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Le LTM, Drakulic S, Nyengaard JR, Golas MM, Sander B. Structural Organization of Human Full-Length PAR3 and the aPKC-PAR6 Complex. Mol Biotechnol 2022; 64:1319-1327. [PMID: 35610404 PMCID: PMC9573856 DOI: 10.1007/s12033-022-00504-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 04/29/2022] [Indexed: 11/24/2022]
Abstract
The tripartite partition defect (PAR) polarity complex, which includes the proteins PAR3, atypical protein kinase C (aPKC), and PAR6, is a major regulator of cellular polarity. It is highly conserved and expressed in various tissues. Its largest component, PAR3, controls protein–protein interactions of the PAR complex with a variety of interaction partners, and PAR3 self-association is critical for the formation of filament-like structures. However, little is known about the structure of the PAR complex. Here, we purified non-filamentous PAR3 and the aPKC–PAR6 complex and characterized them by single-particle electron microscopy (EM). We expressed and purified an oligomerization-deficient form of PAR3, PAR3V13D,D70K, and the active aPKC–PAR6 dimer. For PAR3, engineering at two positions is sufficient to form stable single particles with a maximum dimension of 20 nm. aPKC–PAR6 forms a complex with a maximum dimension of 13.5 nm that contains single copies of aPKC. Thus, the data present a basis for further high-resolution studies of PAR proteins and PAR complex formation.
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Affiliation(s)
- Le T M Le
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Pathology, Aarhus University Hospital, Aarhus, Denmark
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Srdja Drakulic
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jens R Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm Meyers Allé 3, Building 1233/1234, 8000, Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Human Genetics, Faculty of Medicine, University of Augsburg, Stenglinstrasse 2, 86156, Augsburg, Germany
| | - Bjoern Sander
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm Meyers Allé 3, Building 1233/1234, 8000, Aarhus C, Denmark.
- Institute of Pathology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Golas MM, Jayaprakash S, Le LTM, Zhao Z, Heras Huertas V, Jensen IS, Yuan J, Sander B. Modulating the Expression Strength of the Baculovirus/Insect Cell Expression System: A Toolbox Applied to the Human Tumor Suppressor SMARCB1/SNF5. Mol Biotechnol 2018; 60:820-832. [DOI: 10.1007/s12033-018-0107-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Le LTM, Nyengaard JR, Golas MM, Sander B. Vectors for Expression of Signal Peptide-Dependent Proteins in Baculovirus/Insect Cell Systems and Their Application to Expression and Purification of the High-Affinity Immunoglobulin Gamma Fc Receptor I in Complex with Its Gamma Chain. Mol Biotechnol 2018; 60:31-40. [PMID: 29143175 DOI: 10.1007/s12033-017-0041-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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] [Indexed: 12/29/2022]
Abstract
Integral membrane proteins play a central role in various cellular functions and are important therapeutic targets. However, technical challenges in the overexpression and purification of membrane proteins often represent a limiting factor for biochemical and structural studies. Here, we constructed a set of vectors, derivatives of MultiBac vectors that can be used to express proteins with a cleavable N-terminal signal peptide in insect cells. We propose these vectors for expression of type I membrane proteins and other secretory pathway proteins that require the signal recognition particle for translocation to the endoplasmic reticulum (ER). The vectors code for N-terminal and C-terminal affinity tags including 3 × FLAG and Twin-Strep, which represent tags compatible with efficient translocation to the ER as well as with purification under mild conditions that preserve protein structure and function. As a model, we used our system to express and purify the engineered high-affinity immunoglobulin gamma Fc receptor I (CD64) in complex with its gamma subunit (γ-chain). We demonstrate that CD64 expressed in complex with the γ-chain is functional in immunoglobulin G (IgG) binding. The sedimentation of CD64 in complex with IgG suggests individual CD64/IgG complexes in addition to formation of high-molecular weight complexes. In summary, our vectors can be used as a tool for expression of membrane proteins, other secretory pathway proteins and their protein complexes.
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Affiliation(s)
- Le T M Le
- Stereology and EM Laboratory, Department of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Jens R Nyengaard
- Stereology and EM Laboratory, Department of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark
- Core Center for Molecular Morphology, Department of Clinical Medicine, Aarhus University Hospital, 8000, Aarhus C, Denmark
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, 8000, Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233/1234, 8000, Aarhus C, Denmark
- Department of Human Genetics, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Bjoern Sander
- Stereology and EM Laboratory, Department of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark.
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, 8000, Aarhus C, Denmark.
- Institute of Pathology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Inui K, Zhao Z, Yuan J, Jayaprakash S, Le LTM, Drakulic S, Sander B, Golas MM. Stepwise assembly of functional C-terminal REST/NRSF transcriptional repressor complexes as a drug target. Protein Sci 2017; 26:997-1011. [PMID: 28218430 DOI: 10.1002/pro.3142] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [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: 10/31/2016] [Revised: 02/05/2017] [Accepted: 02/10/2017] [Indexed: 01/15/2023]
Abstract
In human cells, thousands of predominantly neuronal genes are regulated by the repressor element 1 (RE1)-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF). REST/NRSF represses transcription of these genes in stem cells and non-neuronal cells by tethering corepressor complexes. Aberrant REST/NRSF expression and intracellular localization are associated with cancer and neurodegeneration in humans. To date, detailed molecular analyses of REST/NRSF and its C-terminal repressor complex have been hampered largely by the lack of sufficient amounts of purified REST/NRSF and its complexes. Therefore, the aim of this study was to express and purify human REST/NRSF and its C-terminal interactors in a baculovirus multiprotein expression system as individual proteins and coexpressed complexes. All proteins were enriched in the nucleus, and REST/NRSF was isolated as a slower migrating form, characteristic of nuclear REST/NRSF in mammalian cells. Both REST/NRSF alone and its C-terminal repressor complex were functionally active in histone deacetylation and histone demethylation and bound to RE1/neuron-restrictive silencer element (NRSE) sites. Additionally, the mechanisms of inhibition of the small-molecule drugs 4SC-202 and SP2509 were analyzed. These drugs interfered with the viability of medulloblastoma cells, where REST/NRSF has been implicated in cancer pathogenesis. Thus, a resource for molecular REST/NRSF studies and drug development has been established.
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Affiliation(s)
- Ken Inui
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Zongpei Zhao
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Juan Yuan
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | | | - Le T M Le
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Srdja Drakulic
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Bjoern Sander
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.,Institute of Human Genetics, Hannover Medical School, D-30625 Hannover, Germany
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Kjaer TR, Le LTM, Pedersen JS, Sander B, Golas MM, Jensenius JC, Andersen GR, Thiel S. Structural insights into the initiating complex of the lectin pathway of complement activation. Structure 2015; 23:342-51. [PMID: 25579818 DOI: 10.1016/j.str.2014.10.024] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/18/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
Abstract
The proteolytic cascade of the complement system is initiated when pattern-recognition molecules (PRMs) bind to ligands, resulting in the activation of associated proteases. In the lectin pathway of complement, the complex of mannan-binding lectin (MBL) and MBL-associated serine protease-1 (MASP-1) initiates the pathway by activating a second protease, MASP-2. Here we present a structural study of a PRM/MASP complex and derive the overall architecture of the 450 kDa MBL/MASP-1 complex using small-angle X-ray scattering and electron microscopy. The serine protease (SP) domains from the zymogen MASP-1 dimer protrude from the cone-like MBL tetramer and are separated by at least 20 nm. This suggests that intracomplex activation within a single MASP-1 dimer is unlikely and instead supports intercomplex activation, whereby the MASP SP domains are accessible to nearby PRM-bound MASPs. This activation mechanism differs fundamentally from the intracomplex initiation models previously proposed for both the lectin and the classical pathway.
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Affiliation(s)
- Troels R Kjaer
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Le T M Le
- Department of Clinical Medicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Bjoern Sander
- Department of Clinical Medicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark; Center for Stochastic Geometry and Advanced Bioimaging (CSGB), Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark; Center for Stochastic Geometry and Advanced Bioimaging (CSGB), Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Jens Christian Jensenius
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark.
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