生命科学
显示 73-96 个结果(共 4815 个结果)
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¥4949.10CD22, also known as Siglec-2 (sialic acid-binding immunoglobulin-like lectin-2) is a transmembrane glycoprotein binding alpha2,6-linked sialic acid-bearing ligands. Intracellular domain of CD22 recruits protein tyrosine phosphatase SHP-1 through the immunoreceptor tyrosine-based inhibitory motifs (ITIMs), thus setting a treshold for B cell receptor-mediated activation. CD22 also regulates B-cell response by involvement in controlling the CD19/CD21-Src-family protein tyrosine kinase amplification pathway and CD40 signaling. CD22 exhibits hallmarks of clathrin-mediated endocytic pathway.加入购物车
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¥4949.10CD3 complex is crucial in transducing antigen-recognition signals into the cytoplasm of T cells and in regulating the cell surface expression of the TCR complex. T cell activation through the antigen receptor (TCR) involves the cytoplasmic tails of the CD3 subunits CD3 gamma, CD3 delta, CD3 epsilon and CD3 zeta. These CD3 subunits are structurally related members of the immunoglobulins super family encoded by closely linked genes on human chromosome 11. The CD3 components have long cytoplasmic tails that associate with cytoplasmic signal transduction molecules. This association is mediated at least in part by a double tyrosine-based motif present in a single copy in the CD3 subunits. CD3 may play a role in TCR-induced growth arrest, cell survival and proliferation. The CD3 antigen is present on 68-82% of normal peripheral blood lymphocytes, 65-85% of thymocytes and Purkynje cells in the cerebellum. It is never expressed on B or NK cells. Decreased percentages of T lymphocytes may be observed in some autoimmune diseases.加入购物车
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¥4949.10CD45 (LCA, leukocyte common antigen) is a receptor-type protein tyrosine phosphatase ubiquitously expressed in all nucleated hematopoietic cells, comprising approximately 10% of all surface proteins in lymphocytes. CD45 glycoprotein is crucial in lymphocyte development and antigen signaling, serving as an important regulator of Src-family kinases. CD45 protein exists as multiple isoforms as a result of alternative splicing; these isoforms differ in their extracellular domains, whereas they share identical transmembrane and cytoplasmic domains. These isoforms differ in their ability to translocate into the glycosphingolipid-enriched membrane domains and their expression depends on cell type and physiological state of the cell. Besides the role in immunoreceptor signaling, CD45 is important in promoting cell survival by modulating integrin-mediated signal transduction pathway and is also involved in DNA fragmentation during apoptosis.加入购物车
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¥4949.10Immunoglobulin D (IgD) is expressed on the surface of naive mature B cells, thus later than IgM, and is coexpressed with it then. Triggered by antigen binding, it signals through the CD79 complex to activate the B cells. Expression of IgD is lost after the isotype switch. Soluble IgD is present in very small amounts in the serum. IgD can bind to basophils and mast cells to activate them in an IgE-independent way to participate in respiratory immune defense.加入购物车
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¥4949.10CD15 (Lewis x), also known as stage specific embryonic antigen-1 (SSEA-1) is a trisacharide determinant (3-fucosyl-N-acetyllactosamine) expressed on several glycolipids, glycoproteins and proteoglycans of various cell types, e.g. granulocytes, mast cells, monocytes, macrophages, cells of gastric mucosa, nervous system or various tumour cells. There are several variants of Lewis x, such as sialyl-Lewis x or sulphated Lewis x. Cells with high surface expression of Le(x) antigen exhibit strong self-aggregation, based on calcium-dependent Le(x)-Le(x) interaction. This process is involved for example in embryo compaction or in autoaggregation of teratocarcinoma cells. Sialyl-Le(x) and its isomer sialyl-Le(a) are ligands of selectins. CD15 expression has been extensively used to confirm diagnosis of Hodgkin´s disease.加入购物车
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¥3657.81CD152 / CTLA-4 is a homodimeric transmembrane protein similar to CD28 and binding the same ligands, i.e. CD80 (B7.1) and CD86 (B7.2), but with higher affinity. Unlike CD28 with important costimulating functions, CD152 acts as an important inhibitory receptor essential for modulation of the immune system. CD152 / CTLA-4 becomes transiently expressed on activated T cells and its malfunction can cause autoimmune diseases, such as insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, or thyroid-associated orbitopathy.加入购物车
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¥3657.81CD235a (Glycophorin A, GPA) is a transmembrane sialoglycoprotein expressed on erythrocytes and their precursors. Similarly to glycophorin B (GPB), these molecules provide the cells with a large mucin-like surface, which minimalizes aggregation between erythrocytes in the circulation. GPA is the carrier of blood group M and N specificities, while GPB accounts for S, s and U specificities. CD235a is a receptor of Hsa, an Streptococcus adhesin.加入购物车
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¥3657.81CD144 / VE-cadherin (cadherin 5) is the major cadherin that is present at endothelial junctions. It is also strictly endothelial specific. Under vascular permeability increasing conditions (and also in capillaries and veins) CD144 is being phosphorylated, which promotes its rapid and reversible internalization. On the contrary, binding of p120 catenin (delta1 catenin) maintains CD144 localization at the plasma membrane, which stabilizes the junction and reduces vascular permeability.加入购物车
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¥3657.81CD123 is the alpha chain of interleukin 3 receptor (IL-3R alpha). This subunit heterodimerizes with the interleukin 3 receptor beta chain (CD131), which is shared with other receptors. CD123 interacts with IL-3 specifically, but with low affinity, and association with the beta subunit confers high affinity binding to the receptor heterodimer. Both chains are required for signaling, but receptor activation and signal transduction depend on IL-3 binding to CD123 as the initial step.加入购物车
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¥3657.81CD5 antigen (T1; 67 kDa) is a human cell surface T-lymphocyte single-chain transmembrane glycoprotein. CD5 is expressed on all mature T-lymphocytes, most of thymocytes, subset of B-lymphocytes and on many T-cell leukemias and lymphomas. It is a type I membrane glycoprotein whose extracellular region contains three scavenger receptor cysteine-rich (SRCR) domains. The CD5 is a signal transducing molecule whose cytoplasmic tail is devoid of any intrinsic catalytic activity. CD5 modulates signaling through the antigen-specific receptor complex (TCR and BCR). CD5 crosslinking induces extracellular Ca++ mobilization, tyrosine phosphorylation of intracellular proteins and DAG production. Preliminary evidence shows protein associations with ZAP-70, p56lck, p59fyn, PC-PLC, etc. CD5 may serve as a dual receptor, giving either stimulatory or inhibitory signals depending both on the cell type and development stage. In thymocytes and B1a cells it seems to provide inhibitory signals, in peripheral mature T lymhocytes it acts as a costimulatory signal receptor. CD5 is the phenotypic marker of a B cell subpopulation involved in the production of autoreactive antibodies. Disease relevance: CD5 is a phenotypic marker for some B cell lymphoproliferative disorders (B-CLL, Hairy cell leukemia, etc.). The CD5+ popuation is expanded in some autoimmune disorders (rheumatoid arthritis, etc.). Herpes virus infections induce loss of CD5 expression in the expanded CD8+ human T cells.加入购物车
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¥3657.81HLA-DR, a member of MHC class II glycoproteins, that bind intracellularly processed peptides and present them to the Th cells, is composed of 36 kDa alpha chain and 27 kDa beta chain, both anchored in the plasma membrane. Together with other MHC II molecules HLA-DR plays a central role in the immune system.加入购物车
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¥3657.81CD83 is a 40-45 kDa heavily glycosylated type I cell surface glycoprotein of immunoglobulin family. It is expressed on the surface of mature dendritic cells, Langerhans cells in the skin, and interdigitating reticulum cells in the lymphoid tissues. Low expression of CD83 has been reported in activated T and B cells. Cytoplasmic expression of CD83 can be detected also in monocytes and macrophages. CD83 is involved in modulation of antigen presentation. Soluble CD83 has immunoregulatory functions, it is able to down-regulate dendritic cell maturation and stimulation of T cells. In the developing immune system, release of soluble CD83 from dendritic cells upon stimulation by gram-positive or gram-negative bacteria has anti-allergic effect. Herpes simplex virus, on the other hand, causes CD83 degradation in mature dendritic cells.加入购物车
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¥3657.81CD73 (ecto-5´-nucleotidase) is a 70 kDa glycoprotein anchored to the extracellular leaflet of the plasma membrane by GPI. This ecto-enzyme catalyzes dephosphorylation of AMP to adenosine. CD73 is expressed in various types of cells, such as epithelial, muscle, and endothelial cells, neutrophils, lymphocytes and fibroblasts. Inflammatory mediators support CD73 expression and its enzymatic activity, leading to the release of adenosine, which modulates inflammation through adenosine receptors. CD73 is expressed in a variety of lymphomas and leukemias, including ALL and CLL, whereas immunodeficient patients usually express low levels of this protein.加入购物车
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¥3657.81CD62P (P-selectin) is an adhesion glycoprotein that is expressed on platelets and endothelial cells upon their activation. Interaction between CD62P and its mucin-like ligand PSGL-1 (P-selectin glycoprotein ligand-1) expressed on the microvilli of most leukocytes supports leukocyte rolling along postkapillary venules at the earliest time of inflammation. Both CD62P and PSGL-1 are extended glycoproteins that form homodimers. CD62P dimerization is probably mediated through interactions of the transmembrane domains and stabilizes leukocyte tethering and rolling, probably by increasing rebinding within a bond cluster.加入购物车
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¥3657.81CD34 is a highly glycosylated monomeric 111-115 kDa surface protein, which is present on many stem cell populations. It is a well established stem cell marker, though its expression on human hematopoietic stem cells is reversible. CD34 probably serves as a surface receptor that undergoes receptor-mediated endocytosis and regulates adhesion, differentiation and proliferation of hematopoietic stem cells and other progenitors. CD34 expression is likely to represent a specific state of hematopoietic development that may have altered adhering properties with expanding and differentiating capabilities in both in vitro and in vivo conditions.加入购物车
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¥3657.81CD19 is a transmembrane glycoprotein of Ig superfamily expressed by B cells from the time of heavy chain rearrangement until plasma cell differentiation. It forms a tetrameric complex with CD21 (complement receptor type 2), CD81 (TAPA-1) and Leu13. Together with BCR (B cell antigen receptor), this complex signals to decrease B cell treshold for activation by the antigen. Besides being signal-amplifying coreceptor for BCR, CD19 can also signal independently of BCR coligation and it turns out to be a central regulatory component upon which multiple signaling pathways converge. Mutation of the CD19 gene results in hypogammaglobulinemia, whereas CD19 overexpression causes B cell hyperactivity.加入购物车
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¥3657.81CD33 is a transmembrane protein of the sialic acid-binding immunoglobulin-like lectin (Siglec) family. It belongs to the immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing molecules able of recruiting protein tyrosine phosphatases SHP-1 and SHP-2 to signal assemblies; these ITIMs are also used for ubiquitin-mediated removal of the receptor from the cell surface. CD33 is expressed on cells of myelomonocytic lineage, binds sialic acid residues in N- and O-glycans on cell surfaces, and is a therapeutic target for acute myeloid leukemia.加入购物车
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¥3657.81CD90 (Thy-1) is an 18-35 kDa GPI-anchored plasma membrane glycoprotein expressed in many cell types, such as in hematopoietic cells and neurons, connective tissues, various fibroblast and stromal cell lines, tumor endothelial cell lines and other. It is involved in T cell activation, cellular adhesion, proliferation and migration, neurite outgrowth, wound healing, apoptosis, and fibrosis. CD90 participates in multiple signaling cascades and its effects are tissue- and cell type-specific. It often functions as an important regulator of cell-cell and cell-matrix interactions.加入购物车
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¥3657.81CD16 (FcgammaRIII) is a 50-65 kDa glycoprotein serving as a low affinity IgG receptor. Human FcgammaRIII is expressed in two forms – FcgammaRIII-A and -B. FcgammaRIII-A is a transmembrane protein of monocytes, macrophages, NK cells and a subset of T cells. It is associated with FcepsilonRI-gamma subunit and is responsible for antibody-dependent NK cell cytotoxicity. Mast cell FcgammaRIII-A is associated, moreover, with FcepsilonRI-beta subunit. Besides IgG, FcgammaRIII-A can be triggered also by oligomeric IgE. FcgammaRIII-B is a GPI-linked monomeric receptor expressed on neutrophils and is involved in their activation and induction of a proadhesive phenotype.加入购物车
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¥3657.81CD64 (FcgammaRI) is a cell surface receptor for Fc region of IgG. It is composed of specific ligand binding alpha subunit and promiscuous gamma subunit, which is indispensable for tyrosine-based signaling. However, even the alpha subunit can transduce signals leading to cellular effector functions. The isoform FcgammaRIa1 binds human IgG with high affinity, has limited myeloid cell distribution, and a relatively large intracellular domain. Products of related genes include FcgammaRIb and FcgammaRIc isoforms, but these specify low affinity IgG receptors if functionally expressed at all. Besides a role in antigen clearance, FcgammaRI (a1) can potently enhance MHC class I and II antigen presentation in vitro and in vivo.加入购物车
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¥3657.81CD20 is a cell surface 33-37 (depending on the degree of phosphorylation) kDa non-glycosylated surface phosphoprotein expressed on mature and most malignant B cells, but not stem cells or plasma cells (low number of the CD20 has been also detected on a subpopulation of T lymphocytes and it can be expressed on follicular dendritic cells). Its expression on B cells is synchronous with the expression of surface IgM. CD20 regulates transmembrane calcium conductance (probably functioning as a component of store-operated calcium channel), cell cycle progression and B-cell proliferation. It is associated with lipid rafts, but the intensity of this association depends on extracellular triggering, employing CD20 conformational change and/or BCR (B cell antigen receptor) aggregation. After the receptor ligation, BCR and CD20 colocalize and then rapidly dissociate before BCR endocytosis, whereas CD20 remains at the cell surface. CD20 serves as a useful target for antibody-mediated therapeutic depletion of B cells, as it is expressed at high levels on most B-cell malignancies, but does not become internalized or shed from the plasma membrane following mAb treatment.加入购物车
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¥3657.81CD158d / KIR2DL4 is a KIR family member that shares structural features with both activating and inhibitory receptors and may mediate different functions under different circumstances. It contains cytoplasmic ITIM, suggesting inhibitory function, but also transmembrane domain similar to those of activating KIRs. It has been reported that CD158d serves as an inhibitory receptor for peripheral and uterine NK cells, but its ligation with soluble mAbs (unlike immobilized mAbs) results in activation of IFN-γ secretion. CD158d also binds both membrane form and soluble form of its ligand HLA-G.加入购物车