriades
- Max Planck Institute for Biology of Ageing (MPI-AGE), Cologne, Germany. .,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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12
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Kümmel D, Herrmann E, Langemeyer L, Ungermann C. Molecular insights into endolysosomal microcompartment formation and maintenance. Biol Chem 2022; 404:441-454. [PMID: 36503831 DOI: 10.1515/hsz-2022-0294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022]
Abstract
Abstract
The endolysosomal system of eukaryotic cells has a key role in the homeostasis of the plasma membrane, in signaling and nutrient uptake, and is abused by viruses and pathogens for entry. Endocytosis of plasma membrane proteins results in vesicles, which fuse with the early endosome. If destined for lysosomal degradation, these proteins are packaged into intraluminal vesicles, converting an early endosome to a late endosome, which finally fuses with the lysosome. Each of these organelles has a unique membrane surface composition, which can form segmented membrane microcompartments by membrane contact sites or fission proteins. Furthermore, these organelles are in continuous exchange due to fission and fusion events. The underlying machinery, which maintains organelle identity along the pathway, is regulated by signaling processes. Here, we will focus on the Rab5 and Rab7 GTPases of early and late endosomes. As molecular switches, Rabs depend on activating guanine nucleotide exchange factors (GEFs). Over the last years, we characterized the Rab7 GEF, the Mon1-Ccz1 (MC1) complex, and key Rab7 effectors, the HOPS complex and retromer. Structural and functional analyses of these complexes lead to a molecular understanding of their function in the context of organelle biogenesis.
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Affiliation(s)
- Daniel Kümmel
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
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13
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Shvarev D, Schoppe J, König C, Perz A, Füllbrunn N, Kiontke S, Langemeyer L, Januliene D, Schnelle K, Kümmel D, Fröhlich F, Moeller A, Ungermann C. Structure of the HOPS tethering complex, a lysosomal membrane fusion machinery. eLife 2022; 11:80901. [PMID: 36098503 PMCID: PMC9592082 DOI: 10.7554/elife.80901] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/12/2022] [Indexed: 11/17/2022] Open
Abstract
Lysosomes are essential for cellular recycling, nutrient signaling, autophagy, and pathogenic bacteria and viruses invasion. Lysosomal fusion is fundamental to cell survival and requires HOPS, a conserved heterohexameric tethering complex. On the membranes to be fused, HOPS binds small membrane-associated GTPases and assembles SNAREs for fusion, but how the complex fulfills its function remained speculative. Here, we used cryo-electron microscopy to reveal the structure of HOPS. Unlike previously reported, significant flexibility of HOPS is confined to its extremities, where GTPase binding occurs. The SNARE-binding module is firmly attached to the core, therefore, ideally positioned between the membranes to catalyze fusion. Our data suggest a model for how HOPS fulfills its dual functionality of tethering and fusion and indicate why it is an essential part of the membrane fusion machinery. Our cells break down the nutrients that they receive from the body to create the building blocks needed to keep us alive. This is done by compartments called lysosomes that are filled with a cocktail of proteins called enzymes, which speed up the breakdown process. Lysosomes are surrounded by a membrane, a barrier of fatty molecules that protects the rest of the cell from being digested. When new nutrients reach the cell, they travel to the lysosome packaged in vesicles, which have their own fatty membrane. To allow the nutrients to enter the lysosome without creating a leak, the membranes of the vesicles and the lysosome must fuse. The mechanism through which these membranes fuse is not fully clear. It is known that both fusing membranes must contain proteins called SNAREs, which wind around each other when they interact. However, this alone is not enough. Other proteins are also required to tether the membranes together before they fuse. To understand how these tethers play a role, Shvarev, Schoppe, König et al. studied the structure of the HOPS complex from yeast. This assembly of six proteins is vital for lysosomal fusion and, has a composition similar to the equivalent complex in humans. Using cryo-electron microscopy, a technique that relies on freezing purified proteins to image them with an electron microscope and reveal their structure, allowed Shvarev, Schoppe, König et al. to provide a model for how HOPS interacts with SNAREs and membranes. In addition to HOPS acting as a tether to bring the membranes together, it can also bind directly to SNAREs. This creates a bridge that allows the proteins to wrap around each other, driving the membranes to fuse. HOPS is a crucial component in the cellular machinery, and mutations in the complex can cause devastating neurological defects. The complex is also targeted by viruses – such as SARS-CoV-2 – that manipulate HOPS to reduce its activity. Shvarev, Schoppe, König et al.’s findings could help researchers to develop drugs to maintain or recover the activity of HOPS. However, this will require additional information about its structure and how the complex acts in the biological environment of the cell.
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Affiliation(s)
- Dmitry Shvarev
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Jannis Schoppe
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Caroline König
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Angela Perz
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Nadia Füllbrunn
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Stephan Kiontke
- Department of Plant Physiology and Photo Biology, Philipp University of Marburg, Marburg, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Dovile Januliene
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Kilian Schnelle
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Daniel Kümmel
- Department of Chemistry and Pharmacy, University of Münster, Münster, Germany
| | - Florian Fröhlich
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
| | - Arne Moeller
- Department of Biology/Chemistry, Osnabrück University, Osnabrück, Germany
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14
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Garabedian NT, Schreiber PJ, Brandt N, Zschumme P, Blatter IL, Dollmann A, Haug C, Kümmel D, Li Y, Meyer F, Morstein CE, Rau JS, Weber M, Schneider J, Gumbsch P, Selzer M, Greiner C. Generating FAIR research data in experimental tribology. Sci Data 2022. [PMCID: PMC9203546 DOI: 10.1038/s41597-022-01429-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Solutions for the generation of FAIR (Findable, Accessible, Interoperable, and Reusable) data and metadata in experimental tribology are currently lacking. Nonetheless, FAIR data production is a promising path for implementing scalable data science techniques in tribology, which can lead to a deeper understanding of the phenomena that govern friction and wear. Missing community-wide data standards, and the reliance on custom workflows and equipment are some of the main challenges when it comes to adopting FAIR data practices. This paper, first, outlines a sample framework for scalable generation of FAIR data, and second, delivers a showcase FAIR data package for a pin-on-disk tribological experiment. The resulting curated data, consisting of 2,008 key-value pairs and 1,696 logical axioms, is the result of (1) the close collaboration with developers of a virtual research environment, (2) crowd-sourced controlled vocabulary, (3) ontology building, and (4) numerous – seemingly – small-scale digital tools. Thereby, this paper demonstrates a collection of scalable non-intrusive techniques that extend the life, reliability, and reusability of experimental tribological data beyond typical publication practices.
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15
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Peters A, Herrmann E, Cornelissen NV, Klöcker N, Kümmel D, Rentmeister A. Visible-Light Removable Photocaging Groups Accepted by MjMAT Variant: Structural Basis and Compatibility with DNA and RNA Methyltransferases. Chembiochem 2021; 23:e202100437. [PMID: 34606675 PMCID: PMC9298006 DOI: 10.1002/cbic.202100437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/01/2021] [Indexed: 12/20/2022]
Abstract
Methylation and demethylation of DNA, RNA and proteins constitutes a major regulatory mechanism in epigenetic processes. Investigations would benefit from the ability to install photo‐cleavable groups at methyltransferase target sites that block interactions with reader proteins until removed by non‐damaging light in the visible spectrum. Engineered methionine adenosyltransferases (MATs) have been exploited in cascade reactions with methyltransferases (MTases) to modify biomolecules with non‐natural groups, including first evidence for accepting photo‐cleavable groups. We show that an engineered MAT from Methanocaldococcus jannaschii (PC‐MjMAT) is 308‐fold more efficient at converting ortho‐nitrobenzyl‐(ONB)‐homocysteine than the wildtype enzyme. PC‐MjMAT is active over a broad range of temperatures and compatible with MTases from mesophilic organisms. We solved the crystal structures of wildtype and PC‐MjMAT in complex with AdoONB and a red‐shifted derivative thereof. These structures reveal that aromatic stacking interactions within the ligands are key to accommodating the photocaging groups in PC‐MjMAT. The enlargement of the binding pocket eliminates steric clashes to enable AdoMet analogue binding. Importantly, PC‐MjMAT exhibits remarkable activity on methionine analogues with red‐shifted ONB‐derivatives enabling photo‐deprotection of modified DNA by visible light.
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Affiliation(s)
- Aileen Peters
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Eric Herrmann
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Nicolas V Cornelissen
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Nils Klöcker
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Daniel Kümmel
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Andrea Rentmeister
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
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16
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Michailidou F, Klöcker N, Cornelissen NV, Singh RK, Peters A, Ovcharenko A, Kümmel D, Rentmeister A. Cover Picture: Engineered SAM Synthetases for Enzymatic Generation of AdoMet Analogs with Photocaging Groups and Reversible DNA Modification in Cascade Reactions (Angew. Chem. Int. Ed. 1/2021). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/anie.202015604] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Freideriki Michailidou
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
- Current address: ETH Zürich Department of Chemistry and Applied Biosciences Laboratory of Organic Chemistry Vladimir-Prelog-Weg 1–5/10 8093 Zürich Switzerland
| | - Nils Klöcker
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Nicolas V. Cornelissen
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Rohit K. Singh
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Aileen Peters
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Anna Ovcharenko
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Daniel Kümmel
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
| | - Andrea Rentmeister
- Department of Chemistry Institute of Biochemistry University of Münster Corrensstr. 36 48149 Münster Germany
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17
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Michailidou F, Klöcker N, Cornelissen NV, Singh RK, Peters A, Ovcharenko A, Kümmel D, Rentmeister A. Titelbild: Maßgeschneiderte SAM‐Synthetasen zur enzymatischen Herstellung von AdoMet‐Analoga mit Photoschutzgruppen und zur reversiblen DNA‐Modifizierung in Kaskadenreaktionen (Angew. Chem. 1/2021). Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202015604] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Freideriki Michailidou
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
- Derzeitige Adresse: ETH Zürich Fachbereich Chemie und angewandte Biowissenschaften Laboratorium für Organische Chemie Vladimir-Prelog-Weg 1–5/10 8093 Zürich Schweiz
| | - Nils Klöcker
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Nicolas V. Cornelissen
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Rohit K. Singh
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Aileen Peters
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Anna Ovcharenko
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Daniel Kümmel
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Andrea Rentmeister
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
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18
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Michailidou F, Klöcker N, Cornelissen NV, Singh RK, Peters A, Ovcharenko A, Kümmel D, Rentmeister A. Maßgeschneiderte SAM‐Synthetasen zur enzymatischen Herstellung von AdoMet‐Analoga mit Photoschutzgruppen und zur reversiblen DNA‐Modifizierung in Kaskadenreaktionen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012623] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Freideriki Michailidou
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
- Derzeitige Adresse: ETH Zürich Fachbereich Chemie und angewandte Biowissenschaften Laboratorium für Organische Chemie Vladimir-Prelog-Weg 1–5/10 8093 Zürich Schweiz
| | - Nils Klöcker
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Nicolas V. Cornelissen
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Rohit K. Singh
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Aileen Peters
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Anna Ovcharenko
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Daniel Kümmel
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
| | - Andrea Rentmeister
- Fachbereich Chemie Institut für Biochemie Universität von Münster Corrensstr. 36 48149 Münster Deutschland
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19
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Michailidou F, Klöcker N, Cornelissen NV, Singh RK, Peters A, Ovcharenko A, Kümmel D, Rentmeister A. Engineered SAM Synthetases for Enzymatic Generation of AdoMet Analogs with Photocaging Groups and Reversible DNA Modification in Cascade Reactions. Angew Chem Int Ed Engl 2020; 60:480-485. [PMID: 33017502 PMCID: PMC7839696 DOI: 10.1002/anie.202012623] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Indexed: 12/17/2022]
Abstract
Methylation and demethylation of DNA, RNA and proteins has emerged as a major regulatory mechanism. Studying the function of these modifications would benefit from tools for their site‐specific inhibition and timed removal. S‐Adenosyl‐L‐methionine (AdoMet) analogs in combination with methyltransferases (MTases) have proven useful to map or block and release MTase target sites, however their enzymatic generation has been limited to aliphatic groups at the sulfur atom. We engineered a SAM synthetase from Cryptosporidium hominis (PC‐ChMAT) for efficient generation of AdoMet analogs with photocaging groups that are not accepted by any WT MAT reported to date. The crystal structure of PC‐ChMAT at 1.87 Å revealed how the photocaged AdoMet analog is accommodated and guided engineering of a thermostable MAT from Methanocaldococcus jannaschii. PC‐MATs were compatible with DNA‐ and RNA‐MTases, enabling sequence‐specific modification (“writing”) of plasmid DNA and light‐triggered removal (“erasing”).
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Affiliation(s)
- Freideriki Michailidou
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany.,Current address: ETH Zürich, Department of Chemistry and Applied Biosciences, Laboratory of Organic Chemistry, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Nils Klöcker
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Nicolas V Cornelissen
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Rohit K Singh
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Aileen Peters
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Anna Ovcharenko
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Daniel Kümmel
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
| | - Andrea Rentmeister
- Department of Chemistry, Institute of Biochemistry, University of Münster, Corrensstr. 36, 48149, Münster, Germany
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20
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Lynagh T, Kiontke S, Meyhoff-Madsen M, Gless BH, Johannesen J, Kattelmann S, Christiansen A, Dufva M, Laustsen AH, Devkota K, Olsen CA, Kümmel D, Pless SA, Lohse B. Peptide Inhibitors of the α-Cobratoxin-Nicotinic Acetylcholine Receptor Interaction. J Med Chem 2020; 63:13709-13718. [PMID: 33143415 PMCID: PMC7705965 DOI: 10.1021/acs.jmedchem.0c01202] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
![]()
Venomous snakebites cause >100
000 deaths every year, in many cases
via potent depression of human neuromuscular signaling by snake α-neurotoxins.
Emergency therapy still relies on antibody-based antivenom, hampered
by poor access, frequent adverse reactions, and cumbersome production/purification.
Combining high-throughput discovery and subsequent structure–function
characterization, we present simple peptides that bind α-cobratoxin
(α-Cbtx) and prevent its inhibition of nicotinic acetylcholine
receptors (nAChRs) as a lead for the development of alternative antivenoms.
Candidate peptides were identified by phage display and deep sequencing,
and hits were characterized by electrophysiological recordings, leading
to an 8-mer peptide that prevented α-Cbtx inhibition of nAChRs.
We also solved the peptide:α-Cbtx cocrystal structure, revealing
that the peptide, although of unique primary sequence, binds to α-Cbtx
by mimicking structural features of the nAChR binding pocket. This
demonstrates the potential of small peptides to neutralize lethal
snake toxins in vitro, establishing a potential route to simple, synthetic,
low-cost antivenoms.
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Affiliation(s)
- Timothy Lynagh
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, 5008 Bergen, Norway.,Center for Biopharmaceuticals & Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Stephan Kiontke
- Division of Structural Biology, Department of Biology/Chemistry, University of Osnabrück, Barbarastraße 13, Osnabrück 49076, Germany.,Faculty of Biology, Department of Plant Physiology and Photobiology, Philipps-Universität Marburg, Karl-von-Frisch-Straße 8, 35032 Marburg, Germany
| | - Maria Meyhoff-Madsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Bengt H Gless
- Center for Biopharmaceuticals & Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Jónas Johannesen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Sabrina Kattelmann
- Institute of Biochemistry, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Anders Christiansen
- Fluid Array Systems and Technology, Nano and Bio-physical Systems, Department of Health Technology, Technical University of Denmark, Building 423 Produktionstorvet, DK-2800 Kongens Lyngby, Denmark
| | - Martin Dufva
- Fluid Array Systems and Technology, Nano and Bio-physical Systems, Department of Health Technology, Technical University of Denmark, Building 423 Produktionstorvet, DK-2800 Kongens Lyngby, Denmark
| | - Andreas H Laustsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Kanchan Devkota
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Christian A Olsen
- Center for Biopharmaceuticals & Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Daniel Kümmel
- Division of Structural Biology, Department of Biology/Chemistry, University of Osnabrück, Barbarastraße 13, Osnabrück 49076, Germany.,Institute of Biochemistry, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Stephan Alexander Pless
- Center for Biopharmaceuticals & Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Brian Lohse
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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21
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Hoffmann S, Terhorst TME, Singh RK, Kümmel D, Pietrokovski S, Mootz HD. Biochemical and Structural Characterization of an Unusual and Naturally Split Class 3 Intein. Chembiochem 2020; 22:364-373. [PMID: 32813312 PMCID: PMC7891396 DOI: 10.1002/cbic.202000509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/19/2020] [Indexed: 12/31/2022]
Abstract
Split inteins are indispensable tools for protein engineering because their ligation and cleavage reactions enable unique modifications of the polypeptide backbone. Three different classes of inteins have been identified according to the nature of the covalent intermediates resulting from the acyl rearrangements in the multistep protein‐splicing pathway. Class 3 inteins employ a characteristic internal cysteine for a branched thioester intermediate. A bioinformatic database search of non‐redundant protein sequences revealed the absence of split variants in 1701 class 3 inteins. We have discovered the first reported split class 3 intein in a metagenomics data set and report its biochemical, mechanistic and structural analysis. The AceL NrdHF intein exhibits low sequence conservation with other inteins and marked deviations in residues at conserved key positions, including a variation of the typical class‐3 WCT triplet motif. Nevertheless, functional analysis confirmed the class 3 mechanism of the intein and revealed excellent splicing yields within a few minutes over a wide range of conditions and with barely detectable cleavage side reactions. A high‐resolution crystal structure of the AceL NrdHF precursor and a mutagenesis study explained the importance and roles of several residues at the key positions. Tolerated substitutions in the flanking extein residues and a high affinity between the split intein fragments further underline the intein's future potential as a ligation tool.
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Affiliation(s)
- Simon Hoffmann
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Tobias M E Terhorst
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Rohit K Singh
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Shmuel Pietrokovski
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Henning D Mootz
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
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22
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Escobar-Hoyos LF, Penson A, Kannan R, Cho H, Pan CH, Singh RK, Apken LH, Hobbs GA, Luo R, Lecomte N, Babu S, Pan FC, Alonso-Curbelo D, Morris JP, Askan G, Grbovic-Huezo O, Ogrodowski P, Bermeo J, Saglimbeni J, Cruz CD, Ho YJ, Lawrence SA, Melchor JP, Goda GA, Bai K, Pastore A, Hogg SJ, Raghavan S, Bailey P, Chang DK, Biankin A, Shroyer KR, Wolpin BM, Aguirre AJ, Ventura A, Taylor B, Der CJ, Dominguez D, Kümmel D, Oeckinghaus A, Lowe SW, Bradley RK, Abdel-Wahab O, Leach SD. Altered RNA Splicing by Mutant p53 Activates Oncogenic RAS Signaling in Pancreatic Cancer. Cancer Cell 2020; 38:198-211.e8. [PMID: 32559497 PMCID: PMC8028848 DOI: 10.1016/j.ccell.2020.05.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/17/2020] [Accepted: 05/11/2020] [Indexed: 12/13/2022]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is driven by co-existing mutations in KRAS and TP53. However, how these mutations collaborate to promote this cancer is unknown. Here, we uncover sequence-specific changes in RNA splicing enforced by mutant p53 which enhance KRAS activity. Mutant p53 increases expression of splicing regulator hnRNPK to promote inclusion of cytosine-rich exons within GTPase-activating proteins (GAPs), negative regulators of RAS family members. Mutant p53-enforced GAP isoforms lose cell membrane association, leading to heightened KRAS activity. Preventing cytosine-rich exon inclusion in mutant KRAS/p53 PDACs decreases tumor growth. Moreover, mutant p53 PDACs are sensitized to inhibition of splicing via spliceosome inhibitors. These data provide insight into co-enrichment of KRAS and p53 mutations and therapeutics targeting this mechanism in PDAC.
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Affiliation(s)
- Luisa F Escobar-Hoyos
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Therapeutic Radiology, Yale University, School of Medicine, New Haven, CT 06520, USA; Department of Biology, Research Group Genetic Toxicology and Cytogenetics, School of Natural Sciences and Education, Universidad del Cauca, Popayán, Colombia; Department of Pathology, Renaissance School of Medicine, Stony Brook University, New York, NY 11794, USA.
| | - Alex Penson
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ram Kannan
- Howard Hughes Medical Institute, Cancer Biology & Genetics Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Hana Cho
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Chun-Hao Pan
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, New York, NY 11794, USA
| | - Rohit K Singh
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Lisa H Apken
- Institute of Molecular Tumor Biology, University of Münster, Münster, Germany
| | - G Aaron Hobbs
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Renhe Luo
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Nicolas Lecomte
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sruthi Babu
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, New York, NY 11794, USA
| | - Fong Cheng Pan
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Direna Alonso-Curbelo
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - John P Morris
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Gokce Askan
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Olivera Grbovic-Huezo
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Paul Ogrodowski
- Howard Hughes Medical Institute, Cancer Biology & Genetics Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jonathan Bermeo
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Joseph Saglimbeni
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Cristian D Cruz
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yu-Jui Ho
- Howard Hughes Medical Institute, Cancer Biology & Genetics Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Sharon A Lawrence
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jerry P Melchor
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Grant A Goda
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Karen Bai
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, New York, NY 11794, USA
| | - Alessandro Pastore
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Simon J Hogg
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Srivatsan Raghavan
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Peter Bailey
- Department of General Surgery, University of Heidelberg, Im Neuenheimer Feld 110, Heidelberg, Baden-Württemberg 69120, Germany; Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, G61 1Q, Glasgow, UK
| | - David K Chang
- The Kinghorn Cancer Centre, and the Cancer Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia; Department of Surgery, Bankstown Hospital, Eldridge Road, Bankstown, Sydney, NSW, Australia; South Western Sydney Clinical School, Faculty of Medicine, University of New South Wales, Liverpool, NSW, Australia
| | - Andrew Biankin
- Department of General Surgery, University of Heidelberg, Im Neuenheimer Feld 110, Heidelberg, Baden-Württemberg 69120, Germany; Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Bearsden, G61 1Q, Glasgow, UK; The Kinghorn Cancer Centre, and the Cancer Research Program, Garvan Institute of Medical Research, Darlinghurst, Sydney, NSW, Australia; Department of Surgery, Bankstown Hospital, Eldridge Road, Bankstown, Sydney, NSW, Australia
| | - Kenneth R Shroyer
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, New York, NY 11794, USA
| | - Brian M Wolpin
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA
| | - Andrew J Aguirre
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andrea Ventura
- Howard Hughes Medical Institute, Cancer Biology & Genetics Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Barry Taylor
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Departments of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Channing J Der
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniel Dominguez
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Daniel Kümmel
- Institute of Biochemistry, University of Münster, Münster, Germany
| | - Andrea Oeckinghaus
- Institute of Molecular Tumor Biology, University of Münster, Münster, Germany
| | - Scott W Lowe
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Howard Hughes Medical Institute, Cancer Biology & Genetics Program, Sloan-Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Robert K Bradley
- Fred Hutchinson Cancer Research Center Seattle, Seattle, WA 98109-1024, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Steven D Leach
- David M. Rubenstein Center for Pancreatic Cancer Research, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Dartmouth Norris Cotton Cancer Center, Lebanon, NH 03766, USA.
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23
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Hansmann P, Brückner A, Kiontke S, Berkenfeld B, Seebohm G, Brouillard P, Vikkula M, Jansen FE, Nellist M, Oeckinghaus A, Kümmel D. Structure of the TSC2 GAP Domain: Mechanistic Insight into Catalysis and Pathogenic Mutations. Structure 2020; 28:933-942.e4. [PMID: 32502382 DOI: 10.1016/j.str.2020.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/06/2020] [Accepted: 05/15/2020] [Indexed: 12/17/2022]
Abstract
The TSC complex is the cognate GTPase-activating protein (GAP) for the small GTPase Rheb and a crucial regulator of the mechanistic target of rapamycin complex 1 (mTORC1). Mutations in the TSC1 and TSC2 subunits of the complex cause tuberous sclerosis complex (TSC). We present the crystal structure of the catalytic asparagine-thumb GAP domain of TSC2. A model of the TSC2-Rheb complex and molecular dynamics simulations suggest that TSC2 Asn1643 and Rheb Tyr35 are key active site residues, while Rheb Arg15 and Asp65, previously proposed as catalytic residues, contribute to the TSC2-Rheb interface and indirectly aid catalysis. The TSC2 GAP domain is further stabilized by interactions with other TSC2 domains. We characterize TSC2 variants that partially affect TSC2 functionality and are associated with atypical symptoms in patients, suggesting that mutations in TSC1 and TSC2 might predispose to neurological and vascular disorders without fulfilling the clinical criteria for TSC.
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Affiliation(s)
- Patrick Hansmann
- Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany
| | - Anne Brückner
- Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany; Westfälische Wilhelms-Universität, Institute of Molecular Tumor Biology, Robert-Koch-Str. 43, 48149 Münster, Germany
| | - Stephan Kiontke
- Philipps-Universität Marburg, Faculty of Biology, Department of Plant Physiology and Photobiology, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Bianca Berkenfeld
- Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany
| | - Guiscard Seebohm
- University Hospital Münster, Institute for Genetics of Heart Diseases, Department of Cardiovascular Medicine, Robert-Koch-Str. 45, 48149 Münster, Germany
| | - Pascal Brouillard
- Université Catholique de Louvain, de Duve Institute, Human Molecular Genetics, Brussels, Belgium
| | - Miikka Vikkula
- Université Catholique de Louvain, de Duve Institute, Human Molecular Genetics, Brussels, Belgium; WELBIO (Walloon Excellence in Lifesciences and Biotechnology), de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Floor E Jansen
- Department of Child Neurology, Brain Center UMC Utrecht, Utrecht, the Netherlands
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Wytemaweg 80, 3015 CN Rotterdam, the Netherlands
| | - Andrea Oeckinghaus
- Westfälische Wilhelms-Universität, Institute of Molecular Tumor Biology, Robert-Koch-Str. 43, 48149 Münster, Germany
| | - Daniel Kümmel
- Westfälische Wilhelms-Universität, Institute of Biochemistry, Wilhelm Klemm-Str. 2, 48149 Münster, Germany.
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24
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Langemeyer L, Borchers AC, Herrmann E, Füllbrunn N, Han Y, Perz A, Auffarth K, Kümmel D, Ungermann C. A conserved and regulated mechanism drives endosomal Rab transition. eLife 2020; 9:56090. [PMID: 32391792 PMCID: PMC7239660 DOI: 10.7554/elife.56090] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/07/2020] [Indexed: 12/31/2022] Open
Abstract
Endosomes and lysosomes harbor Rab5 and Rab7 on their surface as key proteins involved in their identity, biogenesis, and fusion. Rab activation requires a guanine nucleotide exchange factor (GEF), which is Mon1-Ccz1 for Rab7. During endosome maturation, Rab5 is replaced by Rab7, though the underlying mechanism remains poorly understood. Here, we identify the molecular determinants for Rab conversion in vivo and in vitro, and reconstitute Rab7 activation with yeast and metazoan proteins. We show (i) that Mon1-Ccz1 is an effector of Rab5, (ii) that membrane-bound Rab5 is the key factor to directly promote Mon1-Ccz1 dependent Rab7 activation and Rab7-dependent membrane fusion, and (iii) that this process is regulated in yeast by the casein kinase Yck3, which phosphorylates Mon1 and blocks Rab5 binding. Our study thus uncovers the minimal feed-forward machinery of the endosomal Rab cascade and a novel regulatory mechanism controlling this pathway.
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Affiliation(s)
- Lars Langemeyer
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Ann-Christin Borchers
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Eric Herrmann
- University of Münster, Institute of Biochemistry, Münster, Germany
| | - Nadia Füllbrunn
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Yaping Han
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Angela Perz
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Kathrin Auffarth
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany
| | - Daniel Kümmel
- University of Münster, Institute of Biochemistry, Münster, Germany
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry section, Osnabrück, Germany.,University of Osnabrück, Center of Cellular Nanoanalytics (CellNanOs), Osnabrück, Germany
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25
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Dufner Almeida LG, Nanhoe S, Zonta A, Hosseinzadeh M, Kom-Gortat R, Elfferich P, Schaaf G, Kenter A, Kümmel D, Migone N, Povey S, Ekong R, Nellist M. Comparison of the functional and structural characteristics of rare TSC2 variants with clinical and genetic findings. Hum Mutat 2019; 41:759-773. [PMID: 31799751 PMCID: PMC7154745 DOI: 10.1002/humu.23963] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/31/2019] [Accepted: 11/27/2019] [Indexed: 01/09/2023]
Abstract
The TSC1 and TSC2 gene products interact to form the tuberous sclerosis complex (TSC), an important negative regulator of the mechanistic target of rapamycin complex 1 (TORC1). Inactivating mutations in TSC1 or TSC2 cause TSC, and the identification of a pathogenic TSC1 or TSC2 variant helps establish a diagnosis of TSC. However, it is not always clear whether TSC1 and TSC2 variants are inactivating. To determine whether TSC1 and TSC2 variants of uncertain clinical significance affect TSC complex function and cause TSC, in vitro assays of TORC1 activity can be employed. Here we combine genetic, functional, and structural approaches to try and classify a series of 15 TSC2 VUS. We investigated the effects of the variants on the formation of the TSC complex, on TORC1 activity and on TSC2 pre‐mRNA splicing. In 13 cases (87%), the functional data supported the hypothesis that the identified TSC2 variant caused TSC. Our results illustrate the benefits and limitations of functional testing for TSC.
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Affiliation(s)
- Luiz G Dufner Almeida
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Santoesha Nanhoe
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Andrea Zonta
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Mitra Hosseinzadeh
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Regina Kom-Gortat
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Peter Elfferich
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Gerben Schaaf
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Annegien Kenter
- Department of Developmental Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Daniel Kümmel
- Biochemistry and Structural Biology Section, Institute of Biochemistry, University of Munster, Munster, Germany
| | - Nicola Migone
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Sue Povey
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Rosemary Ekong
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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26
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Ungermann C, Kümmel D. Structure of membrane tethers and their role in fusion. Traffic 2019; 20:479-490. [DOI: 10.1111/tra.12655] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Christian Ungermann
- Biochemistry Section, Department of Biology/ChemistryUniversity of Osnabrück Osnabrück Germany
- Center for Cellular Nanoanalytics (CellNanOs)University of Osnabrück Osnabrück Germany
| | - Daniel Kümmel
- Biochemistry & Structural Biology Section, Institute of BiochemistryUniversity of Münster Münster Germany
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27
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28
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Gao J, Langemeyer L, Kümmel D, Reggiori F, Ungermann C. Molecular mechanism to target the endosomal Mon1-Ccz1 GEF complex to the pre-autophagosomal structure. eLife 2018; 7:31145. [PMID: 29446751 PMCID: PMC5841931 DOI: 10.7554/elife.31145] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 02/12/2018] [Indexed: 11/13/2022] Open
Abstract
During autophagy, a newly formed double membrane surrounds its cargo to generate the so-called autophagosome, which then fuses with a lysosome after closure. Previous work implicated that endosomal Rab7/Ypt7 associates to autophagosomes prior to their fusion with lysosomes. Here, we unravel how the Mon1-Ccz1 guanosine exchange factor (GEF) acting upstream of Ypt7 is specifically recruited to the pre-autophagosomal structure under starvation conditions. We find that Mon1-Ccz1 directly binds to Atg8, the yeast homolog of the members of the mammalian LC3 protein family. This requires at least one LIR motif in the Ccz1 C-terminus, which is essential for autophagy but not for endosomal transport. In agreement, only wild-type, but not LIR-mutated Mon1-Ccz1 promotes Atg8-dependent activation of Ypt7. Our data reveal how GEF targeting can specify the fate of a newly formed organelle and provide new insights into the regulation of autophagosome-lysosome fusion. Autophagy is a word derived from the Greek for “self-eating”. It describes a biological process in which a living cell breaks down its own material to release their chemical building blocks that can then be used to make new molecules. Autophagy is often triggered when a cell becomes damaged or when nutrients are in short supply. The hallmark of autophagy is the formation of structures called autophagosomes. These structures capture the cellular material, fuse with other compartments in the cell – namely endosomes in animals and vacuoles in yeast – and then deliver the material inside, ready to be broken down. For an autophagosome to fuse to an endosome or a vacuole, small proteins of the Rab protein family must be located on the surface of the autophagosome. Rab proteins are recruited to this surface by enzymes known as GEFs. However it remains unclear how most GEFs get to the surface of a compartment within the cell to begin with. The Mon1-Ccz1 complex is a GEF that occurs in yeast and animals, including fruit flies and humans. It is found on endosomes, and was recently shown to also localize to autophagosomes. Now, Gao et al. report that, in yeast, the Mon1-Ccz1 complex binds directly to a protein named Atg8. This protein is anchored on to the surface of autophagosomes, and is closely related to other proteins in animal cells. Gao et al. discovered that this specific GEF binds to Atg8 via at least one binding site on its Ccz1 component. This binding site is only needed for the GEF to localize to the autophagosomes; the Mon1-Czz1 complex can still bind to endosomes without it. Blocking the GEF from binding to Atg8 stopped the autophagosomes from fusing with vacuoles. These findings reveal how a GEF can be targeted to two distinct compartments in the cell: endosomes and autophagosomes. Further work is now needed to understand how this process is regulated by the availability of nutrients or damage to the cell, to ensure that autophagy is only triggered under the right conditions. Also, because cancer cells often rely on autophagy to survive, the molecules that regulate this process could represent possible targets for new anticancer drugs.
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Affiliation(s)
- Jieqiong Gao
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Lars Langemeyer
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Daniel Kümmel
- Structural Biology Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Fulvio Reggiori
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Christian Ungermann
- Biochemistry Section, Department of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
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29
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Langemeyer L, Perz A, Kümmel D, Ungermann C. A guanine nucleotide exchange factor (GEF) limits Rab GTPase-driven membrane fusion. J Biol Chem 2017; 293:731-739. [PMID: 29184002 DOI: 10.1074/jbc.m117.812941] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/14/2017] [Indexed: 11/06/2022] Open
Abstract
The identity of organelles in the endomembrane system of any eukaryotic cell critically depends on the correctly localized Rab GTPase, which binds effectors and thus promotes membrane remodeling or fusion. However, it is still unresolved which factors are required and therefore define the localization of the correct fusion machinery. Using SNARE-decorated proteoliposomes that cannot fuse on their own, we now demonstrate that full fusion activity can be achieved by just four soluble factors: a soluble SNARE (Vam7), a guanine nucleotide exchange factor (GEF, Mon1-Ccz1), a Rab-GDP dissociation inhibitor (GDI) complex (prenylated Ypt7-GDI), and a Rab effector complex (HOPS). Our findings reveal that the GEF Mon1-Ccz1 is necessary and sufficient for stabilizing prenylated Ypt7 on membranes. HOPS binding to Ypt7-GTP then drives SNARE-mediated fusion, which is fully GTP-dependent. We conclude that an entire fusion cascade can be controlled by a GEF.
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Affiliation(s)
| | | | - Daniel Kümmel
- Structural Biochemistry, Department of Biology/Chemistry, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
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30
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Hellinger R, Thell K, Vasileva M, Muhammad T, Gunasekera S, Kümmel D, Göransson U, Becker CW, Gruber CW. Chemical Proteomics for Target Discovery of Head-to-Tail Cyclized Mini-Proteins. Front Chem 2017; 5:73. [PMID: 29075625 PMCID: PMC5641551 DOI: 10.3389/fchem.2017.00073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/19/2017] [Indexed: 11/24/2022] Open
Abstract
Target deconvolution is one of the most challenging tasks in drug discovery, but a key step in drug development. In contrast to small molecules, there is a lack of validated and robust methodologies for target elucidation of peptides. In particular, it is difficult to apply these methods to cyclic and cysteine-stabilized peptides since they exhibit reduced amenability to chemical modification and affinity capture; however, such ribosomally synthesized and post-translationally modified peptide natural products are rich sources of promising drug candidates. For example, plant-derived circular peptides called cyclotides have recently attracted much attention due to their immunosuppressive effects and oral activity in the treatment of multiple sclerosis in mice, but their molecular target has hitherto not been reported. In this study, a chemical proteomics approach using photo-affinity crosslinking was developed to determine a target for the circular peptide [T20K]kalata B1. Using this prototypic nature-derived peptide enabled the identification of a possible functional modulation of 14-3-3 proteins. This biochemical interaction was validated via competition pull down assays as well as a cellular reporter assay indicating an effect on 14-3-3-dependent transcriptional activity. As proof of concept, the presented approach may be applicable for target elucidation of various cyclic peptides and mini-proteins, in particular cyclotides, which represent a promising class of molecules in drug discovery and development.
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Affiliation(s)
- Roland Hellinger
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Kathrin Thell
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Mina Vasileva
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Taj Muhammad
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Sunithi Gunasekera
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Daniel Kümmel
- School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Ulf Göransson
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Christian W Becker
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Vienna, Austria
| | - Christian W Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.,School of Biomedical Sciences, Faculty of Medicine, University of Queensland, St. Lucia, QLD, Australia
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31
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Krishnakumar SS, Li F, Coleman J, Schauder CM, Kümmel D, Pincet F, Rothman JE, Reinisch KM. Correction: Re-visiting the trans insertion model for complexin clamping. eLife 2017; 6. [PMID: 28880147 PMCID: PMC5589411 DOI: 10.7554/elife.31512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 08/24/2017] [Indexed: 11/13/2022] Open
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32
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Zech R, Kiontke S, Mueller U, Oeckinghaus A, Kümmel D. Structure of the Tuberous Sclerosis Complex 2 (TSC2) N Terminus Provides Insight into Complex Assembly and Tuberous Sclerosis Pathogenesis. J Biol Chem 2016; 291:20008-20. [PMID: 27493206 DOI: 10.1074/jbc.m116.732446] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Indexed: 12/12/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is caused by mutations in the TSC1 and TSC2 tumor suppressor genes. The gene products hamartin and tuberin form the TSC complex that acts as GTPase-activating protein for Rheb and negatively regulates the mammalian target of rapamycin complex 1 (mTORC1). Tuberin contains a RapGAP homology domain responsible for inactivation of Rheb, but functions of other protein domains remain elusive. Here we show that the TSC2 N terminus interacts with the TSC1 C terminus to mediate complex formation. The structure of the TSC2 N-terminal domain from Chaetomium thermophilum and a homology model of the human tuberin N terminus are presented. We characterize the molecular requirements for TSC1-TSC2 interactions and analyze pathological point mutations in tuberin. Many mutations are structural and produce improperly folded protein, explaining their effect in pathology, but we identify one point mutant that abrogates complex formation without affecting protein structure. We provide the first structural information on TSC2/tuberin with novel insight into the molecular function.
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Affiliation(s)
- Reinhard Zech
- From the Structural Biology Section, FB5 Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Stephan Kiontke
- From the Structural Biology Section, FB5 Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany
| | - Uwe Mueller
- Macromolecular Crystallography (BESSY-MX), Helmholtz-Zentrum Berlin für Materialien und Energie, 12489 Berlin, Germany, and
| | - Andrea Oeckinghaus
- Institute of Molecular Tumor Biology, Medical Faculty of the WWU Münster, 48149 Münster Germany
| | - Daniel Kümmel
- From the Structural Biology Section, FB5 Biology/Chemistry, University of Osnabrück, 49076 Osnabrück, Germany,
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33
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Krishnakumar SS, Li F, Coleman J, Schauder CM, Kümmel D, Pincet F, Rothman JE, Reinisch KM. Re-visiting the trans insertion model for complexin clamping. eLife 2015; 4. [PMID: 25831964 PMCID: PMC4384536 DOI: 10.7554/elife.04463] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 03/02/2015] [Indexed: 12/03/2022] Open
Abstract
We have previously proposed that complexin cross-links multiple pre-fusion SNARE complexes via a trans interaction to function as a clamp on SNARE-mediated neurotransmitter release. A recent NMR study was unable to detect the trans clamping interaction of complexin and therefore questioned the previous interpretation of the fluorescence resonance energy transfer and isothermal titration calorimetry data on which the trans clamping model was originally based. Here we present new biochemical data that underscore the validity of our previous interpretation and the continued relevancy of the trans insertion model for complexin clamping. DOI:http://dx.doi.org/10.7554/eLife.04463.001 Molecules called neurotransmitters are used to carry signals between neurons. The neurotransmitters in the first neuron are stored in small bubble-like structures called synaptic vesicles. When this neuron is ready to send a signal to a second neuron, the membrane that encloses the synaptic vesicle fuses with the cell membrane that surrounds the neuron. This involves SNARE proteins in the vesicle membrane interacting with similar proteins in the cell membrane to form a SNARE complex, which then proceeds to ‘zip’ the two membranes together. Other proteins are involved in the fusion process and the release of the neurotransmitters. For example, complexins bind to SNARE proteins during the formation of the SNARE complex in order to temporarily halt the fusion process. This ‘clamping’ interaction ensures that the neurotransmitters are released at the appropriate time. Researchers have proposed two different models of the clamping interaction. In the trans clamping model a region in the complexins called the accessory helix extends forward and clamps SNARE proteins that are present on the two membranes. An alternative model explains clamping in terms of electrostatic interactions between the accessory helix and the two membranes. These interactions are repulsive because the accessory helix and the membranes are all negatively charged. Now Krishnakumar, Li et al.—including some of the researchers who first proposed the trans clamping model—have used a variety of biochemical techniques to re-examine the clamping interaction. These experiments support the idea that the accessory helix binds to and clamps a SNARE protein, as suggested by the trans clamping model. The results of recent in vivo experiments on fruit flies have also provided support for the trans clamping model, although further work is need to compare the models in both in vitro and in vivo systems. DOI:http://dx.doi.org/10.7554/eLife.04463.002
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Affiliation(s)
- Shyam S Krishnakumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Feng Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Jeff Coleman
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Curtis M Schauder
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Daniel Kümmel
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,School of Biology/Chemistry, Univeristät Osnabrück, Osnabrück, Germany
| | - Frederic Pincet
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Laboratoire de Physique Statistique, UMR CNRS 8550 Associée aux Unive, Ecole Normale Supérieure, Paris, France
| | - James E Rothman
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Karin M Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, United States
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34
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Lürick A, Kuhlee A, Bröcker C, Kümmel D, Raunser S, Ungermann C. The Habc domain of the SNARE Vam3 interacts with the HOPS tethering complex to facilitate vacuole fusion. J Biol Chem 2015; 290:5405-13. [PMID: 25564619 DOI: 10.1074/jbc.m114.631465] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Membrane fusion at vacuoles requires a consecutive action of the HOPS tethering complex, which is recruited by the Rab GTPase Ypt7, and vacuolar SNAREs to drive membrane fusion. It is assumed that the Sec1/Munc18-like Vps33 within the HOPS complex is largely responsible for SNARE chaperoning. Here, we present direct evidence for HOPS binding to SNAREs and the Habc domain of the Vam3 SNARE protein, which may explain its function during fusion. We show that HOPS interacts strongly with the Vam3 Habc domain, assembled Q-SNAREs, and the R-SNARE Ykt6, but not the Q-SNARE Vti1 or the Vam3 SNARE domain. Electron microscopy combined with Nanogold labeling reveals that the binding sites for vacuolar SNAREs and the Habc domain are located in the large head of the HOPS complex, where Vps16 and Vps33 have been identified before. Competition experiments suggest that HOPS bound to the Habc domain can still interact with assembled Q-SNAREs, whereas Q-SNARE binding prevents recognition of the Habc domain. In agreement, membranes carrying Vam3ΔHabc fuse poorly unless an excess of HOPS is provided. These data suggest that the Habc domain of Vam3 facilitates the assembly of the HOPS/SNARE machinery at fusion sites and thus supports efficient membrane fusion.
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Affiliation(s)
- Anna Lürick
- From the Department of Biology/Chemistry, Biochemistry Section and
| | - Anne Kuhlee
- the Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Cornelia Bröcker
- From the Department of Biology/Chemistry, Biochemistry Section and
| | - Daniel Kümmel
- the Department of Biology/Chemistry, Structural Biology, University of Osnabrück, 49076 Osnabrück, Germany and
| | - Stefan Raunser
- the Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
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35
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Behrmann H, Lürick A, Kuhlee A, Balderhaar HK, Bröcker C, Kümmel D, Engelbrecht-Vandré S, Gohlke U, Raunser S, Heinemann U, Ungermann C. Structural identification of the Vps18 β-propeller reveals a critical role in the HOPS complex stability and function. J Biol Chem 2014; 289:33503-12. [PMID: 25324549 DOI: 10.1074/jbc.m114.602714] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Membrane fusion at the vacuole, the lysosome equivalent in yeast, requires the HOPS tethering complex, which is recruited by the Rab7 GTPase Ypt7. HOPS provides a template for the assembly of SNAREs and thus likely confers fusion at a distinct position on vacuoles. Five of the six subunits in HOPS have a similar domain prediction with strong similarity to COPII subunits and nuclear porins. Here, we show that Vps18 indeed has a seven-bladed β-propeller as its N-terminal domain by revealing its structure at 2.14 Å. The Vps18 N-terminal domain can interact with the N-terminal part of Vps11 and also binds to lipids. Although deletion of the Vps18 N-terminal domain does not preclude HOPS assembly, as revealed by negative stain electron microscopy, the complex is instable and cannot support membrane fusion in vitro. We thus conclude that the β-propeller of Vps18 is required for HOPS stability and function and that it can serve as a starting point for further structural analyses of the HOPS tethering complex.
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Affiliation(s)
- Heide Behrmann
- From the Max-Delbrück Center for Molecular Medicine, Macromolecular Structure and Interaction Group, Robert-Rössle-Strasse 10, 13125 Berlin, Germany, Freie Universität Berlin, Chemistry and Biochemistry Institute, Takustrasse 6, 14195 Berlin, Germany
| | - Anna Lürick
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Anne Kuhlee
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany, and
| | - Henning Kleine Balderhaar
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Cornelia Bröcker
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Daniel Kümmel
- Department of Biology/Chemistry, Structural Biology Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Siegfried Engelbrecht-Vandré
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| | - Ulrich Gohlke
- From the Max-Delbrück Center for Molecular Medicine, Macromolecular Structure and Interaction Group, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany, and
| | - Udo Heinemann
- From the Max-Delbrück Center for Molecular Medicine, Macromolecular Structure and Interaction Group, Robert-Rössle-Strasse 10, 13125 Berlin, Germany, Freie Universität Berlin, Chemistry and Biochemistry Institute, Takustrasse 6, 14195 Berlin, Germany,
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany,
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36
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Krishnakumar SS, Kümmel D, Jones SJ, Radoff DT, Reinisch KM, Rothman JE. Conformational dynamics of calcium-triggered activation of fusion by synaptotagmin. Biophys J 2014; 105:2507-16. [PMID: 24314081 DOI: 10.1016/j.bpj.2013.10.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 10/11/2013] [Accepted: 10/23/2013] [Indexed: 01/03/2023] Open
Abstract
Synaptotagmin triggers rapid exocytosis of neurotransmitters from synaptic vesicles in response to Calcium (Ca(2+)) ions. Here, we use a novel Nanodisc-based system, designed to be a soluble mimetic of the clamped synaptic vesicle-bilayer junction, combined with fluorescence resonance energy transfer (FRET) spectroscopy to monitor the structural relationships among SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptor), Synaptotagmin C2 domains, and the lipid bilayer in real time during the Ca(2+)-activation process. We report that Synaptotagmin remains rigidly fixed on the partially assembled SNARE complex with no detectable internal rearrangement of its C2 domains, even as it rapidly inserts into the bilayer. We hypothesize that this straightforward, one-step physical mechanism could explain how this Ca(2+)- sensor rapidly activates neurotransmitter release from the clamped state.
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Affiliation(s)
- Shyam S Krishnakumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut.
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37
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Kümmel D, Ungermann C. Principles of membrane tethering and fusion in endosome and lysosome biogenesis. Curr Opin Cell Biol 2014; 29:61-6. [PMID: 24813801 DOI: 10.1016/j.ceb.2014.04.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/15/2014] [Accepted: 04/23/2014] [Indexed: 11/29/2022]
Abstract
Endosomes and lysosomes receive cargo via vesicular carriers that arrive along multiple trafficking routes. On both organelles, tethering proteins have been identified that interact specifically with Rab5 on endosomes and Rab7 on late endosomes/lysosomes and that facilitate the SNARE-driven membrane fusion. Even though the structure and stoichiometry of the involved proteins and protein complexes differ strongly, they may operate by similar principles. Within this review, we will provide insights into their common functions and discuss the open questions in the field.
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Affiliation(s)
- Daniel Kümmel
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry Section, Barbarastrasse 13, Osnabrück 49076, Germany.
| | - Christian Ungermann
- University of Osnabrück, Department of Biology/Chemistry, Biochemistry Section, Barbarastrasse 13, Osnabrück 49076, Germany.
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38
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Li F, Kümmel D, Coleman J, Reinisch KM, Rothman JE, Pincet F. A half-zippered SNARE complex represents a functional intermediate in membrane fusion. J Am Chem Soc 2014; 136:3456-64. [PMID: 24533674 PMCID: PMC3985920 DOI: 10.1021/ja410690m] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
SNARE
(soluble N-ethylmaleimide-sensitive factor
attachment protein receptor) proteins mediate fusion by pulling biological
membranes together via a zippering mechanism. Recent biophysical studies
have shown that t- and v-SNAREs can assemble in multiple stages from
the N-termini toward the C-termini. Here we show that functionally,
membrane fusion requires a sequential, two-step folding pathway and
assign specific and distinct functions for each step. First, the N-terminal
domain (NTD) of the v-SNARE docks to the t-SNARE, which leads to a
conformational rearrangement into an activated half-zippered SNARE
complex. This partially assembled SNARE complex locks the C-terminal
(CTD) portion of the t-SNARE into the same structure as in the postfusion
4-helix bundle, thereby creating the binding site for the CTD of the
v-SNARE and enabling fusion. Then zippering of the remaining CTD,
the membrane-proximal linker (LD), and transmembrane (TMD) domains
is required and sufficient to trigger fusion. This intrinsic property
of the SNAREs fits well with the action of physiologically vital regulators
such as complexin. We also report that NTD assembly is the rate-limiting
step. Our findings provide a refined framework for delineating the
molecular mechanism of SNARE-mediated membrane fusion and action of
regulatory proteins.
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Affiliation(s)
- Feng Li
- Department of Cell Biology, School of Medicine, Yale University , 333 Cedar Street, New Haven, Connecticut 06520, United States
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39
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Shen D, Yuan H, Hutagalung A, Verma A, Kümmel D, Wu X, Reinisch K, McNew JA, Novick P. The synaptobrevin homologue Snc2p recruits the exocyst to secretory vesicles by binding to Sec6p. ACTA ACUST UNITED AC 2013; 202:509-26. [PMID: 23897890 PMCID: PMC3734085 DOI: 10.1083/jcb.201211148] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The exocyst is recruited to secretory vesicles by the combinatorial signals of Sec4-GTP and the Snc proteins to confer both specificity and directionality to vesicular traffic. A screen for mutations that affect the recruitment of the exocyst to secretory vesicles identified genes encoding clathrin and proteins that associate or colocalize with clathrin at sites of endocytosis. However, no significant colocalization of the exocyst with clathrin was seen, arguing against a direct role in exocyst recruitment. Rather, these components are needed to recycle the exocytic vesicle SNAREs Snc1p and Snc2p from the plasma membrane into new secretory vesicles where they act to recruit the exocyst. We observe a direct interaction between the exocyst subunit Sec6p and the latter half of the SNARE motif of Snc2p. An snc2 mutation that specifically disrupts this interaction led to exocyst mislocalization and a block in exocytosis in vivo without affecting liposome fusion in vitro. Overexpression of Sec4p partially suppressed the exocyst localization defects of mutations in clathrin and clathrin-associated components. We propose that the exocyst is recruited to secretory vesicles by the combinatorial signals of Sec4-GTP and the Snc proteins. This could help to confer both specificity and directionality to vesicular traffic.
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Affiliation(s)
- David Shen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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40
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Jackson LP, Kümmel D, Reinisch KM, Owen DJ. Structures and mechanisms of vesicle coat components and multisubunit tethering complexes. Curr Opin Cell Biol 2012; 24:475-83. [PMID: 22728063 DOI: 10.1016/j.ceb.2012.05.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 05/23/2012] [Indexed: 11/17/2022]
Abstract
Eukaryotic cells face a logistical challenge in ensuring prompt and precise delivery of vesicular cargo to specific organelles within the cell. Coat protein complexes select cargo and initiate vesicle formation, while multisubunit tethering complexes participate in the delivery of vesicles to target membranes. Understanding these macromolecular assemblies has greatly benefited from their structural characterization. Recent structural data highlight principles in coat recruitment and uncoating in both the endocytic and retrograde pathways, and studies on the architecture of tethering complexes provide a framework for how they might link vesicles to the respective acceptor compartments and the fusion machinery.
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Affiliation(s)
- Lauren P Jackson
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, Cambridge CB2 0XY, UK.
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41
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Abstract
The function of the Golgi has long been recognized to critically depend on vesicular transport from, to, and within its cisternae, involving constant membrane fission and fusion. These processes are mediated by Arf GTPases and coat proteins, and Rabs, tethers and SNARE proteins, respectively. In this article, we describe structural studies of Golgi coats and tethers and their interactions with SNAREs and GTPases as well as insights regarding membrane traffic processes that these have provided.
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Affiliation(s)
- Daniel Kümmel
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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42
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Shi L, Kümmel D, Coleman J, Melia TJ, Giraudo CG. Dual roles of Munc18-1 rely on distinct binding modes of the central cavity with Stx1A and SNARE complex. Mol Biol Cell 2011; 22:4150-60. [PMID: 21900493 PMCID: PMC3204075 DOI: 10.1091/mbc.e11-02-0150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Sec1/Munc18 proteins play a fundamental role in multiple steps of intracellular membrane trafficking. Dual functions have been attributed to Munc18-1: it can act as a chaperone when it interacts with monomeric syntaxin 1A, and it can activate soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) for membrane fusion when it binds to SNARE complexes. Although both modes of binding involve the central cavity of Munc18-1, their precise molecular mechanisms of action are not fully understood. In this paper, we describe a novel Munc18-1 mutant in the central cavity that showed a reduced interaction with syntaxin 1A and impaired chaperone function, but still bound to assembled SNARE complexes and promoted liposome fusion and secretion in neuroendocrine cells. Soluble syntaxin 1A H3 domain partially blocks Munc18-1 activation of liposome fusion by occupying the Munc18-1 central cavity. Our findings lead us to propose a transition model between the two distinct binding modes by which Munc18 can control and assist in SNARE-complex assembly during neurotransmitter release.
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Affiliation(s)
- Lei Shi
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06520, USA
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43
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Krishnakumar SS, Radoff DT, Kümmel D, Giraudo CG, Li F, Khandan L, Baguley SW, Coleman J, Reinisch KM, Pincet F, Rothman JE. A conformational switch in complexin is required for synaptotagmin to trigger synaptic fusion. Nat Struct Mol Biol 2011; 18:934-40. [PMID: 21785412 DOI: 10.1038/nsmb.2103] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/19/2011] [Indexed: 11/09/2022]
Abstract
The crystal structure of complexin bound to a prefusion SNAREpin mimetic shows that the accessory helix extends away from the SNAREpin in an 'open' conformation, binding another SNAREpin and inhibiting its assembly, to clamp fusion. In contrast, the accessory helix in the postfusion complex parallels the SNARE complex in a 'closed' conformation. Here we use targeted mutations, FRET spectroscopy and a functional assay that reconstitutes Ca(2+)-triggered exocytosis to show that the conformational switch from open to closed in complexin is needed for synaptotagmin-Ca(2+) to trigger fusion. Triggering fusion requires the zippering of three crucial aspartate residues in the switch region (residues 64-68) of v-SNARE. Conformational switching in complexin is integral to clamp release and is probably triggered when its accessory helix is released from its trans-binding to the neighboring SNAREpin, allowing the v-SNARE to complete zippering and open a fusion pore.
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Affiliation(s)
- Shyam S Krishnakumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
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44
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Kümmel D, Walter J, Heck M, Heinemann U, Veit M. Characterization of the self-palmitoylation activity of the transport protein particle component Bet3. Cell Mol Life Sci 2010; 67:2653-64. [PMID: 20372964 DOI: 10.1007/s00018-010-0358-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/15/2010] [Accepted: 03/16/2010] [Indexed: 10/19/2022]
Abstract
Bet3, a transport protein particle component involved in vesicular trafficking, contains a hydrophobic tunnel occupied by a fatty acid linked to cysteine 68. We reported that Bet3 has a unique self-palmitoylating activity. Here we show that mutation of arginine 67 reduced self-palmitoylation of Bet3, but the effect was compensated by increasing the pH. Thus, arginine helps to deprotonate cysteine such that it could function as a nucleophile in the acylation reaction which is supported by the structural analysis of non-acylated Bet3. Using fluorescence spectroscopy we show that long-chain acyl-CoAs bind with micromolar affinity to Bet3, whereas shorter-chain acyl-CoAs do not interact. Mutants with a deleted acylation site or a blocked tunnel bind to Pal-CoA, only the latter with slightly reduced affinity. Bet3 contains three binding sites for Pal-CoA, but their number was reduced to two in the mutant with an obstructed tunnel, indicating that Bet3 contains binding sites on its surface.
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Affiliation(s)
- Daniel Kümmel
- Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, Berlin, Germany
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45
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Abstract
The golgin family gives identity and structure to the Golgi apparatus and is part of a complex protein network at the Golgi membrane. The golgin p115 is targeted by the GTPase Rab1a, contains a large globular head region and a long region of coiled-coil which forms an extended rod-like structure. p115 serves as vesicle tethering factor and plays an important role at different steps of vesicular transport. Here we present the 2.2 Å-resolution X-ray structure of the globular head region of p115. The structure exhibits an armadillo fold that is decorated by elongated loops and carries a C-terminal non-canonical repeat. This terminal repeat folds into the armadillo superhelical groove and allows homodimeric association with important implications for p115 mediated multiple protein interactions and tethering.
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Affiliation(s)
- Harald Striegl
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Yvette Roske
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Daniel Kümmel
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Udo Heinemann
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
- * E-mail:
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46
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Kümmel D, Heinemann U. Diversity in structure and function of tethering complexes: evidence for different mechanisms in vesicular transport regulation. Curr Protein Pept Sci 2008; 9:197-209. [PMID: 18393888 DOI: 10.2174/138920308783955252] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The term 'tethering factor' has been coined for a heterogeneous group of proteins that all are required for protein trafficking prior to vesicle docking and SNARE-mediated membrane fusion. Two groups of tethering factors can be distinguished, long coiled-coil proteins and multi-subunit complexes. To date, eight such protein complexes have been identified in yeast, and they are required for different trafficking steps. Homologous complexes are found in all eukaryotic organisms, but conservation seems to be less strict than for other components of the trafficking machinery. In fact, for most proposed multi-subunit tethers their ability to actually bridge two membranes remains to be shown. Here we discuss recent progress in the structural and functional characterization of tethering complexes and present the emerging view that the different complexes are quite diverse in their structure and the molecular mechanisms underlying their function. TRAPP and the exocyst are the structurally best characterized tethering complexes. Their comparison fails to reveal any similarity on a struc nottural level. Furthermore, the interactions with regulatory Rab GTPases vary, with TRAPP acting as a nucleotide exchange factor and the exocyst being an effector. Considering these differences among the tethering complexes as well as between their yeast and mammalian orthologs which is apparent from recent studies, we suggest that tethering complexes do not mediate a strictly conserved process in vesicular transport but are diverse regulators acting after vesicle budding and prior to membrane fusion.
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Affiliation(s)
- D Kümmel
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, Berlin, Germany
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Abstract
A vector system is presented that allows generation of E. coli co-expression clones by a standardized, robust cloning procedure. The number of co-expressed proteins is not limited. Five ‘pQLink’ vectors for expression of His-tag and GST-tag fusion proteins as well as untagged proteins and for cloning by restriction enzymes or Gateway cloning were generated. The vectors allow proteins to be expressed individually; to achieve co-expression, two pQLink plasmids are combined by ligation-independent cloning. pQLink co-expression plasmids can accept an unrestricted number of genes. As an example, the co-expression of a heterotetrameric human transport protein particle (TRAPP) complex from a single plasmid, its isolation and analysis of its stoichiometry are shown. pQLink clones can be used directly for pull-down experiments if the proteins are expressed with different tags. We demonstrate pull-down experiments of human valosin-containing protein (VCP) with fragments of the autocrine motility factor receptor (AMFR). The cloning method avoids PCR or gel isolation of restriction fragments, and a single resistance marker and origin of replication are used, allowing over-expression of rare tRNAs from a second plasmid. It is expected that applications are not restricted to bacteria, but could include co-expression in other hosts such as Bacluovirus/insect cells.
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Affiliation(s)
- Christoph Scheich
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestr. 63-73, 14195 Berlin, Germany, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany and Free University of Berlin, Institute of Chemistry and Biochemistry, Takustraße 6, 14195 Berlin, Germany
| | - Daniel Kümmel
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestr. 63-73, 14195 Berlin, Germany, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany and Free University of Berlin, Institute of Chemistry and Biochemistry, Takustraße 6, 14195 Berlin, Germany
| | - Dimitri Soumailakakis
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestr. 63-73, 14195 Berlin, Germany, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany and Free University of Berlin, Institute of Chemistry and Biochemistry, Takustraße 6, 14195 Berlin, Germany
| | - Udo Heinemann
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestr. 63-73, 14195 Berlin, Germany, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany and Free University of Berlin, Institute of Chemistry and Biochemistry, Takustraße 6, 14195 Berlin, Germany
| | - Konrad Büssow
- Max Planck Institute for Molecular Genetics, Department of Vertebrate Genomics, Ihnestr. 63-73, 14195 Berlin, Germany, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany and Free University of Berlin, Institute of Chemistry and Biochemistry, Takustraße 6, 14195 Berlin, Germany
- *To whom correspondence should be addressed. +49 30 9406 2983+49 30 9406 2925
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Kümmel D, Heinemann U, Veit M. Unique self-palmitoylation activity of the transport protein particle component Bet3: a mechanism required for protein stability. Proc Natl Acad Sci U S A 2006; 103:12701-6. [PMID: 16908848 PMCID: PMC1562543 DOI: 10.1073/pnas.0603513103] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Indexed: 11/18/2022] Open
Abstract
Bet3 is a component of the transport protein particle complex involved in vesicular trafficking to and through the Golgi complex. X-ray structural analysis of human and mouse Bet3 revealed a hydrophobic tunnel inside the protein, which is occupied by a fatty acid linked to cysteine-68. We show here that Bet3 has strong self-palmitoylating activity. Incubation of purified Bet3 with [3H]palmitoyl-CoA (Pal-CoA) leads to a rapid and stoichiometric attachment of fatty acids to cysteine-68. Bet3 has an intrinsic affinity for Pal-CoA, and the palmitoylation reaction occurs at physiological pH values and Pal-CoA concentrations. Moreover, Bet3 is also efficiently palmitoylated at cysteine-68 inside vertebrate cells. Palmitoylation can occur late after Bet3 synthesis, but once the fatty acids are bound they are not removed, not even by disassembly of the Golgi complex. Narrowing the hydrophobic tunnel by exchange of alanine-82 with bulkier amino acids inhibits palmitoylation, both in vitro and inside cells, indicating that the fatty acid must insert into the tunnel for stable attachment. Finally, we show that palmitoylation of Bet3 plays a structural role. CD spectroscopy reveals that chemically deacylated Bet3 has a reduced melting temperature. As a consequence of its structural defect nonacylated Bet3 does not bind to TPC6, a further subunit of the transport protein particle complex, and is degraded inside cells.
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Affiliation(s)
- Daniel Kümmel
- *Max Delbrück Center for Molecular Medicine, Robert-Rössle Strasse 10, 13125 Berlin, Germany
- Institute for Chemistry and Biochemistry, Free University, Takustrasse 6, 14195 Berlin, Germany; and
| | - Udo Heinemann
- *Max Delbrück Center for Molecular Medicine, Robert-Rössle Strasse 10, 13125 Berlin, Germany
- Institute for Chemistry and Biochemistry, Free University, Takustrasse 6, 14195 Berlin, Germany; and
| | - Michael Veit
- Department of Immunology and Molecular Biology, Free University, Philippstrasse 13, 10115 Berlin, Germany
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Kümmel D, Müller JJ, Roske Y, Henke N, Heinemann U. Structure of the Bet3-Tpc6B core of TRAPP: two Tpc6 paralogs form trimeric complexes with Bet3 and Mum2. J Mol Biol 2006; 361:22-32. [PMID: 16828797 DOI: 10.1016/j.jmb.2006.06.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 06/02/2006] [Accepted: 06/06/2006] [Indexed: 11/29/2022]
Abstract
The transport protein particle (TRAPP) complexes are involved in the tethering process at different trafficking steps of vesicle transport. We here present the crystal structure of a human Bet3-Tpc6B heterodimer, which represents a core sub-complex in the assembly of TRAPP. We describe a conserved patch of Tpc6 with uncharged pockets, forming a putative interaction interface for an anchoring moiety at the Golgi. The structural and functional comparison of the two paralogs Tpc6A and Tpc6B, only found in some organisms, indicates redundancy and added complexity of TRAPP architecture and function. Both iso-complexes, Bet3-Tpc6A and Bet3-Tpc6B, are able to recruit Mum2, a further TRAPP subunit, and we identify the alpha1-alpha2 loop regions as a binding site for Mum2. Our study reveals similar stability of the iso-complexes and similar expression patterns of the tpc6 variants in different mouse organs. These findings raise the possibility that the Tpc6 paralogs might contribute to the formation of two distinct TRAPP complexes that differ in function.
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Affiliation(s)
- Daniel Kümmel
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
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Kümmel D, Müller JJ, Roske Y, Misselwitz R, Büssow K, Heinemann U. The structure of the TRAPP subunit TPC6 suggests a model for a TRAPP subcomplex. EMBO Rep 2006; 6:787-93. [PMID: 16025134 PMCID: PMC1369139 DOI: 10.1038/sj.embor.7400463] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 05/17/2005] [Accepted: 05/25/2005] [Indexed: 11/08/2022] Open
Abstract
The TRAPP (transport protein particle) complexes are tethering complexes that have an important role at the different steps of vesicle transport. Recently, the crystal structures of the TRAPP subunits SEDL and BET3 have been determined, and we present here the 1.7 Angstroms crystal structure of human TPC6, a third TRAPP subunit. The protein adopts an alpha/beta-plait topology and forms a dimer. In spite of low sequence similarity, the structure of TPC6 strikingly resembles that of BET3. The similarity is especially prominent at the dimerization interfaces of the proteins. This suggests heterodimerization of TPC6 and BET3, which is shown by in vitro and in vivo association studies. Together with TPC5, another TRAPP subunit, TPC6 and BET3 are supposed to constitute a family of paralogous proteins with closely similar three-dimensional structures but little sequence similarity among its members.
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Affiliation(s)
- Daniel Kümmel
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany
- Chemistry Institute, Free University, Takustrasse 6, 14195 Berlin, Germany
| | - Jürgen J Müller
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany
| | - Yvette Roske
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
| | - Rolf Misselwitz
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany
| | - Konrad Büssow
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany
| | - Udo Heinemann
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13092 Berlin, Germany
- Chemistry Institute, Free University, Takustrasse 6, 14195 Berlin, Germany
- Tel: +49 30 9406 3420; Fax: +49 30 9406 2548; E-mail:
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