1
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Srinivasan S, Zhu C, McShan AC. Structure, function, and immunomodulation of the CD8 co-receptor. Front Immunol 2024; 15:1412513. [PMID: 39253084 PMCID: PMC11381289 DOI: 10.3389/fimmu.2024.1412513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 08/05/2024] [Indexed: 09/11/2024] Open
Abstract
Expressed on the surface of CD8+ T cells, the CD8 co-receptor is a key component of the T cells that contributes to antigen recognition, immune cell maturation, and immune cell signaling. While CD8 is widely recognized as a co-stimulatory molecule for conventional CD8+ αβ T cells, recent reports highlight its multifaceted role in both adaptive and innate immune responses. In this review, we discuss the utility of CD8 in relation to its immunomodulatory properties. We outline the unique structure and function of different CD8 domains (ectodomain, hinge, transmembrane, cytoplasmic tail) in the context of the distinct properties of CD8αα homodimers and CD8αβ heterodimers. We discuss CD8 features commonly used to construct chimeric antigen receptors for immunotherapy. We describe the molecular interactions of CD8 with classical MHC-I, non-classical MHCs, and Lck partners involved in T cell signaling. Engineered and naturally occurring CD8 mutations that alter immune responses are discussed. The applications of anti-CD8 monoclonal antibodies (mABs) that target CD8 are summarized. Finally, we examine the unique structure and function of several CD8/mAB complexes. Collectively, these findings reveal the promising immunomodulatory properties of CD8 and CD8 binding partners, not only to uncover basic immune system function, but to advance efforts towards translational research for targeted immunotherapy.
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Affiliation(s)
- Shreyaa Srinivasan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
| | - Cheng Zhu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Andrew C McShan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, United States
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2
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Chu GJ, Bailey CG, Nagarajah R, Sagnella SM, Adelstein S, Rasko JEJ. The 4-1BBζ costimulatory domain in chimeric antigen receptors enhances CD8+ T-cell functionality following T-cell receptor stimulation. Cancer Cell Int 2023; 23:327. [PMID: 38105188 PMCID: PMC10726568 DOI: 10.1186/s12935-023-03171-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Chimeric antigen receptor (CAR) T-cells have revolutionized the treatment of CD19- and B-cell maturation antigen-positive haematological malignancies. However, the effect of a CAR construct on the function of T-cells stimulated via their endogenous T-cell receptors (TCRs) has yet to be comprehensively investigated. METHODS Experiments were performed to systematically assess TCR signalling and function in CAR T-cells using anti-mesothelin human CAR T-cells as a model system. CAR T-cells expressing the CD28 or 4-1BB costimulatory endodomains were manufactured and compared to both untransduced T-cells and CAR T-cells with a non-functional endodomain. These cell products were treated with staphylococcal enterotoxin B to stimulate the TCR, and in vitro functional assays were performed by flow cytometry. RESULTS Increased proliferation, CD69 expression and IFNγ production were identified in CD8+ 4-1BBζ CAR T-cells compared to control untransduced CD8+ T-cells. These functional differences were associated with higher levels of phosphorylated ZAP70 after stimulation. In addition, these functional differences were associated with a differing immunophenotype, with a more than two-fold increase in central memory cells in CD8+ 4-1BBζ CAR T-cell products. CONCLUSION Our data indicate that the 4-1BBζ CAR enhances CD8+ TCR-mediated function. This could be beneficial if the TCR targets epitopes on malignant tissues or infectious agents, but detrimental if the TCR targets autoantigens.
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Affiliation(s)
- Gerard J Chu
- Gene and Stem Cell Therapy Program Centenary Institute, Camperdown, NSW, Australia
- Department of Clinical Immunology and Allergy, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Charles G Bailey
- Gene and Stem Cell Therapy Program Centenary Institute, Camperdown, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Cancer & Gene Regulation Laboratory Centenary Institute, Camperdown, NSW, Australia
| | - Rajini Nagarajah
- Gene and Stem Cell Therapy Program Centenary Institute, Camperdown, NSW, Australia
| | - Sharon M Sagnella
- Cell & Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Stephen Adelstein
- Department of Clinical Immunology and Allergy, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - John E J Rasko
- Gene and Stem Cell Therapy Program Centenary Institute, Camperdown, NSW, Australia.
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia.
- Cell & Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
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3
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Sun Y, Yang XN, Yang SS, Lyu YZ, Zhang B, Liu KW, Li N, Cui JC, Huang GX, Liu CL, Xu J, Mi JQ, Chen Z, Fan XH, Chen SJ, Chen S. Antigen-induced chimeric antigen receptor multimerization amplifies on-tumor cytotoxicity. Signal Transduct Target Ther 2023; 8:445. [PMID: 38062078 PMCID: PMC10703879 DOI: 10.1038/s41392-023-01686-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 12/18/2023] Open
Abstract
Ligand-induced receptor dimerization or oligomerization is a widespread mechanism for ensuring communication specificity, safeguarding receptor activation, and facilitating amplification of signal transduction across the cellular membrane. However, cell-surface antigen-induced multimerization (dubbed AIM herein) has not yet been consciously leveraged in chimeric antigen receptor (CAR) engineering for enriching T cell-based therapies. We co-developed ciltacabtagene autoleucel (cilta-cel), whose CAR incorporates two B-cell maturation antigen (BCMA)-targeted nanobodies in tandem, for treating multiple myeloma. Here we elucidated a structural and functional model in which BCMA-induced cilta-cel CAR multimerization amplifies myeloma-targeted T cell-mediated cytotoxicity. Crystallographic analysis of BCMA-nanobody complexes revealed atomic details of antigen-antibody hetero-multimerization whilst analytical ultracentrifugation and small-angle X-ray scattering characterized interdependent BCMA apposition and CAR juxtaposition in solution. BCMA-induced nanobody CAR multimerization enhanced cytotoxicity, alongside elevated immune synapse formation and cytotoxicity-mediating cytokine release, towards myeloma-derived cells. Our results provide a framework for contemplating the AIM approach in designing next-generation CARs.
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Affiliation(s)
- Yan Sun
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiu-Na Yang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Shuang-Shuang Yang
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yi-Zhu Lyu
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
- Department of Hematology, Second Hospital of Dalian Medical University, Dalian, 116023, China
| | - Bing Zhang
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Kai-Wen Liu
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Na Li
- National Facility for Protein Science Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Jia-Chen Cui
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Guang-Xiang Huang
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Cheng-Lin Liu
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jie Xu
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jian-Qing Mi
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Zhu Chen
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiao-Hu Fan
- Legend Biotech China, Nanjing, 211112, China.
- Wondercel Biotechnology, Shenzhen, 518052, China.
| | - Sai-Juan Chen
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Shuo Chen
- Shanghai Institute of Hematology, National Research Center for Translational Medicine, State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Shanghai Immune Therapy Institute, Shanghai Cancer Institute, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
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4
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Beppler C, Eichorst J, Marchuk K, Cai E, Castellanos CA, Sriram V, Roybal KT, Krummel MF. Hyperstabilization of T cell microvilli contacts by chimeric antigen receptors. J Cell Biol 2023; 222:e202205118. [PMID: 36520493 PMCID: PMC9757849 DOI: 10.1083/jcb.202205118] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/25/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
T cells typically recognize their ligands using a defined cell biology-the scanning of their membrane microvilli (MV) to palpate their environment-while that same membrane scaffolds T cell receptors (TCRs) that can signal upon ligand binding. Chimeric antigen receptors (CARs) present both a therapeutic promise and a tractable means to study the interplay between receptor affinity, MV dynamics and T cell function. CARs are often built using single-chain variable fragments (scFvs) with far greater affinity than that of natural TCRs. We used high-resolution lattice lightsheet (LLS) and total internal reflection fluorescence (TIRF) imaging to visualize MV scanning in the context of variations in CAR design. This demonstrated that conventional CARs hyper-stabilized microvillar contacts relative to TCRs. Reducing receptor affinity, antigen density, and/or multiplicity of receptor binding sites normalized microvillar dynamics and synapse resolution, and effector functions improved with reduced affinity and/or antigen density, highlighting the importance of understanding the underlying cell biology when designing receptors for optimal antigen engagement.
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Affiliation(s)
- Casey Beppler
- Department of Pathology and ImmunoX, University of California, San Francisco, San Francisco, CA, USA
| | - John Eichorst
- Biological Imaging Development CoLab, University of California, San Francisco, San Francisco, CA, USA
| | - Kyle Marchuk
- Biological Imaging Development CoLab, University of California, San Francisco, San Francisco, CA, USA
| | - En Cai
- Department of Pathology and ImmunoX, University of California, San Francisco, San Francisco, CA, USA
| | - Carlos A. Castellanos
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA, USA
| | | | - Kole T. Roybal
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
- Parker Institute for Cancer Immunotherapy, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Helen Diller Comprehensive Cancer Center, San Francisco, CA, USA
| | - Matthew F. Krummel
- Department of Pathology and ImmunoX, University of California, San Francisco, San Francisco, CA, USA
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5
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Labanieh L, Majzner RG, Klysz D, Sotillo E, Fisher CJ, Vilches-Moure JG, Pacheco KZB, Malipatlolla M, Xu P, Hui JH, Murty T, Theruvath J, Mehta N, Yamada-Hunter SA, Weber EW, Heitzeneder S, Parker KR, Satpathy AT, Chang HY, Lin MZ, Cochran JR, Mackall CL. Enhanced safety and efficacy of protease-regulated CAR-T cell receptors. Cell 2022; 185:1745-1763.e22. [PMID: 35483375 PMCID: PMC9467936 DOI: 10.1016/j.cell.2022.03.041] [Citation(s) in RCA: 106] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 01/04/2022] [Accepted: 03/29/2022] [Indexed: 11/22/2022]
Abstract
Regulatable CAR platforms could circumvent toxicities associated with CAR-T therapy, but existing systems have shortcomings including leakiness and attenuated activity. Here, we present SNIP CARs, a protease-based platform for regulating CAR activity using an FDA-approved small molecule. Design iterations yielded CAR-T cells that manifest full functional capacity with drug and no leaky activity in the absence of drug. In numerous models, SNIP CAR-T cells were more potent than constitutive CAR-T cells and showed diminished T cell exhaustion and greater stemness. In a ROR1-based CAR lethality model, drug cessation following toxicity onset reversed toxicity, thereby credentialing the platform as a safety switch. In the same model, reduced drug dosing opened a therapeutic window that resulted in tumor eradication in the absence of toxicity. SNIP CARs enable remote tuning of CAR activity, which provides solutions to safety and efficacy barriers that are currently limiting progress in using CAR-T cells to treat solid tumors.
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Affiliation(s)
- Louai Labanieh
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robbie G Majzner
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dorota Klysz
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elena Sotillo
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chris J Fisher
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - José G Vilches-Moure
- Department of Comparative Medicine, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Kaithlen Zen B Pacheco
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Meena Malipatlolla
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peng Xu
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jessica H Hui
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tara Murty
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Medical Scientist Training Program, Stanford University School of Medicine, Stanford, CA 94305, USA; Biophysics Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Johanna Theruvath
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nishant Mehta
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Sean A Yamada-Hunter
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Evan W Weber
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sabine Heitzeneder
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin R Parker
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jennifer R Cochran
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Crystal L Mackall
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
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6
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Elazar A, Chandler NJ, Davey AS, Weinstein JY, Nguyen JV, Trenker R, Cross RS, Jenkins MR, Call MJ, Call ME, Fleishman SJ. De novo-designed transmembrane domains tune engineered receptor functions. eLife 2022; 11:75660. [PMID: 35506657 PMCID: PMC9068223 DOI: 10.7554/elife.75660] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/14/2022] [Indexed: 12/20/2022] Open
Abstract
De novo-designed receptor transmembrane domains (TMDs) present opportunities for precise control of cellular receptor functions. We developed a de novo design strategy for generating programmed membrane proteins (proMPs): single-pass α-helical TMDs that self-assemble through computationally defined and crystallographically validated interfaces. We used these proMPs to program specific oligomeric interactions into a chimeric antigen receptor (CAR) that we expressed in mouse primary T cells and found that both in vitro CAR T cell cytokine release and in vivo antitumor activity scaled linearly with the oligomeric state encoded by the receptor TMD, from monomers up to tetramers. All programmed CARs stimulated substantially lower T cell cytokine release relative to the commonly used CD28 TMD, which we show elevated cytokine release through lateral recruitment of the endogenous T cell costimulatory receptor CD28. Precise design using orthogonal and modular TMDs thus provides a new way to program receptor structure and predictably tune activity for basic or applied synthetic biology.
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Affiliation(s)
- Assaf Elazar
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Nicholas J Chandler
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Ashleigh S Davey
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Jonathan Y Weinstein
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Julie V Nguyen
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Raphael Trenker
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Ryan S Cross
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.,Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Misty R Jenkins
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.,Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,La Trobe Institute of Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Melissa J Call
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew E Call
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sarel J Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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7
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Chandler NJ, Call MJ, Call ME. T Cell Activation Machinery: Form and Function in Natural and Engineered Immune Receptors. Int J Mol Sci 2020; 21:E7424. [PMID: 33050044 PMCID: PMC7582382 DOI: 10.3390/ijms21197424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022] Open
Abstract
The impressive success of chimeric antigen receptor (CAR)-T cell therapies in treating advanced B-cell malignancies has spurred a frenzy of activity aimed at developing CAR-T therapies for other cancers, particularly solid tumors, and optimizing engineered T cells for maximum clinical benefit in many different disease contexts. A rapidly growing body of design work is examining every modular component of traditional single-chain CARs as well as expanding out into many new and innovative engineered immunoreceptor designs that depart from this template. New approaches to immune cell and receptor engineering are being reported with rapidly increasing frequency, and many recent high-quality reviews (including one in this special issue) provide comprehensive coverage of the history and current state of the art in CAR-T and related cellular immunotherapies. In this review, we step back to examine our current understanding of the structure-function relationships in natural and engineered lymphocyte-activating receptors, with an eye towards evaluating how well the current-generation CAR designs recapitulate the most desirable features of their natural counterparts. We identify key areas that we believe are under-studied and therefore represent opportunities to further improve our grasp of form and function in natural and engineered receptors and to rationally design better therapeutics.
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Affiliation(s)
- Nicholas J. Chandler
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia; (N.J.C.); (M.J.C.)
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Melissa J. Call
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia; (N.J.C.); (M.J.C.)
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Matthew E. Call
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia; (N.J.C.); (M.J.C.)
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
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8
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Salzer B, Schueller CM, Zajc CU, Peters T, Schoeber MA, Kovacic B, Buri MC, Lobner E, Dushek O, Huppa JB, Obinger C, Putz EM, Holter W, Traxlmayr MW, Lehner M. Engineering AvidCARs for combinatorial antigen recognition and reversible control of CAR function. Nat Commun 2020; 11:4166. [PMID: 32820173 PMCID: PMC7441178 DOI: 10.1038/s41467-020-17970-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 07/23/2020] [Indexed: 12/13/2022] Open
Abstract
T cells engineered to express chimeric antigen receptors (CAR-T cells) have shown impressive clinical efficacy in the treatment of B cell malignancies. However, the development of CAR-T cell therapies for solid tumors is hampered by the lack of truly tumor-specific antigens and poor control over T cell activity. Here we present an avidity-controlled CAR (AvidCAR) platform with inducible and logic control functions. The key is the combination of (i) an improved CAR design which enables controlled CAR dimerization and (ii) a significant reduction of antigen-binding affinities to introduce dependence on bivalent interaction, i.e. avidity. The potential and versatility of the AvidCAR platform is exemplified by designing ON-switch CARs, which can be regulated with a clinically applied drug, and AND-gate CARs specifically recognizing combinations of two antigens. Thus, we expect that AvidCARs will be a highly valuable platform for the development of controllable CAR therapies with improved tumor specificity.
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MESH Headings
- Animals
- Antigens, Neoplasm/immunology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Cells, Cultured
- Cytokines/immunology
- Cytokines/metabolism
- Cytotoxicity, Immunologic/immunology
- Humans
- Immunotherapy, Adoptive/methods
- Lymphocyte Activation/immunology
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Neoplasms/immunology
- Neoplasms/pathology
- Neoplasms/therapy
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Chimeric Antigen/genetics
- Receptors, Chimeric Antigen/immunology
- Receptors, Chimeric Antigen/metabolism
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Benjamin Salzer
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
- Christian Doppler Laboratory for Next Generation CAR T Cells, 1090, Vienna, Austria
| | | | - Charlotte U Zajc
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
- Christian Doppler Laboratory for Next Generation CAR T Cells, 1090, Vienna, Austria
| | - Timo Peters
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, 1090, Vienna, Austria
| | - Michael A Schoeber
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
| | - Boris Kovacic
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
| | - Michelle C Buri
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
| | - Elisabeth Lobner
- Department of Biotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Johannes B Huppa
- Center for Pathophysiology, Infectiology and Immunology, Institute for Hygiene and Applied Immunology, Medical University of Vienna, 1090, Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Eva M Putz
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
| | - Wolfgang Holter
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria
- Department of Pediatrics, St. Anna Kinderspital, Medical University of Vienna, 1090, Vienna, Austria
| | - Michael W Traxlmayr
- Christian Doppler Laboratory for Next Generation CAR T Cells, 1090, Vienna, Austria.
- Department of Chemistry, Institute of Biochemistry, University of Natural Resources and Life Sciences, 1190, Vienna, Austria.
| | - Manfred Lehner
- St. Anna Children's Cancer Research Institute (CCRI), 1090, Vienna, Austria.
- Christian Doppler Laboratory for Next Generation CAR T Cells, 1090, Vienna, Austria.
- Department of Pediatrics, St. Anna Kinderspital, Medical University of Vienna, 1090, Vienna, Austria.
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9
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Leddon SA, Fettis MM, Abramo K, Kelly R, Oleksyn D, Miller J. The CD28 Transmembrane Domain Contains an Essential Dimerization Motif. Front Immunol 2020; 11:1519. [PMID: 32765524 PMCID: PMC7378745 DOI: 10.3389/fimmu.2020.01519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
CD28 plays a critical role in regulating immune responses both by enhancing effector T cell activation and differentiation and controlling the development and function of regulatory T cells. CD28 is expressed at the cell surface as a disulfide linked homodimer that is thought to bind ligand monovalently. How ligand binding triggers CD28 to induce intracellular signaling as well as the proximal signaling pathways that are induced are not well-understood. In addition, recent data suggest inside-out signaling initiated by the T cell antigen receptor can enhance CD28 ligand binding, possibly by inducing a rearrangement of the CD28 dimer interface to allow for bivalent binding. To understand how possible conformational changes during ligand-induced receptor triggering and inside-out signaling are mediated, we examined the CD28 transmembrane domain. We identified an evolutionarily conserved YxxxxT motif that is shared with CTLA-4 and resembles the transmembrane dimerization motif within CD3ζ. We show that the CD28 transmembrane domain can drive protein dimerization in a bacterial expression system at levels equivalent to the well-known glycophorin A transmembrane dimerization motif. In addition, ectopic expression of the CD28 transmembrane domain into monomeric human CD25 can drive dimerization in murine T cells as detected by an increase in FRET by flow cytometry. Mutation of the polar YxxxxT motif to hydrophobic leucine residues (Y145L/T150L) attenuated CD28 transmembrane mediated dimerization in both the bacterial and mammalian assays. Introduction of the Y145L/T150L mutation of the CD28 transmembrane dimerization motif into the endogenous CD28 locus by CRISPR resulted in a dramatic loss in CD28 cell surface expression. These data suggest that under physiological conditions the YxxxxT dimerization motif within the CD28 transmembrane domain plays a critical role in the assembly and/or expression of stable CD28 dimers at the cell surface.
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Affiliation(s)
- Scott A Leddon
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Margaret M Fettis
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Kristin Abramo
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Ryan Kelly
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - David Oleksyn
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
| | - Jim Miller
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester Medical Center, Rochester, NY, United States
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10
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Liu Y, Cuendet MA, Goffin L, Šachl R, Cebecauer M, Cariolato L, Guillaume P, Reichenbach P, Irving M, Coukos G, Luescher IF. CD8 Binding of MHC-Peptide Complexes in cis or trans Regulates CD8 + T-cell Responses. J Mol Biol 2019; 431:4941-4958. [PMID: 31704286 DOI: 10.1016/j.jmb.2019.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/21/2019] [Accepted: 10/23/2019] [Indexed: 11/19/2022]
Abstract
The coreceptor CD8αβ can greatly promote activation of T cells by strengthening T-cell receptor (TCR) binding to cognate peptide-MHC complexes (pMHC) on antigen presenting cells and by bringing p56Lck to TCR/CD3. Here, we demonstrate that CD8 can also bind to pMHC on the T cell (in cis) and that this inhibits their activation. Using molecular modeling, fluorescence resonance energy transfer experiments on living cells, biochemical and mutational analysis, we show that CD8 binding to pMHC in cis involves a different docking mode and is regulated by posttranslational modifications including a membrane-distal interchain disulfide bond and negatively charged O-linked glycans near positively charged sequences on the CD8β stalk. These modifications distort the stalk, thus favoring CD8 binding to pMHC in cis. Differential binding of CD8 to pMHC in cis or trans is a means to regulate CD8+ T-cell responses and provides new translational opportunities.
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Affiliation(s)
- Yang Liu
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Michel A Cuendet
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland; Department of Physiology and Biophysics, Weill Cornell Medicine, New York, USA
| | - Laurence Goffin
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Radek Šachl
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, 18223 Prague, Czech Republic
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, 18223 Prague, Czech Republic
| | - Luca Cariolato
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Philippe Guillaume
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Patrick Reichenbach
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Melita Irving
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - George Coukos
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland
| | - Immanuel F Luescher
- Ludwig Institute for Cancer Research, University of Lausanne, and Department of Oncology, University Hospital of Lausanne, 1009, Lausanne, Switzerland.
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11
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Weinberg F, Griffin R, Fröhlich M, Heining C, Braun S, Spohr C, Iconomou M, Hollek V, Röring M, Horak P, Kreutzfeldt S, Warsow G, Hutter B, Uhrig S, Neumann O, Reuss D, Heiland DH, von Kalle C, Weichert W, Stenzinger A, Brors B, Glimm H, Fröhling S, Brummer T. Identification and characterization of a BRAF fusion oncoprotein with retained autoinhibitory domains. Oncogene 2019; 39:814-832. [PMID: 31558800 DOI: 10.1038/s41388-019-1021-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/14/2022]
Abstract
Fusion proteins involving the BRAF serine/threonine kinase occur in many cancers. The oncogenic potential of BRAF fusions has been attributed to the loss of critical N-terminal domains that mediate BRAF autoinhibition. We used whole-exome and RNA sequencing in a patient with glioblastoma multiforme to identify a rearrangement between TTYH3, encoding a membrane-resident, calcium-activated chloride channel, and BRAF intron 1, resulting in a TTYH3-BRAF fusion protein that retained all features essential for BRAF autoinhibition. Accordingly, the BRAF moiety of the fusion protein alone, which represents full-length BRAF without the amino acids encoded by exon 1 (BRAFΔE1), did not induce MEK/ERK phosphorylation or transformation. Likewise, neither the TTYH3 moiety of the fusion protein nor full-length TTYH3 provoked ERK pathway activity or transformation. In contrast, TTYH3-BRAF displayed increased MEK phosphorylation potential and transforming activity, which were caused by TTYH3-mediated tethering of near-full-length BRAF to the (endo)membrane system. Consistent with this mechanism, a synthetic approach, in which BRAFΔE1 was tethered to the membrane by fusing it to the cytoplasmic tail of CD8 also induced transformation. Furthermore, we demonstrate that TTYH3-BRAF signals largely independent of a functional RAS binding domain, but requires an intact BRAF dimer interface and activation loop phosphorylation sites. Cells expressing TTYH3-BRAF exhibited increased MEK/ERK signaling, which was blocked by clinically achievable concentrations of sorafenib, trametinib, and the paradox breaker PLX8394. These data provide the first example of a fully autoinhibited BRAF protein whose oncogenic potential is dictated by a distinct fusion partner and not by a structural change in BRAF itself.
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Affiliation(s)
- Florian Weinberg
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Centre for Biological Signalling Studies BIOSS, University of Freiburg, Freiburg, Germany
| | - Ricarda Griffin
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martina Fröhlich
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
| | - Christoph Heining
- Department of Translational Medical Oncology, NCT Dresden, Dresden, and DKFZ, Heidelberg, Germany.,University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany.,German Cancer Consortium (DKTK), Dresden, Germany
| | - Sandra Braun
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Centre for Biological Signalling Studies BIOSS, University of Freiburg, Freiburg, Germany
| | - Corinna Spohr
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany
| | - Mary Iconomou
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Viola Hollek
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Röring
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Peter Horak
- Department of Translational Medical Oncology, NCT Heidelberg and DKFZ, Heidelberg, Germany.,DKTK, Heidelberg, Germany
| | - Simon Kreutzfeldt
- Department of Translational Medical Oncology, NCT Heidelberg and DKFZ, Heidelberg, Germany.,DKTK, Heidelberg, Germany
| | - Gregor Warsow
- Omics IT and Data Management Core Facility, DKFZ, Heidelberg, Germany.,Division of Theoretical Bioinformatics, DKFZ, Heidelberg, Germany
| | - Barbara Hutter
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany
| | - Sebastian Uhrig
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Olaf Neumann
- DKTK, Heidelberg, Germany.,Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany
| | - David Reuss
- DKTK, Heidelberg, Germany.,Department of Neuropathology, Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.,Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), German Consortium for Translational Cancer Research (DKTK), Heidelberg, Germany
| | - Dieter Henrik Heiland
- Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Translational NeuroOncology Research Group, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christof von Kalle
- Department of Translational Oncology, NCT Heidelberg and DKFZ, Heidelberg, Germany
| | - Wilko Weichert
- Institute of Pathology, Technical University Munich, Munich, Germany.,DKTK, Munich, Germany
| | - Albrecht Stenzinger
- DKTK, Heidelberg, Germany.,Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany
| | - Benedikt Brors
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT) Heidelberg, Heidelberg, Germany.,DKTK, Heidelberg, Germany
| | - Hanno Glimm
- Department of Translational Medical Oncology, NCT Dresden, Dresden, and DKFZ, Heidelberg, Germany.,University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany.,German Cancer Consortium (DKTK), Dresden, Germany
| | - Stefan Fröhling
- Department of Translational Medical Oncology, NCT Heidelberg and DKFZ, Heidelberg, Germany. .,DKTK, Heidelberg, Germany.
| | - Tilman Brummer
- Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,Centre for Biological Signalling Studies BIOSS, University of Freiburg, Freiburg, Germany. .,Comprehensive Cancer Centre Freiburg, University of Freiburg, Freiburg, Germany. .,DKTK Partner Site Freiburg and DKFZ, Heidelberg, Germany.
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12
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Abstract
Cluster of differentiation 8 (CD8) is a cell surface glycoprotein, which is expressed as 2 forms, αα homodimer or αβ heterodimer. Peptide-loaded major histocompatibility complex class I (pMHC-I) molecules are major ligands for both forms of CD8. CD8αβ is a coreceptor for the T cell receptor (TCR) and binds to the same cognate pMHC-I as the TCR, thus enabling or augmenting T cell responses. The function of CD8αα homodimers is largely unknown. While CD8αβ heterodimer is expressed exclusively on CD8+ T cells, the CD8αα homodimer is present in subsets of T cells and human natural killer (NK) cells. Here, we report that the CD8αα homodimer functions as a coreceptor for KIR3DL1, an inhibitory receptor of NK cells that is specific for certain MHC-I allotypes. CD8αα enhances binding of pMHC-I to KIR3DL1, increases KIR3DL1 clustering at the immunological synapse, and augments KIR3DL1-mediated inhibition of NK cell activation. Additionally, interactions between pMHC-I and CD8αα homodimers regulate KIR3DL1+ NK cell education. Together, these findings reveal another dimension to the modulation of NK cell activity.
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13
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Ellebrecht CT, Bhoj VG, Nace A, Choi EJ, Mao X, Cho MJ, Di Zenzo G, Lanzavecchia A, Seykora JT, Cotsarelis G, Milone MC, Payne AS. Reengineering chimeric antigen receptor T cells for targeted therapy of autoimmune disease. Science 2016; 353:179-84. [PMID: 27365313 PMCID: PMC5343513 DOI: 10.1126/science.aaf6756] [Citation(s) in RCA: 444] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/09/2016] [Indexed: 12/18/2022]
Abstract
Ideally, therapy for autoimmune diseases should eliminate pathogenic autoimmune cells while sparing protective immunity, but feasible strategies for such an approach have been elusive. Here, we show that in the antibody-mediated autoimmune disease pemphigus vulgaris (PV), autoantigen-based chimeric immunoreceptors can direct T cells to kill autoreactive B lymphocytes through the specificity of the B cell receptor (BCR). We engineered human T cells to express a chimeric autoantibody receptor (CAAR), consisting of the PV autoantigen, desmoglein (Dsg) 3, fused to CD137-CD3ζ signaling domains. Dsg3 CAAR-T cells exhibit specific cytotoxicity against cells expressing anti-Dsg3 BCRs in vitro and expand, persist, and specifically eliminate Dsg3-specific B cells in vivo. CAAR-T cells may provide an effective and universal strategy for specific targeting of autoreactive B cells in antibody-mediated autoimmune disease.
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Affiliation(s)
| | - Vijay G Bhoj
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arben Nace
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eun Jung Choi
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xuming Mao
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael Jeffrey Cho
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Giovanni Di Zenzo
- Laboratory of Molecular and Cellular Biology, Istituto Dermopatico dell'Immacolata (IDI-IRCCS), 00167 Rome, Italy
| | | | - John T Seykora
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - George Cotsarelis
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael C Milone
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Aimee S Payne
- Department of Dermatology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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14
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Abstract
Membranes protect cells from the surrounding environment but also provide a means for the optimization of processes such as metabolism, signalling, or mitogenesis. Membrane structure and function is determined by its molecular composition. How lipid species define membrane properties is discussed in this introductory chapter.
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Affiliation(s)
- Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry, The Academy of Sciences of the Czech Republic, Dolejškova 2155/3, 182 23, Prague 8, Czech Republic,
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15
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Lavieu G, Zheng H, Rothman JE. Stapled Golgi cisternae remain in place as cargo passes through the stack. eLife 2013; 2:e00558. [PMID: 23755362 PMCID: PMC3673335 DOI: 10.7554/elife.00558] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 04/26/2013] [Indexed: 12/16/2022] Open
Abstract
We have designed a membrane ‘staple’, which consists of membrane-anchored repeats of the trans-aggregating FM domain that face the lumen of the secretory pathway. In the presence of the disaggregating drug these proteins transit the secretory pathway. When the drug is removed these proteins form electron-dense plaques which we term staples. Unexpectedly, when initially positioned within the cis-Golgi, staples remained at the cis face of the Golgi even after many hours. By contrast, soluble FM-aggregates transited the Golgi. Staples and soluble aggregates placed in cis-Golgi cisternae therefore have different fates. Whereas the membrane staples are located in the flattened, stacked central regions of the cisternae, the soluble aggregates are in the dilated rims. This suggests that while the cisternae are static on the time scale of protein traffic, the dilated rims are mobile and progress in the cis → trans direction via a mechanism that we term ‘Rim Progression’. DOI:http://dx.doi.org/10.7554/eLife.00558.001 Most plant and animal cells contain an organelle known as the Golgi apparatus, which consists of a series of four to six stacked cisternae. Almost all the proteins that are secreted from the cell, or targeted to its plasma membrane, transit through the Golgi. This process takes roughly 5–20 min. Although transport of proteins through the Golgi was first observed more than 50 years ago, it is still unclear exactly how this process occurs. One possibility is that proteins to be packaged move through the cisternae enclosed in vesicles, as if on a conveyor belt. Alternatively, the proteins themselves may remain stationary while the Golgi cisternae move over them. Now, Lavieu et al. provide evidence that the Golgi shows both mobile and static behaviour depending on the type and size of the cargo being processed. To distinguish between these two mechanisms, they created a new type of protein cargo—which they called a ‘staple’—that became fixed to the walls on each side of the cisternae and could not, therefore, move freely through the Golgi. They compared the processing of this protein to that of a more typical soluble protein cargo, which could move freely through the Golgi stack. Surprisingly, the Golgi processed these two types of cargo in very different ways. The staples remained embedded in the walls in the center of the cisternae, whereas the conventional soluble cargo was transported past the staples and collected at the edges of the cisternae, which are known as rims. These are wider than the center of the cisternae, and the staples are too narrow to span them. Lavieu et al. suggest that the Golgi cisternae can be divided into two functionally distinct domains: the centers of cisternae, which remain stationary, and the edges or rims, which can move. In addition to increasing our understanding of how proteins are prepared for transport inside cells, this new mechanism reconciles seemingly conflicting data by revealing that the Golgi can be both mobile and static. DOI:http://dx.doi.org/10.7554/eLife.00558.002
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Affiliation(s)
- Gregory Lavieu
- Department of Cell Biology , Yale University School of Medicine , New Haven , United States
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16
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The transmembrane domain of the adenovirus E3/19K protein acts as an endoplasmic reticulum retention signal and contributes to intracellular sequestration of major histocompatibility complex class I molecules. J Virol 2013; 87:6104-17. [PMID: 23514889 DOI: 10.1128/jvi.03391-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human adenovirus E3/19K protein is a type I transmembrane glycoprotein of the endoplasmic reticulum (ER) that abrogates cell surface transport of major histocompatibility complex class I (MHC-I) and MHC-I-related chain A and B (MICA/B) molecules. Previous data suggested that E3/19K comprises two functional modules: a luminal domain for interaction with MHC-I and MICA/B molecules and a dilysine motif in the cytoplasmic tail that confers retrieval from the Golgi apparatus back to the ER. This study was prompted by the unexpected phenotype of an E3/19K molecule that was largely retained intracellularly despite having a mutated ER retrieval motif. To identify additional structural determinants responsible for ER localization, chimeric molecules were generated containing the luminal E3/19K domain and the cytoplasmic and/or transmembrane domain (TMD) of the cell surface protein MHC-I K(d). These chimeras were analyzed for transport, cell surface expression, and impact on MHC-I and MICA/B downregulation. As with the retrieval mutant, replacement of the cytoplasmic tail of E3/19K allowed only limited transport of the chimera to the cell surface. Efficient cell surface expression was achieved only by additionally replacing the TMD of E3/19K with that of MHC-I, suggesting that the E3/19K TMD may confer static ER retention. This was verified by ER retention of an MHC-I K(d) molecule with the TMD replaced by that of E3/19K. Thus, we have identified the E3/19K TMD as a novel functional element that mediates static ER retention, thereby increasing the concentration of E3/19K in the ER. Remarkably, the ER retrieval signal alone, without the E3/19K TMD, did not mediate efficient HLA downregulation, even in the context of infection. This suggests that the TMD is required together with the ER retrieval function to ensure efficient ER localization and transport inhibition of MHC-I and MICA/B molecules.
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17
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Hansen JD, Farrugia TJ, Woodson J, Laing KJ. Description of an elasmobranch TCR coreceptor: CD8α from Rhinobatos productus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:452-460. [PMID: 21110999 DOI: 10.1016/j.dci.2010.11.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 11/18/2010] [Accepted: 11/18/2010] [Indexed: 05/30/2023]
Abstract
Cell-mediated immunity plays an essential role for the control and eradication of intracellular pathogens. To learn more about the evolutionary origins of the first signal (Signal 1) for T-cell activation, we cloned CD8α from an elasmobranch, Rhinobatos productus. Similar to full-length CD8α cDNAs from other vertebrates, Rhpr-CD8α (1800bp) encodes a 219 amino acid open reading frame composed of a signal peptide, an extracellular IgSF V domain and a stalk/hinge region followed by a well-conserved transmembrane domain and cytoplasmic tail. Overall, the mature Rhpr-CD8α protein (201 aa) displays ∼ 30% amino acid identity with mammalian CD8α including absolute conservation of cysteine residues involved in the IgSf V domain fold and dimerization of CD8αα and CD8αβ. One prominent feature is the absence of the LCK association motif (CXC) that is needed for achieving signal 1 in tetrapods. Both elasmobranch and teleost CD8α protein sequences possess a similar but distinctly different motif (CXH) in the cytoplasmic tail. The overall genomic structure of CD8α has been conserved during the course of vertebrate evolution both for the number of exons and phase of splicing. Finally, quantitative RTPCR demonstrated that elasmobranch CD8α is expressed in lymphoid-rich tissues similar to CD8 in other vertebrates. The results from this study indicate the existence of CD8 prior to the emergence of the gnathostomes (>450 MYA) while providing evidence that the canonical LCK association motif in mammals is likely a derived characteristic of tetrapod CD8α, suggesting potential differences for T-cell education and activation in the various gnathostomes.
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Affiliation(s)
- John D Hansen
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA.
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18
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Kang YJ, Wang X, Lin SJ, Hsu YM, Chang HC. An active CD8alpha/pMHCI interaction is required for CD8 single positive thymocyte differentiation. Eur J Immunol 2010; 40:836-48. [PMID: 19950178 DOI: 10.1002/eji.200939663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recognition of viral antigenic peptides bound to major histocompatibility complex class I molecules (MHCI) by TCR is critical for initiating the responses of CD8(+) T cells that ultimately lead to elimination of virus-infected cells. This antigen recognition is enhanced by the CD8 coreceptor through its interaction with the peptide-MHCI complexes (pMHCI). Mouse CD8alphabeta can form two different complexes with pMHCI via either the CD8alpha- or CD8beta-dominated interaction. To understand the functional significance of these complexes in vivo, we generated Tg mice carrying a variant CD8alphabeta (CD8alpha(m3)beta) capable of forming only the CD8beta-dominated CD8alphabeta/pMHCI complex. These mice show sub-optimal thymic differentiation with reduced populations of CD8(+) single-positive thymocytes. Tg CD8(+) T cells exhibit a compromised developmental capacity when competing with CD8(+) T cells from B6 mice in mixed bone marrow chimera experiments. However, once these CD8(+) T cells have emigrated to the peripheral lymphoid organs, they exhibit normal effector function against viral infection. Our observations indicate that, in addition to the CD8 activity conferred by CD8beta-dominated CD8alphabeta/pMHCI complexes, full thymocyte differentiation requires additional coreceptor activities conferred by CD8alphaalpha and/or CD8alphabeta with CD8alpha-dominated CD8/pMHCI complexes.
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Affiliation(s)
- Yoon-Joong Kang
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, USA
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19
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Induction of cortical endoplasmic reticulum by dimerization of a coatomer-binding peptide anchored to endoplasmic reticulum membranes. Proc Natl Acad Sci U S A 2010; 107:6876-81. [PMID: 20351264 DOI: 10.1073/pnas.1002536107] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cortical endoplasmic reticulum (cER) is a permanent feature of yeast cells but occurs transiently in most animal cell types. Ist2p is a transmembrane protein that permanently localizes to the cER in yeast. When Ist2 is expressed in mammalian cells, it induces abundant cER containing Ist2. Ist2 cytoplasmic C-terminal peptide is necessary and sufficient to induce cER. This peptide sequence resembles classic coat protein complex I (COPI) coatomer protein-binding KKXX signals, and indeed the dimerized peptide binds COPI in vitro. Controlled dimerization of this peptide induces cER in cells. RNA interference experiments confirm that coatomer is required for cER induction in vivo, as are microtubules and the microtubule plus-end binding protein EB1. We suggest that Ist2 dimerization triggers coatomer binding and clustering of this protein into domains that traffic at the microtubule growing plus-end to generate the cER beneath the plasma membrane. Sequences similar to the Ist2 lysine-rich tail are found in mammalian STIM proteins that reversibly induce the formation of cER under calcium control.
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20
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D'Angelo G, Prencipe L, Iodice L, Beznoussenko G, Savarese M, Marra P, Di Tullio G, Martire G, De Matteis MA, Bonatti S. GRASP65 and GRASP55 sequentially promote the transport of C-terminal valine-bearing cargos to and through the Golgi complex. J Biol Chem 2009; 284:34849-60. [PMID: 19840934 DOI: 10.1074/jbc.m109.068403] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Golgi matrix proteins GRASP65 and GRASP55 have recognized roles in maintaining the architecture of the Golgi complex, in mitotic progression and in unconventional protein secretion whereas, surprisingly, they have been shown to be dispensable for the transport of commonly used reporter cargo proteins along the secretory pathway. However, it is becoming increasingly clear that many trafficking machineries operate in a cargo-specific manner, thus we have investigated whether GRASPs may control the trafficking of selected classes of cargo. We have taken into consideration the C-terminal valine-bearing receptors CD8alpha and Frizzled4 that we show bind directly to the PSD95-DlgA-zo-1 (PDZ) domains of GRASP65 and GRASP55. We demonstrate that both GRASPs are needed sequentially for the efficient transport to and through the Golgi complex of these receptors, thus highlighting a novel role for the GRASPs in membrane trafficking. Our results open new perspectives for our understanding of the regulation of surface expression of a class of membrane proteins, and suggests the causal mechanisms of a dominant form of autosomal human familial exudative vitreoretinopathy that arises from the Frizzled4 mutation involving its C-terminal valine.
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Affiliation(s)
- Giovanni D'Angelo
- Department of Biochemistry and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
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21
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Park JH, Adoro S, Lucas PJ, Sarafova SD, Alag AS, Doan LL, Erman B, Liu X, Ellmeier W, Bosselut R, Feigenbaum L, Singer A. 'Coreceptor tuning': cytokine signals transcriptionally tailor CD8 coreceptor expression to the self-specificity of the TCR. Nat Immunol 2007; 8:1049-59. [PMID: 17873878 DOI: 10.1038/ni1512] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 08/16/2007] [Indexed: 02/06/2023]
Abstract
T cell immunity requires the long-term survival of T cells that are capable of recognizing self antigens but are not overtly autoreactive. How this balance is achieved remains incompletely understood. Here we identify a homeostatic mechanism that transcriptionally tailors CD8 coreceptor expression in individual CD8+ T cells to the self-specificity of their clonotypic T cell receptor (TCR). 'Coreceptor tuning' results from interplay between cytokine and TCR signals, such that signals from interleukin 7 and other common gamma-chain cytokines transcriptionally increase CD8 expression and thereby promote TCR engagement of self ligands, whereas TCR signals impair common gamma-chain cytokine signaling and thereby decrease CD8 expression. This dynamic interplay induces individual CD8+ T cells to express CD8 in quantities appropriate for the self-specificity of their TCR, promoting the engagement of self ligands, yet avoiding autoreactivity.
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Affiliation(s)
- Jung-Hyun Park
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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22
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Kaether C, Scheuermann J, Fassler M, Zilow S, Shirotani K, Valkova C, Novak B, Kacmar S, Steiner H, Haass C. Endoplasmic reticulum retention of the gamma-secretase complex component Pen2 by Rer1. EMBO Rep 2007; 8:743-8. [PMID: 17668005 PMCID: PMC1978084 DOI: 10.1038/sj.embor.7401027] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 06/01/2007] [Accepted: 06/04/2007] [Indexed: 11/09/2022] Open
Abstract
gamma-Secretase is involved in the production of amyloid beta-peptide, which is the principal component of amyloid plaques in the brains of patients with Alzheimer disease. gamma-Secretase is a complex composed of presenilin (PS), nicastrin, anterior pharynx-defective phenotype 1 (Aph1) and PS enhancer 2 (Pen2). We previously proposed a mechanism of complex assembly by which unassembled subunits are retained in the endoplasmic reticulum (ER) and only the fully assembled complex is exported from the ER. We have now identified Retention in endoplasmic reticulum 1 (Rer1) as a protein that is involved in the retention/retrieval of unassembled Pen2 to the ER. Direct binding of unassembled Pen2 to Rer1 is mediated by the first transmembrane domain of Pen2, and a conserved asparagine in this domain is required. Downregulation of Rer1 leads to increased surface localization of Pen2, whereas overexpression of Rer1 stabilizes unassembled Pen2. To our knowledge, Rer1 is the first identified interaction partner of mammalian transmembrane-based retention/retrieval signals.
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Affiliation(s)
- Christoph Kaether
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Center For Integrated Protein Science Munich and Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München 80336, Germany.
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23
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Iwahashi J, Hamada N, Watanabe H. Two hydrophobic segments of the RTN1 family determine the ER localization and retention. Biochem Biophys Res Commun 2007; 355:508-12. [PMID: 17303085 DOI: 10.1016/j.bbrc.2007.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
Reticulon (RTN) proteins are localized to the endoplasmic reticulum (ER), and are related to intracellular membrane trafficking, apoptosis, inhibiting axonal regeneration, and Alzheimer's disease. The RTN proteins are produced without an N-terminal signal peptide. Their C-terminal domain contains two long hydrophobic segments. We analyzed the ER localization signal of human RTN1-A. Mutant proteins lacking the first (39 residues) or second (36 residues) hydrophobic segment showed ER localization. On the other hand, the mutant lacking both hydrophobic segments was cytosolic. Enhanced green fluorescent protein (EGFP) tagged with the first or second hydrophobic segment of RTN1-A was localized to the ER. These results suggest that each hydrophobic segment determines the ER localization. In addition, EGFP tagged with the truncated form of the first hydrophobic segment exhibited the localization to the Golgi rather than the ER. This suggests that the length of the hydrophobic segment contributes to the ER retention of RTN1-A.
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Affiliation(s)
- Jun Iwahashi
- Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan.
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24
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Cauvi DM, Tian X, von Loehneysen K, Robertson MW. Transport of the IgE receptor alpha-chain is controlled by a multicomponent intracellular retention signal. J Biol Chem 2006; 281:10448-60. [PMID: 16459334 DOI: 10.1074/jbc.m510751200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human high affinity IgE receptor (FcepsilonRI) is a central component of the allergic response and is expressed as either a trimeric alphagamma2 or tetrameric alphabetagamma2 complex. It has been previously described that the cytoplasmic domain (CD) of the alpha-chain carries a dilysine motif at positions -3/-7 from the C terminus that functions in intracellular retention prior to assembly with other FcepsilonRI subunits. In this report we have further explored the role of the -3/-7 dilysine signal in controlling steady-state alpha-chain transport by mutational analysis and found little surface expression of a -3/-7 dialanine alpha-chain mutant but significant Golgi localization. We compared the transport properties of a series of alpha-chain cytoplasmic domain truncation mutants and observed that truncation mutants lacking 23 or more C-terminal residues showed a dramatic increase in steady-state transport suggesting a role for the membrane-proximal CD sequence in alpha-chain retention. By performing alanine-scanning mutagenesis we identified a dilysine sequence (Lys(212)-Lys(216)) proximal to the transmembrane domain (TMD) that is important for both alpha-chain cell-surface expression and intracellular stability. Furthermore, co-mutation of the Lys(212)-Lys(216) residues with the -3/-7 dilysine signal produced a dramatic increase in alpha-chain surface expression that was further increased by co-mutation of the lone charged residue (Asp(192)) in the TMD thereby defining three regions that function to regulate alpha-chain transport and in a highly synergistic manner.
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Affiliation(s)
- David M Cauvi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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25
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Chandele A, Kaech SM. Cutting edge: memory CD8 T cell maturation occurs independently of CD8alphaalpha. THE JOURNAL OF IMMUNOLOGY 2005; 175:5619-23. [PMID: 16237050 PMCID: PMC3245648 DOI: 10.4049/jimmunol.175.9.5619] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
As memory CD8 T cells form during acute viral infection, several changes in gene expression and function occur, but little is known about the control of this process. It was reported previously that the homodimer CD8alphaalpha was involved in generating IL-7Ralphahigh memory CD8 T cell precursors, and consequently, protective memory CD8 T cells did not form in animals significantly impaired in CD8alphaalpha expression (E8(I)-/- mice). However, the precise contribution of CD8alphaalpha to sustained IL-7Ralpha expression and other memory CD8 T cell-associated changes has not been investigated. We found that IL-7Ralpha expression and generation of memory CD8 T cells that protect against secondary viral infection was considerably normal in E8(I)-/- animals. Interestingly, virus-specific CD4 T cell responses were elevated, and the relative surface levels of CD8alphabeta in activated T cells were reduced in E8(I)-/- mice compared with wild-type animals. Our results indicate that memory CD8 T cell development can occur independently of CD8alphaalpha.
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Affiliation(s)
| | - Susan M. Kaech
- Address correspondence and reprint requests to Dr. Susan M. Kaech, 300 Cedar Street, TAC S641B, Yale University School of Medicine, P.O. Box 208011, New Haven, CT 06520.
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26
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Kaether C, Capell A, Edbauer D, Winkler E, Novak B, Steiner H, Haass C. The presenilin C-terminus is required for ER-retention, nicastrin-binding and gamma-secretase activity. EMBO J 2004; 23:4738-48. [PMID: 15549135 PMCID: PMC535090 DOI: 10.1038/sj.emboj.7600478] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2004] [Accepted: 10/15/2004] [Indexed: 11/09/2022] Open
Abstract
gamma-Secretase is an intramembrane cleaving protease involved in Alzheimer's disease. gamma-Secretase occurs as a high molecular weight complex composed of presenilin (PS1/2), nicastrin (NCT), anterior pharynx-defective phenotype 1 and PS enhancer 2. Little is known about the cellular mechanisms of gamma-secretase assembly. Here we demonstrate that the cytoplasmic tail of PS1 fulfills several functions required for complex formation, retention of unincorporated PS1 and gamma-secretase activity. The very C-terminus interacts with the transmembrane domain of NCT and may penetrate into the membrane. Deletion of the last amino acid is sufficient to completely block gamma-secretase assembly and release of PS1 from the endoplasmic reticulum (ER). This suggests that unincorporated PS1 is actively retained within the ER. We identified a hydrophobic stretch of amino acids within the cytoplasmic tail of PS1 distinct from the NCT-binding site, which is required to retain unincorporated PS1 within the ER. Deletion of the retention signal results in the release of PS1 from the ER and the assembly of a nonfunctional gamma-secretase complex, suggesting that at least a part of the retention motif may also be required for the function of PS1.
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Affiliation(s)
- Christoph Kaether
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, Schillerstr. 44, 80336 München, Germany. Tel.: +49 89 218075 471/472; Fax: +49 89 218075 415; E-mail:
| | - Anja Capell
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
| | - Dieter Edbauer
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
| | - Edith Winkler
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
| | - Bozidar Novak
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
| | - Harald Steiner
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
| | - Christian Haass
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institute, Ludwig-Maximilians-Universität, München, Germany
- Laboratory for Alzheimer's and Parkinson's Disease Research, Department of Biochemistry, Adolf-Butenandt-Institut, Ludwig-Maximilians-Universität München, Schillerstr. 44, 80336 München, Germany. Tel.: +49 89 218075 471/472; Fax: +49 89 218075 415; E-mail:
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27
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Sato M, Sato K, Nakano A. Endoplasmic reticulum quality control of unassembled iron transporter depends on Rer1p-mediated retrieval from the golgi. Mol Biol Cell 2004; 15:1417-24. [PMID: 14699055 PMCID: PMC363159 DOI: 10.1091/mbc.e03-10-0765] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 12/02/2003] [Accepted: 12/02/2003] [Indexed: 11/11/2022] Open
Abstract
Endoplasmic reticulum (ER) quality control is a conserved process by which misfolded or unassembled proteins are selectively retained in the endoplasmic reticulum (ER). Failure in oligomerization of multisubunit membrane proteins is one of the events that triggers ER quality control. The transmembrane domains (TMDs) of unassembled subunits are determinants of ER retention in many cases, although the mechanism of the TMD-mediated sorting of unassembled subunits remains elusive. We studied a yeast iron transporter complex on the cell surface as a new model system for ER quality control. When Fet3p, a transmembrane subunit, is not assembled with the other membrane subunit, Ftr1p, unassembled Fet3p is exclusively localized to the ER at steady state. The TMD of Fet3p contains a determinant for this process. However, pulse-chase analysis and in vitro budding assays indicate that unassembled Fet3p rapidly escapes from the ER. Furthermore, Rer1p, a retrieval receptor for ER-resident membrane proteins in the Golgi, is responsible for the TMD-dependent ER retrieval of unassembled Fet3p. These findings provide clear evidence that the ER quality control of unassembled membrane proteins can be achieved by retrieval from the Golgi and that Rer1p serves as a specific sorting receptor in this process.
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Affiliation(s)
- Miyuki Sato
- Molecular Membrane Biology Laboratory, RIKEN Discovery Research Institute, Saitama 351-0198, Japan
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28
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Kienzle N, Baz A, Kelso A. Profiling the CD8lowphenotype, an alternative career choice for CD8 T cells during primary differentiation. Immunol Cell Biol 2004; 82:75-83. [PMID: 14984598 DOI: 10.1111/j.1440-1711.2004.01210.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A CD8+ T cell of naive phenotype has multiple career choices during its primary differentiation into an effector cell population. One of these career options is becoming a CD8low T cell. We have previously shown by in vitro studies that CD8low T cells have lost expression of CD8 surface protein and mRNA and are poorly cytolytic. In line with poor cytolytic function, CD8low T cells express low levels of perforin and granzyme B and C, mediators of the granule-exocytosis machinery. However, CD8low T cells express IFN-gamma and substantial amounts of IL-4, the signature cytokines of type 1 and type 2 T-cell polarization, respectively. Here, we argue that the CD8low phenotype is an alternative career choice for any naive CD8+ T cell during primary activation but that the probability of choosing this option is greatly enhanced by both IL-4 and strong activation conditions. CD8low T cells have downregulated CD8 alpha/beta heterodimers and no preferential CD8 alpha/alpha homodimer expression. As shown by anti-CD8 Ab blocking experiments, surface CD8 substantially contributes to the CD8 T cell's effector function (i.e. cytokine expression and cytolytic activity). The distinct effector profile of CD8low T cells gives an example of the complexity of different CD8 T cell careers during primary effector differentiation.
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Affiliation(s)
- Norbert Kienzle
- Cooperative Research Centre for Vaccine Technology, Queensland Institute of Medical Research, Brisbane 4006, Australia.
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29
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Masciopinto F, Campagnoli S, Abrignani S, Uematsu Y, Pileri P. The small extracellular loop of CD81 is necessary for optimal surface expression of the large loop, a putative HCV receptor. Virus Res 2001; 80:1-10. [PMID: 11597743 DOI: 10.1016/s0168-1702(01)00245-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human tetraspanin CD81 is a putative receptor for hepatitis C virus (HCV), because it has been shown to bind 'bona fide' HCV particles. CD81, as all tetraspanins, spans the membrane four times forming two extracellular loops: a small (SEL) and a large one (LEL). We have shown previously that a recombinant form of LEL is sufficient for binding HCV through the major envelope glycoprotein E2. The role of SEL in the CD81-HCV interaction was questioned. We found that transfectants expressing LEL alone bind the recombinant HCV-E2 protein at much lower levels than cells expressing the wild type CD81. And therefore whether SEL contributes to the CD81-HCV interaction or whether it influences the expression of LEL was examined. We have found that in the absence of SEL, LEL is expressed at significantly reduced levels on the cell surface because it is retained intracellularly, while HCV-E2 still binds LEL. Our data suggest that SEL of CD81 does not mediate interaction with HCV, but contributes to optimal cell surface expression of LEL by mediating translocation of the whole CD81 molecule to the cell surface.
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Affiliation(s)
- F Masciopinto
- Immunology Department, IRIS Research Institute, Chiron S.p.A., Via Fiorentina, 1 I-53100, Siena, Italy
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30
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Favreau C, Bastos R, Cartaud J, Courvalin JC, Mustonen P. Biochemical characterization of nuclear pore complex protein gp210 oligomers. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:3883-9. [PMID: 11453980 DOI: 10.1046/j.1432-1327.2001.02290.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The membrane-spanning glycoprotein gp210 is a major component of the nuclear pore complex. This nucleoporin contains a large cisternal N-terminal domain, a short C-terminal cytoplasmic tail, and a single transmembrane segment. We show here that dimers of native gp210 can be isolated from cell extracts by immunoprecipitation, and from purified rat liver nuclear envelopes by velocity sedimentation and gel filtration. Cross-linking of proteins in isolated membranes prior to solubilization dramatically increases the proportion of dimers. The dimers are SDS-resistant, as previously observed for some integral membrane proteins of cis-Golgi and plasma membrane proteins, including glycophorin A. Larger oligomers of gp210 can also be obtained by gel filtration and denaturing electrophoresis, but unlike the dimers are dissociated by reduction and heating in the presence of SDS. We propose that gp210 is organized into the pore membrane as a large array of gp210 dimers that may constitute a luminal submembranous protein skeleton.
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Affiliation(s)
- C Favreau
- Département de Biologie Cellulaire, Institut Jacques Monod, UMR 7592, CNRS/Université Paris 6 & 7, France
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31
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Miller MA, Steele RE. Lemon encodes an unusual receptor protein-tyrosine kinase expressed during gametogenesis in Hydra. Dev Biol 2000; 224:286-98. [PMID: 10926767 DOI: 10.1006/dbio.2000.9786] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In a screen for receptor protein-tyrosine kinase (RTK) genes expressed during gametogenesis in the cnidarian Hydra vulgaris, we isolated a cDNA encoding Lemon, an RTK with unusual features. Lemon is orthologous to Drosophila Dtrk, chicken Klg, and human colon carcinoma kinase-4. These genes constitute an RTK class characterized by a conserved transmembrane sequence, the presence of extracellular immunoglobulin-like repeats, and the absence of the DFG motif in the kinase domain. We provide evidence that Lemon is a component of an unusual RTK signal transduction mechanism that may involve transmembrane domain-mediated interactions and may not be dependent on its own catalytic activity. Lemon transcription is dynamically regulated in interstitial cells during asexual budding and gametogenesis. Transcriptional up-regulation occurs early in spermatogenesis and oogenesis concurrent with the local accumulation of interstitial cells in the body column of sexual polyps.
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Affiliation(s)
- M A Miller
- Department of Biological Chemistry and the Developmental Biology Center, University of California at Irvine, 92697, USA
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32
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Kim H, Park H, Montalvo L, Lennarz WJ. Studies on the role of the hydrophobic domain of Ost4p in interactions with other subunits of yeast oligosaccharyl transferase. Proc Natl Acad Sci U S A 2000; 97:1516-20. [PMID: 10677492 PMCID: PMC26466 DOI: 10.1073/pnas.040556797] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In the yeast, Saccharomyces cerevisiae, oligosaccharyl transferase (OT), which catalyzes the transfer of dolichol-linked oligosaccharide chains to nascent polypeptides in the endoplasmic reticulum, consists of nine nonidentical membrane protein subunits. Genetic and biochemical evidence indicated these nine proteins exist in three subcomplexes. Three of the OT subunits (Ost4p, Ost3p, and Stt3p) have been proposed to exist in one subcomplex. To investigate the interaction of these three membrane proteins, initially we carried out a mutational analysis of Ost4p, which is an extraordinarily small membrane protein containing only 36 amino acid residues. This analysis indicated that when single amino acid residues in a region close to the luminal face of the putative transmembrane domain of Ost4p were changed into an ionizable amino acid such as Lys or Asp, growth at 37 degrees C and OT activity measured in vitro were impaired. In addition, using immunoprecipitation techniques and Western blot analysis, we found that with these mutations the interaction between Ost4p, Ost3p, and Stt3p was disrupted. Introduction of Lys or Asp residues at other positions in the putative transmembrane domain or at the N or C terminus of Ost4p had no effect on disrupting subunit interactions or impairing the activity of OT. These findings suggest that a localized region of the putative transmembrane domain of Ost4p mediates in stabilization of the interaction with the two other OT subunits (Ost3p and Stt3p) in a subcomplex in the endoplasmic reticulum membrane.
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Affiliation(s)
- H Kim
- Department of Biochemistry, Institute for Cell and Developmental Biology, State University of New York, Stony Brook, NY 11794-5215, USA
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33
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Shenkman M, Ehrlich M, Lederkremer GZ. Masking of an endoplasmic reticulum retention signal by its presence in the two subunits of the asialoglycoprotein receptor. J Biol Chem 2000; 275:2845-51. [PMID: 10644751 DOI: 10.1074/jbc.275.4.2845] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human asialoglycoprotein receptor H1 and H2b subunits assemble into a hetero-oligomer that travels to the cell surface. The H2a variant on the other hand is a precursor of a cleaved soluble form that is secreted. Uncleaved H2a precursor molecules cannot exit the endoplasmic reticulum (ER), a lumenal juxtamembrane pentapeptide being responsible for their retention. Insertion of this pentapeptide into H1 (H1i5) causes its complete ER retention but not fast degradation as happens to H2a. Cotransfection of H2a elicited, by heterodimerization, the Golgi processing of H1i5 and its surface expression. This occurred to a much lesser extent by cotransfection of H2b. Likewise, coexpression of H1i5 and not H1 stabilized H2a and caused its export to the cell surface. Homodimerization of molecules containing the pentapeptide did not cancel the retention. Thus, only when the pentapeptide is present in both subunits is the ER retention efficiently abrogated. The results show the unexpected finding that identical ER retention signals present in two associated chains can mask and cancel each other's effect. This could have important implications as similar abrogation of ER retention of other proteins could eventually be obtained by engineering and coexpressing an associated protein containing the same retention signal.
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Affiliation(s)
- M Shenkman
- Department of Cell Research, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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34
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Devine L, Kieffer LJ, Aitken V, Kavathas PB. Human CD8 beta, but not mouse CD8 beta, can be expressed in the absence of CD8 alpha as a beta beta homodimer. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:833-8. [PMID: 10623829 DOI: 10.4049/jimmunol.164.2.833] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The T cell coreceptor CD8 exists on mature T cells as disulfide-linked homodimers of CD8 alpha polypeptide chains and heterodimers of CD8 alpha- and CD8 beta-chains. The function of the CD8 alpha-chain for binding to MHC class I and associating with the tyrosine kinase p56lck was demonstrated with CD8 alpha alpha homodimers. CD8 alpha beta functions as a better coreceptor, but the actual function of CD8 beta is less clear. Addressing this issue has been hampered by the apparent inability of CD8 beta to be expressed without CD8 alpha. This study demonstrates that human, but not mouse, CD8 beta can be expressed on the cell surface without CD8 alpha in both transfected COS-7 cells and murine lymphocytes. By creating chimeric proteins, we show that the murine Ig domain of CD8 beta is responsible for the lack of expression of murine CD8 beta beta dimers. In contrast to CD8 alpha alpha, CD8 beta beta is unable to bind MHC class I in a cell-cell adhesion assay. Detection of this form of CD8 should facilitate studies on the function of the CD8 beta-chain and indicates that caution should be used when interpreting studies on CD8 function using chimeric protein with the murine CD8 beta beta Ig domain. In addition, we demonstrate that the Ig domains of CD8 alpha are also involved in controlling the ability of CD8 to be expressed. Mutation of B- and F-strand cysteine residues in CD8 alpha reduced the ability of the protein to fold properly and, therefore, to be expressed.
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Affiliation(s)
- L Devine
- Department of Laboratory Medicine, Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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35
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Letourneur F, Cosson P. Targeting to the endoplasmic reticulum in yeast cells by determinants present in transmembrane domains. J Biol Chem 1998; 273:33273-8. [PMID: 9837899 DOI: 10.1074/jbc.273.50.33273] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The transmembrane domains (TMDs) of many type I integral membrane proteins contain determinants that cause localization in the endoplasmic reticulum (ER) in mammalian cells by an unknown mechanism. Here we show that the yeast ER localization machinery recognizes determinants in TMDs that are very similar to those identified previously in mammalian cells. These determinants are recognized in post-ER compartments and recycled back to the ER, thus acting as ER retrieval signals. Moreover determinants in TMDs are inefficiently sorted in several previously characterized yeast mutants with defects in the ER retrieval machinery. Similar ER retrieval signals are also recognized in the TMDs of polytopic integral membrane proteins, apparently by the same sorting machinery. The isolation of new mutants defective in sorting of membrane determinants might provide a better understanding of the molecular mechanisms involved in this process.
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Affiliation(s)
- F Letourneur
- Institut de Biologie et de Chimie des Protéines, 69367 Lyon, France
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36
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Abstract
Coatomer-mediated sorting of proteins is based on the physical interaction between coatomer (COP1) and targeting motifs found in the cytoplasmic domains of membrane proteins. For example, binding of COP1 to dilysine (KKXX) motifs induces specific retrieval of tagged proteins from the Golgi back to the endoplasmic reticulum (ER). Making use of the two-hybrid system, we characterized a new sequence (deltaL) which interacts specifically with the delta-COP subunit of the COP1 complex. Transfer of deltaL to the cytoplasmic domain of a reporter membrane protein resulted in its localization in the ER, in yeast and mammalian cells. This was due to continuous retrieval of tagged proteins from the Golgi back to the ER, in a manner similar to the ER retrieval of KKXX-tagged proteins. Extensive mutagenesis of deltaL identified an aromatic residue as a critical determinant of the interaction with COP1. Similar COP1-binding motifs containing an essential aromatic residue were identified in the cytoplasmic domain of an ER-resident protein, Sec71p, and in an ER retention motif previously characterized in the CD3epsilon chain of the T-cell receptor. These results emphasize the role of the COP1 complex in retrograde Golgi-to-ER transport and highlight its functional similarity with clathrin-adaptor complexes.
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Affiliation(s)
- P Cosson
- Centre Médical Universitaire, Département de Morphologie, Genève, Switzerland
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37
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Ponimaskin E, Schmidt MF. Domain-structure of cytoplasmic border region is main determinant for palmitoylation of influenza virus hemagglutinin (H7). Virology 1998; 249:325-35. [PMID: 9791024 DOI: 10.1006/viro.1998.9303] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have shown previously that the length of cytoplasmic tails influences the selection of lipid substrates for palmitoylation of influenza viral hemagglutinin esterase fusion (HEF) and hemagglutinin (HA) glycoproteins [Veit et al. (1996) Biochem. J. 318, 163-172; Reverey et al. (1996) J. Biol. Chem. 271, 23607-23610]. Using a series of new chimeric mutant proteins derived from acylated influenza virus HA (subtype H7) and from nonacylated Sendai virus fusion protein (F, strain Z), we report here that palmitoylation levels depend on the type of transmembrane or cytoplasmic domain, or both, present in the expression products and that cysteine residues placed close to the cytoplasmic membrane border are not sufficient for acylation. By inserting stretches of the HA transmembrane domain into a nonacylated mutant of Sendai F (FCys), we induce palmitoylation after expression in CV.1 cells, and the level of fatty acid transfer increases with the length of the HA-derived insert. A five-amino-acid shift of the HA transmembrane domain severely augments fatty acid transfer. Our data suggest that the influenza virus HA contains complex conformational signals for palmitoylation that are mainly located within the transmembrane domain but also involve the C-tail region, whereas the extracellular (luminal) domain has only marginal influence on palmitoylation.
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Affiliation(s)
- E Ponimaskin
- Institut für Immunologie und Molekularbiologie, Fachbereich Veterinärmedizin der Freien Universität Berlin, Luisenstrasse 56, Berlin, D-10117, Germany
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38
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Fujiwara H, Hanissian SH, Tsytsykova A, Geha RS. Homodimerization of the human interleukin 4 receptor alpha chain induces Cepsilon germline transcripts in B cells in the absence of the interleukin 2 receptor gamma chain. Proc Natl Acad Sci U S A 1997; 94:5866-71. [PMID: 9159166 PMCID: PMC20872 DOI: 10.1073/pnas.94.11.5866] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The cytokines interleukin (IL)-4 and IL-13 play a critical role in inducing Cepsilon germline transcripts and IgE isotype switching in human B cells. The IL-4 receptor (IL-4R) in B cells is composed of two chains, the IL-4-binding IL-4Ralpha chain, which is shared with the IL-13R, and the IL-2Rgamma (gammac) chain, which is shared with IL-7R, IL-9R, and IL-15R. IL-4 induces Cepsilon germline transcripts and IgE isotype switching in B cells from patients with gammac chain deficiency. Induction of Cepsilon germline transcripts by IL-4 in B cells that lack the gammac chain may involve signaling via the IL-13R. Alternatively, the IL-4Ralpha chain may transduce intracellular signals that lead to Cepsilon gene transcription independently of its association with other chains. We show that ligand-induced homodimerization of chimeric surface receptors consisting of the extracellular and transmembrane domains of the erythropoietin receptor and of the intracellular domain of IL-4Ralpha induces Janus kinase 1 (Jak1) activation, STAT6 activation, and Cepsilon germline transcripts in human B cell line BJAB. Disruption of the Jak1-binding proline-rich Box1 region of IL-4Ralpha abolished signaling by this chimeric receptor. Furthermore, B cells transfected with a chimeric CD8alpha/IL-4Ralpha receptor, which is expressed on the cell surface as a homodimer, constitutively expressed Cepsilon germline transcripts. These results suggest that homodimerization of the IL-4Ralpha chain is sufficient to transduce Jak1-dependent intracellular signals that lead to IgE isotype switching.
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MESH Headings
- Animals
- Antigens, CD/biosynthesis
- Antigens, CD/chemistry
- B-Lymphocytes/drug effects
- B-Lymphocytes/immunology
- B-Lymphocytes/physiology
- Burkitt Lymphoma
- CD8 Antigens/biosynthesis
- Dimerization
- Enzyme Activation
- Erythropoietin/pharmacology
- Humans
- Interleukin-4/pharmacology
- Macromolecular Substances
- Mice
- Receptors, Erythropoietin/biosynthesis
- Receptors, Interleukin/biosynthesis
- Receptors, Interleukin/chemistry
- Receptors, Interleukin-2/biosynthesis
- Receptors, Interleukin-2/chemistry
- Receptors, Interleukin-4
- Recombinant Fusion Proteins/biosynthesis
- STAT6 Transcription Factor
- Trans-Activators/biosynthesis
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- H Fujiwara
- Division of Immunology, Children's Hospital, and Department of Pediatrics, Harvard Medical School, Enders 8th Floor, 300 Longwood Avenue, Boston, MA 02115-5747, USA
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39
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Affiliation(s)
- J M Blechman
- Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel
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40
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Abstract
The membrane-spanning portions of many integral membrane proteins consist of one or a number of transmembrane α-helices, which are expected to be independently stable on thermodynamic grounds. Side-by-side interactions between these transmembrane α-helices are important in the folding and assembly of such integral membrane proteins and their complexes. In considering the contribution of these helix–helix interactions to membrane protein folding and oligomerization, a distinction between the energetics and specificity should be recognized. A number of contributions to the energetics of transmembrane helix association within the lipid bilayer will be relatively non-specific, including those resulting from charge–charge interactions and lipid–packing effects. Specificity (and part of the energy) in transmembrane α-helix association, however, appears to rely mainly upon a detailed stereochemical fit between sets of dynamically accessible states of particular helices. In some cases, these interactions are mediated in part by prosthetic groups.
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Affiliation(s)
- M A Lemmon
- Department of Pharmacology, New York University Medical Center, NY 10016
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