Interleukin-17A (IL-17A) is a key mediator of protective immunity to yeast and bacterial infections but also drives the pathogenesis of several autoimmune diseases, such as psoriasis or psoriatic arthritis. Here we show that the tetra-transmembrane protein CMTM4 is a subunit of the IL-17 receptor (IL-17R). CMTM4 constitutively associated with IL-17R subunit C to mediate its stability, glycosylation and plasma membrane localization. Both mouse and human cell lines deficient in CMTM4 were largely unresponsive to IL-17A, due to their inability to assemble the IL-17R signaling complex. Accordingly, CMTM4-deficient mice had a severe defect in the recruitment of immune cells following IL-17A administration and were largely resistant to experimental psoriasis, but not to experimental autoimmune encephalomyelitis. Collectively, our data identified CMTM4 as an essential component of IL-17R and a potential therapeutic target for treating IL-17-mediated autoimmune diseases.

• MeSH
• encefalomyelitida autoimunitní experimentální * genetika   MeSH
• interleukin-17 metabolismus   MeSH
• lidé MeSH
• myši MeSH
• proteiny obsahující MARVEL doménu genetika   MeSH
• psoriatická artritida * MeSH
• psoriáza * MeSH
• receptory interleukinu-17 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Bardet-Biedl syndrome (BBS) is a pleiotropic ciliopathy caused by dysfunction of primary cilia. More than half of BBS patients carry mutations in one of eight genes encoding for subunits of a protein complex, the BBSome, which mediates trafficking of ciliary cargoes. In this study, we elucidated the mechanisms of the BBSome assembly in living cells and how this process is spatially regulated. We generated a large library of human cell lines deficient in a particular BBSome subunit and expressing another subunit tagged with a fluorescent protein. We analyzed these cell lines utilizing biochemical assays, conventional and expansion microscopy, and quantitative fluorescence microscopy techniques: fluorescence recovery after photobleaching and fluorescence correlation spectroscopy. Our data revealed that the BBSome formation is a sequential process. We show that the pre-BBSome is nucleated by BBS4 and assembled at pericentriolar satellites, followed by the translocation of the BBSome into the ciliary base mediated by BBS1. Our results provide a framework for elucidating how BBS-causative mutations interfere with the biogenesis of the BBSome.

• MeSH
• Bardetův-Biedlův syndrom genetika   metabolismus   patologie   MeSH
• buněčné linie MeSH
• cilie metabolismus   MeSH
• CRISPR-Cas systémy genetika   MeSH
• cytoplazma metabolismus   MeSH
• editace genu MeSH
• fluorescenční mikroskopie MeSH
• FRAP MeSH
• lidé MeSH
• mutace MeSH
• podjednotky proteinů genetika   metabolismus   MeSH
• proteiny asociované s mikrotubuly nedostatek   genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

IL-17 mediates immune protection from fungi and bacteria, as well as it promotes autoimmune pathologies. However, the regulation of the signal transduction from the IL-17 receptor (IL-17R) remained elusive. We developed a novel mass spectrometry-based approach to identify components of the IL-17R complex followed by analysis of their roles using reverse genetics. Besides the identification of linear ubiquitin chain assembly complex (LUBAC) as an important signal transducing component of IL-17R, we established that IL-17 signaling is regulated by a robust negative feedback loop mediated by TBK1 and IKKε. These kinases terminate IL-17 signaling by phosphorylating the adaptor ACT1 leading to the release of the essential ubiquitin ligase TRAF6 from the complex. NEMO recruits both kinases to the IL-17R complex, documenting that NEMO has an unprecedented negative function in IL-17 signaling, distinct from its role in NF-κB activation. Our study provides a comprehensive view of the molecular events of the IL-17 signal transduction and its regulation.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• kinasa I-kappa B genetika   metabolismus   MeSH
• lidé MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• receptory interleukinu-17 genetika   metabolismus   MeSH
• signální transdukce * MeSH
• zpětná vazba fyziologická * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The linear-ubiquitin chain assembly complex (LUBAC) modulates signalling via various immune receptors. In tumour necrosis factor (TNF) signalling, linear (also known as M1) ubiquitin enables full gene activation and prevents cell death. However, the mechanisms underlying cell death prevention remain ill-defined. Here, we show that LUBAC activity enables TBK1 and IKKε recruitment to and activation at the TNF receptor 1 signalling complex (TNFR1-SC). While exerting only limited effects on TNF-induced gene activation, TBK1 and IKKε are essential to prevent TNF-induced cell death. Mechanistically, TBK1 and IKKε phosphorylate the kinase RIPK1 in the TNFR1-SC, thereby preventing RIPK1-dependent cell death. This activity is essential in vivo, as it prevents TNF-induced lethal shock. Strikingly, NEMO (also known as IKKγ), which mostly, but not exclusively, binds the TNFR1-SC via M1 ubiquitin, mediates the recruitment of the adaptors TANK and NAP1 (also known as AZI2). TANK is constitutively associated with both TBK1 and IKKε, while NAP1 is associated with TBK1. We discovered a previously unrecognized cell death checkpoint that is mediated by TBK1 and IKKε, and uncovered an essential survival function for NEMO, whereby it enables the recruitment and activation of these non-canonical IKKs to prevent TNF-induced cell death.

• MeSH
• buněčná smrt účinky léků   MeSH
• buňky A549 MeSH
• fosforylace účinky léků   MeSH
• HeLa buňky MeSH
• kinasa I-kappa B metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• myši knockoutované MeSH
• protein-serin-threoninkinasy interagující s receptory metabolismus   MeSH
• protein-serin-threoninkinasy metabolismus   MeSH
• receptory TNF - typ I metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• TNF-alfa farmakologie   MeSH
• ubikvitinace účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Virtual memory T cells are foreign antigen-inexperienced T cells that have acquired memory-like phenotype and constitute 10-20% of all peripheral CD8+ T cells in mice. Their origin, biological roles, and relationship to naïve and foreign antigen-experienced memory T cells are incompletely understood. By analyzing T-cell receptor repertoires and using retrogenic monoclonal T-cell populations, we demonstrate that the virtual memory T-cell formation is a so far unappreciated cell fate decision checkpoint. We describe two molecular mechanisms driving the formation of virtual memory T cells. First, virtual memory T cells originate exclusively from strongly self-reactive T cells. Second, the stoichiometry of the CD8 interaction with Lck regulates the size of the virtual memory T-cell compartment via modulating the self-reactivity of individual T cells. Although virtual memory T cells descend from the highly self-reactive clones and acquire a partial memory program, they are not more potent in inducing experimental autoimmune diabetes than naïve T cells. These data underline the importance of the variable level of self-reactivity in polyclonal T cells for the generation of functional T-cell diversity.

• MeSH
• buněčná diferenciace * MeSH
• CD8-pozitivní T-lymfocyty imunologie   MeSH
• homeostáza MeSH
• imunologická paměť * MeSH
• myši MeSH
• receptory antigenů T-buněk analýza   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Transmembrane adaptor proteins (TRAPs) are structurally related proteins that have no enzymatic function, but enable inducible recruitment of effector molecules to the plasma membrane, usually in a phosphorylation dependent manner. Numerous surface receptors employ TRAPs for either propagation or negative regulation of the signal transduction. Several TRAPs (LAT, NTAL, PAG, LIME, PRR7, SCIMP, LST1/A, and putatively GAPT) are known to be palmitoylated that could facilitate their localization in lipid rafts or tetraspanin enriched microdomains. This review summarizes expression patterns, binding partners, signaling pathways, and biological functions of particular palmitoylated TRAPs with an emphasis on the three most recently discovered members, PRR7, SCIMP, and LST1/A. Moreover, we discuss in silico methodology used for discovery of new family members, nature of their binding partners, and microdomain localization.

• MeSH
• adaptorové proteiny signální transdukční metabolismus   MeSH
• leukocyty metabolismus   fyziologie   MeSH
• lidé MeSH
• lipoylace MeSH
• membránové mikrodomény metabolismus   MeSH
• membránové proteiny metabolismus   MeSH
• signální transdukce * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

When a BCR on a mature B cell is engaged by its ligand, the cell becomes activated, and the Ab-mediated immune response can be triggered. The initiation of BCR signaling is orchestrated by kinases of the Src and Syk families. However, the proximal BCR-induced phosphorylation remains incompletely understood. According to a model of sequential activation of kinases, Syk acts downstream of Src family kinases (SFKs). In addition, signaling independent of SFKs and initiated by Syk has been proposed. Both hypotheses lack sufficient evidence from relevant B cell models, mainly because of the redundancy of Src family members and the importance of BCR signaling for B cell development. We addressed this issue by analyzing controlled BCR triggering ex vivo on primary murine B cells and on murine and chicken B cell lines. Chemical and Csk-based genetic inhibitor treatments revealed that SFKs are required for signal initiation and Syk activation. In addition, ligand and anti-BCR Ab-induced signaling differ in their sensitivity to the inhibition of SFKs.

• MeSH
• aktivace enzymů imunologie   MeSH
• buněčné linie MeSH
• intracelulární signální peptidy a proteiny metabolismus   fyziologie   MeSH
• kultivované buňky MeSH
• kur domácí MeSH
• modely u zvířat MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• receptory antigenů B-buněk metabolismus   fyziologie   MeSH
• receptory pre-B lymfocytů metabolismus   fyziologie   MeSH
• signální transdukce imunologie   MeSH
• skupina kinas odvozených od src-genu metabolismus   fyziologie   MeSH
• tyrosinkinasy metabolismus   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Transmembrane adaptor proteins are membrane-anchored proteins consisting of a short extracellular part, a transmembrane domain, and a cytoplasmic part with various protein-protein interaction motifs but lacking any enzymatic activity. They participate in the regulation of various signaling pathways by recruiting other proteins to the proximity of cellular membranes where the signaling is often initiated and propagated. In this work, we show that LST1/A, an incompletely characterized protein encoded by MHCIII locus, is a palmitoylated transmembrane adaptor protein. It is expressed specifically in leukocytes of the myeloid lineage, where it localizes to the tetraspanin-enriched microdomains. In addition, it binds SHP-1 and SHP-2 phosphatases in a phosphotyrosine-dependent manner, facilitating their recruitment to the plasma membrane. These data suggest a role for LST1/A in negative regulation of signal propagation.

• MeSH
• buněčná membrána metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• hlavní histokompatibilní komplex fyziologie   MeSH
• Jurkat buňky MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• myeloidní buňky cytologie   metabolismus   MeSH
• plakiny metabolismus   MeSH
• primární buněčná kultura MeSH
• pseudopodia metabolismus   MeSH
• sekvence aminokyselin MeSH
• signální transdukce fyziologie   MeSH
• terciární struktura proteinů fyziologie   MeSH
• transport proteinů fyziologie   MeSH
• tyrosinfosfatasa nereceptorového typu 11 metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 6 metabolismus   MeSH
• U937 buňky MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Formation of the immunological synapse between an antigen-presenting cell (APC) and a T cell leads to signal generation in both cells involved. In T cells, the lipid raft-associated transmembrane adaptor protein LAT plays a central role. Its phosphorylation is a crucial step in signal propagation, including the calcium response and mitogen-activated protein kinase activation, and largely depends on its association with the SLP76 adaptor protein. Here we report the discovery of a new palmitoylated transmembrane adaptor protein, termed SCIMP. SCIMP is expressed in B cells and other professional APCs and is localized in the immunological synapse due to its association with tetraspanin-enriched microdomains. In B cells, it is constitutively associated with Lyn kinase and becomes tyrosine phosphorylated after major histocompatibility complex type II (MHC-II) stimulation. When phosphorylated, SCIMP binds to the SLP65 adaptor protein and also to the inhibitory kinase Csk. While the association with SLP65 initiates the downstream signaling cascades, Csk binding functions as a negative regulatory loop. The results suggest that SCIMP is involved in signal transduction after MHC-II stimulation and therefore serves as a regulator of antigen presentation and other APC functions.

• MeSH
• adaptorové proteiny signální transdukční chemie   metabolismus   MeSH
• aktivace lymfocytů MeSH
• antigen prezentující buňky imunologie   MeSH
• B-lymfocyty imunologie   metabolismus   MeSH
• fosfoproteiny metabolismus   MeSH
• HEK293 buňky MeSH
• histokompatibilita - antigeny třídy II imunologie   metabolismus   MeSH
• imunologické synapse chemie   MeSH
• lidé MeSH
• malá interferující RNA MeSH
• membránové mikrodomény chemie   metabolismus   MeSH
• membránové proteiny chemie   genetika   imunologie   metabolismus   MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• molekulární sekvence - údaje MeSH
• prezentace antigenu MeSH
• RNA interference MeSH
• sekvence aminokyselin MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu metabolismus   MeSH
• src homologní domény MeSH
• T-lymfocyty imunologie   MeSH
• tyrosinkinasy chemie   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

CD148 is a receptor-like protein-tyrosine phosphatase known to inhibit transduction of mitogenic signals in non-hematopoietic cells. Similarly, in the hematopoietic lineage, CD148 inhibited signal transduction downstream of T cell receptor. However, it also augmented immunoreceptor signaling in B cells and macrophages via dephosphorylating C-terminal tyrosine of Src family kinases (SFK). Accordingly, endogenous CD148 compensated for the loss of the main SFK activator CD45 in murine B cells and macrophages but not in T cells. Hypothetical explanations for the difference between T cells and other leukocyte lineages include the inability of CD148 to dephosphorylate a specific set of SFKs involved in T cell activation or the lack of CD148 expression during critical stages of T cell development. Here we describe striking differences in CD148 expression between human and murine thymocyte subsets, the only unifying feature being the absence of CD148 during the positive selection when the major developmental block occurs under CD45 deficiency. Moreover, we demonstrate that similar to CD45, CD148 has both activating and inhibitory effects on the SFKs involved in TCR signaling. However, in the absence of CD45, activating effects prevail, resulting in functional complementation of CD45 deficiency in human T cell lines. Importantly, this is independent of the tyrosines in the CD148 C-terminal tail, contradicting the recently proposed phosphotyrosine displacement model as a mechanism of SFK activation by CD148. Collectively, our data suggest that differential effects of CD148 in T cells and other leukocyte subsets cannot be explained by the CD148 inability to activate T cell SFKs but rather by its dual inhibitory/activatory function and specific expression pattern.

• MeSH
• adaptorové proteiny signální transdukční metabolismus   MeSH
• aktivace enzymů MeSH
• antigeny CD45 nedostatek   MeSH
• fosfolipasa C gama metabolismus   MeSH
• fosforylace MeSH
• hematopoetické kmenové buňky cytologie   enzymologie   metabolismus   MeSH
• Jurkat buňky MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• myši MeSH
• receptory antigenů T-buněk imunologie   metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu chemie   metabolismus   MeSH
• T-lymfocyty cytologie   enzymologie   metabolismus   MeSH
• terciární struktura proteinů MeSH
• thymus cytologie   MeSH
• tyrosin metabolismus   MeSH
• tyrosinfosfatasy receptorového typu, třída 3 chemie   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH