1
|
Wang YJ, Di XJ, Mu TW. Quantitative interactome proteomics identifies a proteostasis network for GABA A receptors. J Biol Chem 2022; 298:102423. [PMID: 36030824 PMCID: PMC9493394 DOI: 10.1016/j.jbc.2022.102423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
Gamma-aminobutyric acid type A (GABAA) receptors are the primary inhibitory neurotransmitter-gated ion channels in the mammalian central nervous system. Maintenance of GABAA receptor protein homeostasis (proteostasis) in cells utilizing its interacting proteins is essential for the function of GABAA receptors. However, how the proteostasis network orchestrates GABAA receptor biogenesis in the endoplasmic reticulum is not well understood. Here, we employed a proteomics-based approach to systematically identify the interactomes of GABAA receptors. We carried out a quantitative immunoprecipitation-tandem mass spectrometry analysis utilizing stable isotope labeling by amino acids in cell culture. Furthermore, we performed comparative proteomics by using both WT α1 subunit and a misfolding-prone α1 subunit carrying the A322D variant as the bait proteins. We identified 125 interactors for WT α1-containing receptors, 105 proteins for α1(A322D)-containing receptors, and 54 overlapping proteins within these two interactomes. Our bioinformatics analysis identified potential GABAA receptor proteostasis network components, including chaperones, folding enzymes, trafficking factors, and degradation factors, and we assembled a model of their potential involvement in the cellular folding, degradation, and trafficking pathways for GABAA receptors. In addition, we verified endogenous interactions between α1 subunits and selected interactors by using coimmunoprecipitation in mouse brain homogenates. Moreover, we showed that TRIM21 (tripartite motif containing-21), an E3 ubiquitin ligase, positively regulated the degradation of misfolding-prone α1(A322D) subunits selectively. This study paves the way for understanding the molecular mechanisms as well as fine-tuning of GABAA receptor proteostasis to ameliorate related neurological diseases such as epilepsy.
Collapse
Affiliation(s)
- Ya-Juan Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA; Center for Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
| | - Xiao-Jing Di
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
| |
Collapse
|
2
|
Analysis of rainbow trout TCRαβ/CD3 complex: An in-silico modeling approach. Mol Immunol 2022; 144:35-43. [DOI: 10.1016/j.molimm.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/18/2022]
|
3
|
Ch'ng ACW, Lam P, Alassiri M, Lim TS. Application of phage display for T-cell receptor discovery. Biotechnol Adv 2021; 54:107870. [PMID: 34801662 DOI: 10.1016/j.biotechadv.2021.107870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/23/2021] [Accepted: 11/15/2021] [Indexed: 12/13/2022]
Abstract
The immune system is tasked to keep our body unharmed and healthy. In the immune system, B- and T-lymphocytes are the two main components working together to stop and eliminate invading threats like virus particles, bacteria, fungi and parasite from attacking our healthy cells. The function of antibodies is relatively more direct in target recognition as compared to T-cell receptors (TCR) which recognizes antigenic peptides being presented on the major histocompatibility complex (MHC). Although phage display has been widely applied for antibody presentation, this is the opposite in the case of TCR. The cell surface TCR is a relatively large and complex molecule, making presentation on phage surfaces challenging. Even so, recombinant versions and modifications have been introduced to allow the growing development of TCR in phage display. In addition, the increasing application of TCR for immunotherapy has made it an important binding motif to be developed by phage display. This review will emphasize on the application of phage display for TCR discovery as well as the engineering aspect of TCR for improved characteristics.
Collapse
Affiliation(s)
- Angela Chiew Wen Ch'ng
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Paula Lam
- CellVec Private Limited, 118518, Singapore; National University of Singapore, Department of Physiology, 117597, Singapore; Duke-NUS Graduate Medical School, Cancer and Stem Cells Biology Program, 169857, Singapore
| | - Mohammed Alassiri
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia
| | - Theam Soon Lim
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 Penang, Malaysia; Analytical Biochemistry Research Centre, Universiti Sains Malaysia, 11800 Penang, Malaysia.
| |
Collapse
|
4
|
Liu X, Yu J, Xu L, Umphred-Wilson K, Peng F, Ding Y, Barton BM, Lv X, Zhao MY, Sun S, Hong Y, Qi L, Adoro S, Chen X. Notch-induced endoplasmic reticulum-associated degradation governs mouse thymocyte β-selection. eLife 2021; 10:e69975. [PMID: 34240701 PMCID: PMC8315795 DOI: 10.7554/elife.69975] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/05/2021] [Indexed: 11/13/2022] Open
Abstract
Signals from the pre-T cell receptor and Notch coordinately instruct β-selection of CD4-CD8-double negative (DN) thymocytes to generate αβ T cells in the thymus. However, how these signals ensure a high-fidelity proteome and safeguard the clonal diversification of the pre-selection TCR repertoire given the considerable translational activity imposed by β-selection is largely unknown. Here, we identify the endoplasmic reticulum (ER)-associated degradation (ERAD) machinery as a critical proteostasis checkpoint during β-selection. Expression of the SEL1L-HRD1 complex, the most conserved branch of ERAD, is directly regulated by the transcriptional activity of the Notch intracellular domain. Deletion of Sel1l impaired DN3 to DN4 thymocyte transition and severely impaired mouse αβ T cell development. Mechanistically, Sel1l deficiency induced unresolved ER stress that triggered thymocyte apoptosis through the PERK pathway. Accordingly, genetically inactivating PERK rescued T cell development from Sel1l-deficient thymocytes. In contrast, IRE1α/XBP1 pathway was induced as a compensatory adaptation to alleviate Sel1l-deficiency-induced ER stress. Dual loss of Sel1l and Xbp1 markedly exacerbated the thymic defect. Our study reveals a critical developmental signal controlled proteostasis mechanism that enforces T cell development to ensure a healthy adaptive immunity.
Collapse
Affiliation(s)
- Xia Liu
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - Jingjing Yu
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - Longyong Xu
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - Katharine Umphred-Wilson
- Department of Pathology, School of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Fanglue Peng
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - Yao Ding
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - Brendan M Barton
- Department of Pathology, School of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Xiangdong Lv
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
| | - Michael Y Zhao
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State UniversityDetroitUnited States
| | - Yuning Hong
- Department of Chemistry and Physics, La Trobe UniversityMelbourneAustralia
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical SchoolAnn ArborUnited States
| | - Stanley Adoro
- Department of Pathology, School of Medicine, Case Western Reserve UniversityClevelandUnited States
| | - Xi Chen
- Department of Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
- Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| |
Collapse
|
5
|
Observing the nonvectorial yet cotranslational folding of a multidomain protein, LDL receptor, in the ER of mammalian cells. Proc Natl Acad Sci U S A 2020; 117:16401-16408. [PMID: 32601215 DOI: 10.1073/pnas.2004606117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Proteins have evolved by incorporating several structural units within a single polypeptide. As a result, multidomain proteins constitute a large fraction of all proteomes. Their domains often fold to their native structures individually and vectorially as each domain emerges from the ribosome or the protein translocation channel, leading to the decreased risk of interdomain misfolding. However, some multidomain proteins fold in the endoplasmic reticulum (ER) nonvectorially via intermediates with nonnative disulfide bonds, which were believed to be shuffled to native ones slowly after synthesis. Yet, the mechanism by which they fold nonvectorially remains unclear. Using two-dimensional (2D) gel electrophoresis and a conformation-specific antibody that recognizes a correctly folded domain, we show here that shuffling of nonnative disulfide bonds to native ones in the most N-terminal region of LDL receptor (LDLR) started at a specific timing during synthesis. Deletion analysis identified a region on LDLR that assisted with disulfide shuffling in the upstream domain, thereby promoting its cotranslational folding. Thus, a plasma membrane-bound multidomain protein has evolved a sequence that promotes the nonvectorial folding of its upstream domains. These findings demonstrate that nonvectorial folding of a multidomain protein in the ER of mammalian cells is more coordinated and elaborated than previously thought. Thus, our findings alter our current view of how a multidomain protein folds nonvectorially in the ER of living cells.
Collapse
|
6
|
Froning K, Maguire J, Sereno A, Huang F, Chang S, Weichert K, Frommelt AJ, Dong J, Wu X, Austin H, Conner EM, Fitchett JR, Heng AR, Balasubramaniam D, Hilgers MT, Kuhlman B, Demarest SJ. Computational stabilization of T cell receptors allows pairing with antibodies to form bispecifics. Nat Commun 2020; 11:2330. [PMID: 32393818 PMCID: PMC7214467 DOI: 10.1038/s41467-020-16231-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 04/20/2020] [Indexed: 01/29/2023] Open
Abstract
Recombinant T cell receptors (TCRs) can be used to redirect naïve T cells to eliminate virally infected or cancerous cells; however, they are plagued by low stability and uneven expression. Here, we use molecular modeling to identify mutations in the TCR constant domains (Cα/Cβ) that increase the unfolding temperature of Cα/Cβ by 20 °C, improve the expression of four separate α/β TCRs by 3- to 10-fold, and improve the assembly and stability of TCRs with poor intrinsic stability. The stabilizing mutations rescue the expression of TCRs destabilized through variable domain mutation. The improved stability and folding of the TCRs reduces glycosylation, perhaps through conformational stabilization that restricts access to N-linked glycosylation enzymes. The Cα/Cβ mutations enables antibody-like expression and assembly of well-behaved bispecific molecules that combine an anti-CD3 antibody with the stabilized TCR. These TCR/CD3 bispecifics can redirect T cells to kill tumor cells with target HLA/peptide on their surfaces in vitro.
Collapse
Affiliation(s)
- Karen Froning
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Jack Maguire
- Program in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Arlene Sereno
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Flora Huang
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Shawn Chang
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Kenneth Weichert
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Anton J Frommelt
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Jessica Dong
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Xiufeng Wu
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Heather Austin
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Elaine M Conner
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Jonathan R Fitchett
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Aik Roy Heng
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | | | - Mark T Hilgers
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Stephen J Demarest
- Eli Lilly Biotechnology Center, 10300 Campus Point Drive, San Diego, CA, 92121, USA.
| |
Collapse
|
7
|
Abstract
One-fourth of eukaryotic genes code for integral membrane proteins, nearly all of which are inserted and assembled at the endoplasmic reticulum (ER). The defining feature of membrane proteins is one or more transmembrane domains (TMDs). During membrane protein biogenesis, TMDs are selectively recognized, shielded, and chaperoned into the lipid bilayer, where they often assemble with other TMDs. If maturation fails, exposed TMDs serve as a cue for engagement of degradation pathways. Thus, TMD-recognition factors in the cytosol and ER are essential for membrane protein biogenesis and quality control. Here, we discuss the growing assortment of cytosolic and membrane-embedded TMD-recognition factors, the pathways within which they operate, and mechanistic principles of recognition.
Collapse
|
8
|
Sádio F, Stadlmayr G, Stadlbauer K, Gräf M, Scharrer A, Rüker F, Wozniak-Knopp G. Stabilization of soluble high-affinity T-cell receptor with de novo disulfide bonds. FEBS Lett 2019; 594:477-490. [PMID: 31552676 PMCID: PMC7027902 DOI: 10.1002/1873-3468.13616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/04/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Soluble T‐cell receptors (TCRs) have recently gained visibility as target‐recognition units of anticancer immunotherapeutic agents. Here, we improved the thermal stability of the well‐expressed high‐affinity A6 TCR by introducing pairs of cysteines in the invariable parts of the α‐ and β‐chain. A mutant with a novel intradomain disulfide bond in each chain also tested superior to the wild‐type in the accelerated stability assay. Binding of the mutant to the soluble cognate peptide (cp)–MHC and to the peptide‐loaded T2 cell line was equal to the wild‐type A6 TCR. The same stabilization motif worked efficiently in TCRs with different specificities, such as DMF5 and 1G4. Altogether, the biophysical properties of the soluble TCR molecule could be improved, without affecting its expression level and antigen‐binding specificity.
Collapse
Affiliation(s)
- Flávio Sádio
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gerhard Stadlmayr
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Katharina Stadlbauer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Maximilian Gräf
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Agnes Scharrer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Florian Rüker
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gordana Wozniak-Knopp
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| |
Collapse
|
9
|
Epithelial sodium channel biogenesis and quality control in the early secretory pathway. Curr Opin Nephrol Hypertens 2018; 27:364-372. [DOI: 10.1097/mnh.0000000000000438] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
10
|
Natarajan K, McShan AC, Jiang J, Kumirov VK, Wang R, Zhao H, Schuck P, Tilahun ME, Boyd LF, Ying J, Bax A, Margulies DH, Sgourakis NG. An allosteric site in the T-cell receptor Cβ domain plays a critical signalling role. Nat Commun 2017; 8:15260. [PMID: 28508865 PMCID: PMC5440810 DOI: 10.1038/ncomms15260] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/14/2017] [Indexed: 12/21/2022] Open
Abstract
The molecular mechanism through which the interaction of a clonotypic αβ T-cell receptor (TCR) with a peptide-loaded major histocompatibility complex (p/MHC) leads to T-cell activation is not yet fully understood. Here we exploit a high-affinity TCR (B4.2.3) to examine the structural changes that accompany binding to its p/MHC ligand (P18-I10/H2-Dd). In addition to conformational changes in complementarity-determining regions (CDRs) of the TCR seen in comparison of unliganded and bound X-ray structures, NMR characterization of the TCR β-chain dynamics reveals significant chemical shift effects in sites removed from the MHC-binding site. Remodelling of electrostatic interactions near the Cβ H3 helix at the membrane-proximal face of the TCR, a region implicated in interactions with the CD3 co-receptor, suggests a possible role for an allosteric mechanism in TCR signalling. The contribution of these TCR residues to signal transduction is supported by mutagenesis and T-cell functional assays.
Collapse
MESH Headings
- Allosteric Site/immunology
- Animals
- Complementarity Determining Regions/chemistry
- Complementarity Determining Regions/metabolism
- Crystallography, X-Ray
- Major Histocompatibility Complex/immunology
- Mice
- Molecular Dynamics Simulation
- Mutagenesis
- Peptides/metabolism
- Protein Binding/immunology
- Protein Domains/immunology
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
Collapse
Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Andrew C. McShan
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Vlad K Kumirov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Rui Wang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Huaying Zhao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Peter Schuck
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Mulualem E. Tilahun
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Lisa F. Boyd
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nikolaos G. Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| |
Collapse
|
11
|
Reitberger S, Haimerl P, Aschenbrenner I, Esser-von Bieren J, Feige MJ. Assembly-induced folding regulates interleukin 12 biogenesis and secretion. J Biol Chem 2017; 292:8073-8081. [PMID: 28325840 DOI: 10.1074/jbc.m117.782284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/17/2017] [Indexed: 12/17/2022] Open
Abstract
Members of the IL-12 family perform essential functions in immunoregulation by connecting innate and adaptive immunity and are emerging therapeutic targets. They are unique among other interleukins in forming heterodimers that arise from extensive subunit sharing within the family, leading to the production of at least four functionally distinct heterodimers from only five subunits. This raises important questions about how the assembly of IL-12 family members is regulated and controlled in the cell. Here, using cell-biological approaches, we have dissected basic principles that underlie the biogenesis of the founding member of the family, IL-12. Within the native IL-12 heterodimer, composed of IL-12α and IL-12β, IL-12α possesses three intramolecular and one intermolecular disulfide bridges. We show that, in isolation, IL-12α fails to form its native structure but, instead, misfolds, forming incorrect disulfide bonds. Co-expression of its β subunit inhibits misfolding and thus allows secretion of biologically active heterodimeric IL-12. On the basis of these findings, we identified the disulfide bonds in IL-12α that are critical for assembly-induced secretion and biological activity of IL-12 versus misfolding and degradation of IL-12α. Surprisingly, two of the three disulfide bridges in IL-12α are dispensable for IL-12 secretion, stability, and biological activity. Extending our findings, we show that misfolding also occurs for IL-23α, another IL-12 family protein. Our results indicate that assembly-induced folding is key in IL-12 family biogenesis and secretion. The identification of essential disulfide bonds that underlie this process lays the basis for a simplified yet functional IL-12 cytokine.
Collapse
Affiliation(s)
- Susanne Reitberger
- From the Center for Integrated Protein Science at the Department of Chemistry and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany and
| | - Pascal Haimerl
- the Center of Allergy and Environment, Technical University of Munich and Helmholtz Zentrum München, 80802 Munich, Germany
| | - Isabel Aschenbrenner
- From the Center for Integrated Protein Science at the Department of Chemistry and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany and
| | - Julia Esser-von Bieren
- the Center of Allergy and Environment, Technical University of Munich and Helmholtz Zentrum München, 80802 Munich, Germany
| | - Matthias J Feige
- From the Center for Integrated Protein Science at the Department of Chemistry and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany and
| |
Collapse
|
12
|
Buck TM, Jordahl AS, Yates ME, Preston GM, Cook E, Kleyman TR, Brodsky JL. Interactions between intersubunit transmembrane domains regulate the chaperone-dependent degradation of an oligomeric membrane protein. Biochem J 2017; 474:357-376. [PMID: 27903760 PMCID: PMC5423784 DOI: 10.1042/bcj20160760] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/22/2022]
Abstract
In the kidney, the epithelial sodium channel (ENaC) regulates blood pressure through control of sodium and volume homeostasis, and in the lung, ENaC regulates the volume of airway and alveolar fluids. ENaC is a heterotrimer of homologous α-, β- and γ-subunits, and assembles in the endoplasmic reticulum (ER) before it traffics to and functions at the plasma membrane. Improperly folded or orphaned ENaC subunits are subject to ER quality control and targeted for ER-associated degradation (ERAD). We previously established that a conserved, ER lumenal, molecular chaperone, Lhs1/GRP170, selects αENaC, but not β- or γ-ENaC, for degradation when the ENaC subunits were individually expressed. We now find that when all three subunits are co-expressed, Lhs1-facilitated ERAD was blocked. To determine which domain-domain interactions between the ENaC subunits are critical for chaperone-dependent quality control, we employed a yeast model and expressed chimeric α/βENaC constructs in the context of the ENaC heterotrimer. We discovered that the βENaC transmembrane domain was sufficient to prevent the Lhs1-dependent degradation of the α-subunit in the context of the ENaC heterotrimer. Our work also found that Lhs1 delivers αENaC for proteasome-mediated degradation after the protein has become polyubiquitinated. These data indicate that the Lhs1 chaperone selectively recognizes an immature form of αENaC, one which has failed to correctly assemble with the other channel subunits via its transmembrane domain.
Collapse
Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Alexa S Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Megan E Yates
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - G Michael Preston
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Emily Cook
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Thomas R Kleyman
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, PA, U.S.A
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, U.S.A
| |
Collapse
|
13
|
Schaefer RM, Heasley LR, Odde DJ, McMurray MA. Kinetic partitioning during de novo septin filament assembly creates a critical G1 "window of opportunity" for mutant septin function. Cell Cycle 2016; 15:2441-53. [PMID: 27398993 DOI: 10.1080/15384101.2016.1196304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Septin proteins form highly conserved cytoskeletal filaments composed of hetero-oligomers with strict subunit stoichiometry. Mutations within one hetero-oligomerization interface (the "G" interface) bias the mutant septin toward conformations that are incompatible with filament assembly, causing disease in humans and, in budding yeast cells, temperature-sensitive defects in cytokinesis. We previously found that, when the amount of other hetero-oligomerization partners is limiting, wild-type and G interface-mutant alleles of a given yeast septin "compete" along parallel but distinct folding pathways for occupancy of a limited number of positions within septin hetero-octamers. Here, we synthesize a mathematical model that outlines the requirements for this phenomenon: if a wild-type septin traverses a folding pathway that includes a single rate-limiting folding step, the acquisition by a mutant septin of additional slow folding steps creates an initially large disparity between wild-type and mutant in the cellular concentrations of oligomerization-competent monomers. When the 2 alleles are co-expressed, this kinetic disparity results in mutant exclusion from hetero-oligomers, even when the folded mutant monomer is oligomerization-competent. To test this model experimentally, we first visualize the kinetic delay in mutant oligomerization in living cells, and then narrow or widen the "window of opportunity" for mutant septin oligomerization by altering the length of the G1 phase of the yeast cell cycle, and observe the predicted exacerbation or suppression, respectively, of mutant cellular phenotypes. These findings reveal a fundamental kinetic principle governing in vivo assembly of multiprotein complexes, independent of the ability of the subunits to associate with each other.
Collapse
Affiliation(s)
- Rachel M Schaefer
- a Department of Cell and Developmental Biology , University of Colorado Anschutz Medical Campus , Aurora , CO , USA
| | - Lydia R Heasley
- a Department of Cell and Developmental Biology , University of Colorado Anschutz Medical Campus , Aurora , CO , USA
| | - David J Odde
- b Department of Biomedical Engineering , University of Minnesota , Minneapolis , MN , USA
| | - Michael A McMurray
- a Department of Cell and Developmental Biology , University of Colorado Anschutz Medical Campus , Aurora , CO , USA
| |
Collapse
|
14
|
Ellgaard L, McCaul N, Chatsisvili A, Braakman I. Co- and Post-Translational Protein Folding in the ER. Traffic 2016; 17:615-38. [PMID: 26947578 DOI: 10.1111/tra.12392] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 02/26/2016] [Accepted: 03/03/2016] [Indexed: 12/19/2022]
Abstract
The biophysical rules that govern folding of small, single-domain proteins in dilute solutions are now quite well understood. The mechanisms underlying co-translational folding of multidomain and membrane-spanning proteins in complex cellular environments are often less clear. The endoplasmic reticulum (ER) produces a plethora of membrane and secretory proteins, which must fold and assemble correctly before ER exit - if these processes fail, misfolded species accumulate in the ER or are degraded. The ER differs from other cellular organelles in terms of the physicochemical environment and the variety of ER-specific protein modifications. Here, we review chaperone-assisted co- and post-translational folding and assembly in the ER and underline the influence of protein modifications on these processes. We emphasize how method development has helped advance the field by allowing researchers to monitor the progression of folding as it occurs inside living cells, while at the same time probing the intricate relationship between protein modifications during folding.
Collapse
Affiliation(s)
- Lars Ellgaard
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nicholas McCaul
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna Chatsisvili
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| |
Collapse
|