Introduction: ZAP-70, a protein tyrosine kinase recruited to the T cell receptor (TCR), initiates a TCR signaling cascade upon antigen stimulation. Mutations in the gene cause a combined immunodeficiency characterized by low or absent CD8+ T cells and nonfunctional CD4+ T cells. Most deleterious missense mutations in patients are located in the kinase domain but the impact of mutations in the SH2 domains, regulating ZAP-70 recruitment to the TCR, are not well understood.
View Article and Find Full Text PDFAutoantibodies against CASPR2 (contactin-associated protein-like 2) have been linked to autoimmune limbic encephalitis that manifests with memory disorders and temporal lobe seizures. According to the growing number of data supporting a role for CASPR2 in neuronal excitability, CASPR2 forms a molecular complex with transient axonal glycoprotein-1 (TAG-1) and shaker-type voltage-gated potassium channels (Kv1.1 and Kv1.
View Article and Find Full Text PDFCD19 is a B cell-specific receptor that regulates the threshold of B cell receptor (BCR)-mediated cell proliferation. A CD47xCD19 bispecific antibody (biAb) was generated to target and deplete B cells via multiple antibody-mediated mechanisms. Interestingly, the biAb, constructed of a CD19 binding arm and a CD47 binding arm, inhibited BCR-mediated B-cell proliferation with an effect even more potent than a CD19 monoclonal antibody (mAb).
View Article and Find Full Text PDFAccumulating evidence has showed that anti-CASPR2 autoantibodies occur in a long list of neurological immune disorders including limbic encephalitis (LE). Belonging to the well-known neurexin superfamily, CASPR2 has been suggested to be a central node in the molecular networks controlling neurodevelopment. Distinct from other subfamilies in the neurexin superfamily, the CASPR subfamily features a unique discoidin (Disc) domain.
View Article and Find Full Text PDFContactin-associated protein-like 2 (CASPR2) is a cell adhesion protein of the neurexin family. Proteins of this family have been shown to play a role in the development of the nervous system, in synaptic functions, and in neurological diseases. Over recent years, CASPR2 function has gained an increasing interest as demonstrated by the growing number of publications.
View Article and Find Full Text PDFThe tyrosine kinases of the Syk family are essential components of the well-characterized immunoreceptor ITAM-based signaling pathway. However, ITAM-based signaling typically does not function in isolation. Instead, it is enmeshed in the molecular network controlling cellular adhesion and chemotaxis.
View Article and Find Full Text PDFCaspr2 and TAG-1 (also known as CNTNAP2 and CNTN2, respectively) are cell adhesion molecules (CAMs) associated with the voltage-gated potassium channels Kv1.1 and Kv1.2 (also known as KCNA1 and KCNA2, respectively) at regions controlling axonal excitability, namely, the axon initial segment (AIS) and juxtaparanodes of myelinated axons.
View Article and Find Full Text PDFImportance: Autoantibodies against contactin-associated protein-like 2 (CASPR2) are observed in several neurological syndromes, including neuromyotonia (NMT), Morvan syndrome (MoS), and limbic encephalitis.
Objective: To characterize the clinical and biological presentations of patients with anti-CASPR2 antibodies in the cerebrospinal fluid (CSF).
Design, Setting, And Participants: We conducted a retrospective cohort analysis of 18 patients who had anti-CASPR2 antibodies in their CSF between March 2009 and November 2015 at the Centre National de Référence pour les Syndromes Neurologiques Paranéoplasiques in Lyon, France.
In the hematopoietic system, Syk family tyrosine kinases are essential components of immunoreceptor ITAM-based signaling. While there is increasing data indicating the involvement of immunoreceptors in neural functions, the contribution of Syk kinases remains obscure. Previously, we identified phosphorylated forms of Syk kinases in specialized populations of migrating neurons or projecting axons.
View Article and Find Full Text PDFImmune signaling and neuroinflammatory mediators have recently emerged as influential variables that regulate neural precursor/stem cell (NPC) behavior and function. In this study, we investigated whether the signaling adaptor protein CD3ζ, a transmembrane protein involved in T cell differentiation and function and recently shown to regulate neuronal development in the central nervous system (CNS), may have a role in NPC differentiation. We analyzed the expression profile of CD3ζ in embryonic rat brain during neurogenic periods and in neurosphere-derived neural cells, and we investigated the action of CD3ζ on cell differentiation.
View Article and Find Full Text PDFAn increasing number of data involve immunoreceptors in brain development, synaptic plasticity and behavior. However it has yet to be determined whether these proteins in fact transmit an immunoreceptor-like signal in non-hematopoietic neuronal cells. The recruitment and activation of the Syk family tyrosine kinases, Syk and ZAP-70, being a critical step in this process, we conducted a thorough analysis of Syk/ZAP-70 expression pattern in nervous tissues.
View Article and Find Full Text PDFIn the central nervous system, collapsin response mediator protein 2 (CRMP2) is a transducer protein that supports the semaphorin-induced guidance of axons toward their cognate target. However, we previously showed that CRMP2 is also expressed in immune cells and plays a crucial role in T lymphocyte migration. Here we further investigated the molecular mechanisms underlying CRMP2 function in chemokine-directed T-cell motility.
View Article and Find Full Text PDFHIV efficiently spreads in lymphocytes, likely through virological synapses (VSs). These cell-cell junctions share some characteristics with immunological synapses, but cellular proteins required for their constitution remain poorly characterized. We have examined here the role of ZAP-70, a key kinase regulating T-cell activation and immunological synapse formation, in HIV replication.
View Article and Find Full Text PDFEngagement of the T-cell receptor (TCR) results in the activation of Lck/Fyn and ZAP-70/Syk tyrosine kinases. Lck-mediated tyrosine phosphorylation of signaling motifs (ITAMs) in the CD3-zeta subunits of the TCR is an initial step in the transduction of signaling cascades. However, zeta phosphorylation is also promoted by ZAP-70, as TCR-induced zeta phosphorylation is defective in ZAP-70-deficient T cells.
View Article and Find Full Text PDFLeukemic T cell lines have facilitated signal transduction studies but their physiological relevance is restricted. The use of primary T lymphocytes overcomes this limitation but it has long been speculated that methodological aspects of blood collection and the isolation procedure modify the phenotype of the cell. Here we demonstrate that several characteristics of human peripheral T cells are affected by the selection conditions.
View Article and Find Full Text PDFIL-22 is an IL-10 homologue that binds to and signals via the class II cytokine receptor (R) heterodimer IL-22RA1/CFR2-4 (IL-10R2), the latter chain being part of the IL-10R complex. Here, we report that, despite its structural similarity with IL-10, as well as its use of the common IL-10R2 chain, IL-22, in contrast to IL-10, is unable to induce Ig production by activated human B cells. Whereas culture of anti-CD40 mAb-stimulated splenic or tonsillar B cells in the presence of rIL-10 resulted in the production of IgG, IgG1, IgG3 and IgA, rIL-22, at concentrations ranging from 4 to 100 ng/ml, did not induce the production of any of these isotypes.
View Article and Find Full Text PDFMutations in the ZAP-70 protein tyrosine kinase gene result in a severe combined immunodeficiency (SCID) characterized by a selective inability to produce CD8(+) T cells and a signal transduction defect in peripheral CD4(+) cells. Transplantation of genetically modified hematopoietic progenitor cells that express the wild-type ZAP-70 gene may provide significant benefit to some of these infants. The feasibility of stem cell gene correction for human ZAP-70 deficiency was assessed using a ZAP-70 knock-out model.
View Article and Find Full Text PDFTransendothelial migration of activated lymphocytes from the blood into the tissues is an essential step for immune functions. The housekeeping chemokine CXCL12 (or stroma cell-derived factor-1alpha), a highly efficient chemoattractant for T lymphocytes, drives lymphocytes to sites where they are highly likely to encounter antigens. This suggests that cross-talk between the T-cell receptor (TCR) and CXCR4 (the CXCL12 receptor) might occur within these sites.
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