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Roncagalli R, Cucchetti M, Jarmuzynski N, Grégoire C, Bergot E, Audebert S, Baudelet E, Menoita MG, Joachim A, Durand S, Suchanek M, Fiore F, Zhang L, Liang Y, Camoin L, Malissen M, Malissen B. The scaffolding function of the RLTPR protein explains its essential role for CD28 co-stimulation in mouse and human T cells. J Exp Med 2016; 213:2437-2457. [PMID: 27647348 PMCID: PMC5068240 DOI: 10.1084/jem.20160579] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 08/17/2016] [Indexed: 12/26/2022] Open
Abstract
In two complementary papers, Casanova, Malissen, and collaborators report the discovery of human RLTPR deficiency, the first primary immunodeficiency of the human CD28 pathway in T cells. Together, the two studies elucidate the largely (but not completely) overlapping roles of RLTPR in CD28 signaling in T and B cells of humans and mice. The RLTPR cytosolic protein, also known as CARMIL2, is essential for CD28 co-stimulation in mice, but its importance in human T cells and mode of action remain elusive. Here, using affinity purification followed by mass spectrometry analysis, we showed that RLTPR acts as a scaffold, bridging CD28 to the CARD11/CARMA1 cytosolic adaptor and to the NF-κB signaling pathway, and identified proteins not found before within the CD28 signaling pathway. We further demonstrated that RLTPR is essential for CD28 co-stimulation in human T cells and that its noncanonical pleckstrin-homology domain, leucine-rich repeat domain, and proline-rich region were mandatory for that task. Although RLTPR is thought to function as an actin-uncapping protein, this property was dispensable for CD28 co-stimulation in both mouse and human. Our findings suggest that the scaffolding role of RLTPR predominates during CD28 co-stimulation and underpins the similar function of RLTPR in human and mouse T cells. Along that line, the lack of functional RLTPR molecules impeded the differentiation toward Th1 and Th17 fates of both human and mouse CD4+ T cells. RLTPR was also expressed in both human and mouse B cells. In the mouse, RLTPR did not play, however, any detectable role in BCR-mediated signaling and T cell-independent B cell responses.
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Affiliation(s)
- Romain Roncagalli
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Margot Cucchetti
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Nicolas Jarmuzynski
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Claude Grégoire
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Elise Bergot
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Stéphane Audebert
- CRCM, Marseille Protéomique, Institut Paoli-Calmettes, Aix Marseille Université, INSERM, CNRS, 13009 Marseille, France
| | - Emilie Baudelet
- CRCM, Marseille Protéomique, Institut Paoli-Calmettes, Aix Marseille Université, INSERM, CNRS, 13009 Marseille, France
| | - Marisa Goncalves Menoita
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Anais Joachim
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Stéphane Durand
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | | | - Frédéric Fiore
- Centre d'Immunophénomique, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Lichen Zhang
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France.,School of Laboratory Medicine, Xinxiang Medical University, Xinxiang 453003, China
| | - Yinming Liang
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France.,School of Laboratory Medicine, Xinxiang Medical University, Xinxiang 453003, China
| | - Luc Camoin
- CRCM, Marseille Protéomique, Institut Paoli-Calmettes, Aix Marseille Université, INSERM, CNRS, 13009 Marseille, France
| | - Marie Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France .,Centre d'Immunophénomique, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
| | - Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France .,Centre d'Immunophénomique, Aix Marseille Université, INSERM, CNRS, 13288 Marseille, France
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Esensten JH, Helou YA, Chopra G, Weiss A, Bluestone JA. CD28 Costimulation: From Mechanism to Therapy. Immunity 2016; 44:973-88. [PMID: 27192564 PMCID: PMC4932896 DOI: 10.1016/j.immuni.2016.04.020] [Citation(s) in RCA: 526] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Indexed: 02/07/2023]
Abstract
Ligation of the CD28 receptor on T cells provides a critical second signal alongside T cell receptor (TCR) ligation for naive T cell activation. Here, we discuss the expression, structure, and biochemistry of CD28 and its ligands. CD28 signals play a key role in many T cell processes, including cytoskeletal remodeling, production of cytokines, survival, and differentiation. CD28 ligation leads to unique epigenetic, transcriptional, and post-translational changes in T cells that cannot be recapitulated by TCR ligation alone. We discuss the function of CD28 and its ligands in both effector and regulatory T cells. CD28 is critical for regulatory T cell survival and the maintenance of immune homeostasis. We outline the roles that CD28 and its family members play in human disease and we review the clinical efficacy of drugs that block CD28 ligands. Despite the centrality of CD28 and its family members and ligands to immune function, many aspects of CD28 biology remain unclear. Translation of a basic understanding of CD28 function into immunomodulatory therapeutics has been uneven, with both successes and failures. Such real-world results might stem from multiple factors, including complex receptor-ligand interactions among CD28 family members, differences between the mouse and human CD28 families, and cell-type specific roles of CD28 family members.
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Affiliation(s)
- Jonathan H Esensten
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA.
| | - Ynes A Helou
- Division of Rheumatology, Department of Medicine, Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, CA 94143, USA
| | - Gaurav Chopra
- Department of Chemistry, Purdue Center for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA
| | - Arthur Weiss
- Division of Rheumatology, Department of Medicine, Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA
| | - Jeffrey A Bluestone
- Diabetes Center and Department of Medicine, University of California, San Francisco, CA 94143, USA.
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Brzostek J, Gascoigne NRJ, Rybakin V. Cell Type-Specific Regulation of Immunological Synapse Dynamics by B7 Ligand Recognition. Front Immunol 2016; 7:24. [PMID: 26870040 PMCID: PMC4740375 DOI: 10.3389/fimmu.2016.00024] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/18/2016] [Indexed: 01/07/2023] Open
Abstract
B7 proteins CD80 (B7-1) and CD86 (B7-2) are expressed on most antigen-presenting cells and provide critical co-stimulatory or inhibitory input to T cells via their T-cell-expressed receptors: CD28 and CTLA-4. CD28 is expressed on effector T cells and regulatory T cells (Tregs), and CD28-dependent signals are required for optimum activation of effector T cell functions. CD28 ligation on effector T cells leads to formation of distinct molecular patterns and induction of cytoskeletal rearrangements at the immunological synapse (IS). CD28 plays a critical role in recruitment of protein kinase C (PKC)-θ to the effector T cell IS. CTLA-4 is constitutively expressed on the surface of Tregs, but it is expressed on effector T cells only after activation. As CTLA-4 binds to B7 proteins with significantly higher affinity than CD28, B7 ligand recognition by cells expressing both receptors leads to displacement of CD28 and PKC-θ from the IS. In Tregs, B7 ligand recognition leads to recruitment of CTLA-4 and PKC-η to the IS. CTLA-4 plays a role in regulation of T effector and Treg IS stability and cell motility. Due to their important roles in regulating T-cell-mediated responses, B7 receptors are emerging as important drug targets in oncology. In this review, we present an integrated summary of current knowledge about the role of B7 family receptor–ligand interactions in the regulation of spatial and temporal IS dynamics in effector and Tregs.
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Affiliation(s)
- Joanna Brzostek
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine and Immunology Programme, National University of Singapore , Singapore , Singapore
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine and Immunology Programme, National University of Singapore , Singapore , Singapore
| | - Vasily Rybakin
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine and Immunology Programme, National University of Singapore, Singapore, Singapore; Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
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Mutational Analysis of Glycogen Synthase Kinase 3β Protein Kinase Together with Kinome-Wide Binding and Stability Studies Suggests Context-Dependent Recognition of Kinases by the Chaperone Heat Shock Protein 90. Mol Cell Biol 2016; 36:1007-18. [PMID: 26755559 DOI: 10.1128/mcb.01045-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/05/2016] [Indexed: 11/20/2022] Open
Abstract
The heat shock protein 90 (HSP90) and cell division cycle 37 (CDC37) chaperones are key regulators of protein kinase folding and maturation. Recent evidence suggests that thermodynamic properties of kinases, rather than primary sequences, are recognized by the chaperones. In concordance, we observed a striking difference in HSP90 binding between wild-type (WT) and kinase-dead (KD) glycogen synthase kinase 3β (GSK3β) forms. Using model cell lines stably expressing these two GSK3β forms, we observed no interaction between WT GSK3β and HSP90, in stark contrast to KD GSK3β forming a stable complex with HSP90 at a 1:1 ratio. In a survey of 91 ectopically expressed kinases in DLD-1 cells, we compared two parameters to measure HSP90 dependency: static binding and kinase stability following HSP90 inhibition. We observed no correlation between HSP90 binding and reduced stability of a kinase after pharmacological inhibition of HSP90. We expanded our stability study to >50 endogenous kinases across four cell lines and demonstrated that HSP90 dependency is context dependent. These observations suggest that HSP90 binds to its kinase client in a particular conformation that we hypothesize to be associated with the nucleotide-processing cycle. Lastly, we performed proteomics profiling of kinases and phosphopeptides in DLD-1 cells to globally define the impact of HSP90 inhibition on the kinome.
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