Search results for "Cell surface receptor"

2021

Both plants and animals are endowed with sophisticated innate immune systems to combat microbial attack. In these multicellular eukaryotes, innate immunity implies the presence of cell surface receptors and intracellular receptors able to detect danger signal referred as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Membrane-associated pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), C-type lectin receptors (CLRs), receptor-like kinases (RLKs), and receptor-like proteins (RLPs) are employed by these organisms for sensing different invasion patterns before triggering antimicrobial defenses that can be associated with…

Comparison of binding properties and early biological effects of elicitins in tobacco cells

1998

Abstract Elicitins are a family of small proteins secreted by Phytophthora species that have a high degree of homology and elicit defense reactions in tobacco (Nicotiana tabacum). They display acidic or basic characteristics, the acidic elicitins being less efficient in inducing plant necrosis. In this study we compared the binding properties of four elicitins (two basic and two acidic) and early-induced signal transduction events (Ca2+ influx, extracellular medium alkalinization, and active oxygen species production). The affinity for tobacco plasma membrane-binding sites and the number of binding sites were similar for all four elicitins. Furthermore, elicitins compete with one another fo…

The Stalk Domain of NKp30 Contributes to Ligand Binding and Signaling of a Preassembled NKp30-CD3ζ Complex

2016

The natural cytotoxicity receptor (NCR) NKp30 (CD337) is a key player for NK cell immunosurveillance of infections and cancer. The molecular details of ligand recognition and its connection to CD3ζ signaling remain unsolved. Here, we show that the stalk domain (129KEHPQLGAGTVLLLR143) of NKp30 is very sensitive to sequence alterations, as mutations lead to impaired ligand binding and/or signaling capacity. Surprisingly, the stalk domains of NKp30 and NKp46, another NCR employing CD3ζ for signaling, were not exchangeable without drastic deficiencies in folding, plasma membrane targeting, and/or ligand-induced receptor signaling. Further mutational studies, N-glycosylation mapping, and plasma …

CNS Macrophages Control Neurovascular Development via CD95L.

2017

The development of neurons and vessels shares striking anatomical and molecular features, and it is presumably orchestrated by an overlapping repertoire of extracellular signals. CNS macrophages have been implicated in various developmental functions, including the morphogenesis of neurons and vessels. However, whether CNS macrophages can coordinately influence neurovascular development and the identity of the signals involved therein is unclear. Here, we demonstrate that activity of the cell surface receptor CD95 regulates neuronal and vascular morphogenesis in the post-natal brain and retina. Furthermore, we identify CNS macrophages as the main source of CD95L, and macrophage-specific del…

Reorganization of platelet membrane sphingomyelins by adenosine diphosphate and ticagrelor

2018

IF 2.766 (2017); International audience; Platelets are major targets for the treatment of thrombo-embolic disorders. Their plasma membrane contains specialized microdomains enriched in sphingomyelins and free cholesterol including membrane receptors. P2Y12 receptors need to be situated in these domains to be able to conduct activation signaling by adenosine diphosphate (ADP). We studied the impact of ticagrelor, a P2Y12 antagonist, and ADP on the composition and distribution of sphingomyelins in detergent-resistant membrane (DRM) of platelet membranes. Platelets were obtained from healthy donors. DRMs of platelet membranes were isolated in 4 experimental groups: control; ADP, with platelets…

Proangiogenic TF-FVIIa-PAR2 Signaling Requires Matriptase-Independent Integrin Interaction

2016

Abstract The close link between coagulation activation and cancer progression is supported by clinical and experimental studies. A central molecular pathways by which tumor cells interact with the hemostatic system is through the expression of the cell surface receptor tissue factor (TF) that in complex with coagulation factor VIIa (FVIIa) triggers the extrinsic pathway of blood coagulation, contributes to cancer associated thrombosis, and promotes direct tumor cell signaling through protease-activated receptors (PARs). Genetic and pharmacological evidence shows that epithelial and tumor cell TF-FVIIa signaling induces a diverse set of proangiogenic and immune modulatory cytokines, chemokin…

Melatonin reduces inflammatory response in human intestinal epithelial cells stimulated by interleukin‐1β

2019

Melatonin is the main secretory product of the pineal gland, and it is involved in the regulation of periodic events. A melatonin production independent of the photoperiod is typical of the gut. However, the local physiological role of melatonin at the intestinal tract is poorly characterized. In this study, we evaluated the anti-inflammatory activities of melatonin in an in vitro model of inflamed intestinal epithelium. To this purpose, we assessed different parameters usually associated with intestinal inflammation using IL-1 beta-stimulated Caco-2 cells. Differentiated monolayers of Caco-2 cells were preincubated with melatonin (1 nmol/L-50 mu mol/L) and then exposed to IL-1 beta. After …

Induction of the cytokine TWEAK and its receptor Fn14 in ischemic stroke.

2008

Stroke outcome is determined by delayed neuronal cell death and edema formation. TWEAK, a cytokine of the TNF superfamily, and its membrane receptor Fn14 promote ischemia-induced neuronal apoptosis and leakage of the blood-brain barrier. Both TWEAK and Fn14 are upregulated in experimental stroke models. In this study, we investigated whether TWEAK and Fn14 are upregulated in stroke patients. We measured serum concentrations of TWEAK in stroke patients and matched control subjects by ELISA. Expression of Fn14 in the brain was evaluated by real-time RT-PCR and immunohistochemistry. TWEAK serum concentrations were elevated in stroke patients. In autopsy samples, we found elevated mRNA levels o…

Alternative pathway activation of T cells by binding of CD2 to its cell-surface ligand.

1987

Activation of resting T lymphocytes is initiated by the interaction of cell-surface receptors with their corresponding ligands. In addition to activation through the CD3 (T3)-Ti antigen-receptor complex1, recent experiments have demonstrated induction of T-cell proliferation through the CD2 (T11) molecule2–4, traditionally known as the erythrocyte(E)-receptor, through which T cells can bind red blood cells (RBC)5–7. This 'alternative pathway' of T-cell activation2 was observed in vitro in response to combinations of anti-CD2 monoclonal antibodies (mAbs) that bind to distinct epitopes of CD2, such as mAbs against T112 plus T113 (ref. 2). The physiological importance of this activation pathwa…

Functional Role of Lipoprotein Receptors in Alzheimers Disease

2008

The LDL receptor gene family constitutes a class of structurally closely related cell surface receptors fulfilling diverse functions in different organs, tissues, and cell types. The LDL receptor is the prototype of this family, which also includes the VLDLR, ApoER2/LRP8, LRP1 and LRP1B, as well as Megalin/GP330, SorLA/LR11, LRP5, LRP6 and MEGF7. Recently several lines of evidence have positioned the LDL receptor gene family as one of the key players in Alzheimer's disease (AD) research. Initially this receptor family was of high interest due to its key function in cholesterol/apolipoprotein E (ApoE) uptake, with the epsilon4 allele of ApoE as the strongest genetic risk factor for late-onse…