Background

Antibodies to Proteins involved in the B-Cell Activation

• BANK1, B-cell scaffold protein with ankyrin repeats
  nvolved in B-cell receptor (BCR)-induced Ca2+ mobilization from intracellular stores. Promotes Lyn-mediated phosphorylation of IP3 receptors 1 and 2. Expressed in B-cell but not T-cell or myeloid cell lines. Highest expression in CD19+ B-cells, with very low expression in other cell populations.
• BLNK, B-cell linker protein (B-cell adapter containing a SH2 domain protein) (B-cell adapter containing a Src homology 2 domain protein) (Cytoplasmic adapter protein) (Src homology 2 domain-containing leukocyte protein of 65 kDa) (SLP-65)
  Functions as a central linker protein that bridges kinases associated with the B-cell receptor (BCR) with a multitude of signaling pathways, regulating biological outcomes of B-cell function and development. Plays a role in the activation of ERK/EPHB2, MAP kinase p38 and JNK. Modulates AP1 activation. Important for the activation of NF-kappa-B and NFAT. Plays an important role in BCR-mediated PLCG1 and PLCG2 activation and Ca2+ mobilization and is required for trafficking of the BCR to late endosomes. However, does not seem to be required for pre-BCR-mediated activation of MAP kinase and phosphatidyl-inositol 3 (PI3) kinase signaling. May be required for the RAC1-JNK pathway. Plays a critical role in orchestrating the pro-B cell to pre-B cell transition. Plays an important role in BCR-induced B-cell apoptosis. Expressed in B-cell lineage and fibroblast cell lines (at protein level). Highest levels of expression in the spleen, with lower levels in the liver, kidney, pancreas, small intestines and colon.
• BST2, Bone marrow stromal antigen 2 (BST-2) (HM1.24 antigen) (Tetherin) (CD antigen CD317)
  May be involved in the sorting of secreted proteins. May be involved in pre-B-cell growth. Antiretroviral defense protein, that blocks release of enveloped virus from the cell surface. Active against at least four virus families: retroviruses, filoviruses, arenaviruses, and herpesviruses. Depleted unpon HIV-1 infection by viral VPU protein through 20S proteasome degradation. Depleted upon infection by human Kaposis sarcoma-associated herpesvirus (KSHV) through ubiquitination and subsequent degradation. May play a role in B-cell activation in rheumatoid arthritis. Predominantly expressed in liver, lung, heart and placenta. Lower levels in pancreas, kidney, skeletal muscle and brain. Overexpressed in multiple myeloma cells. Highly expressed during B-cell development, from pro-B precursors to plasma cells. Highly expressed on T-cells, monocytes, NK cells and dendritic cells (at protein level).
• CXCR5, C-X-C chemokine receptor type 5 (CXC-R5) (CXCR-5) (Burkitt lymphoma receptor 1) (Monocyte-derived receptor 15) (MDR-15) (CD antigen CD185)
  Cytokine receptor that binds to B-lymphocyte chemoattractant (BLC). Involved in B-cell migration into B-cell follicles of spleen and Peyer patches but not into those of mesenteric or peripheral lymph nodes. May have a regulatory function in Burkitt lymphoma (BL) lymphomagenesis and/or B-cell differentiation. Expression in mature B-cells and Burkitt lymphoma cells.
• ICOSLG, ICOS ligand (B7 homolog 2) (B7-H2) (B7-like protein Gl50) (B7-related protein 1) (B7RP-1) (CD antigen CD275)
  Ligand for the T-cell-specific cell surface receptor ICOS. Acts as a costimulatory signal for T-cell proliferation and cytokine secretion; induces also B-cell proliferation and differentiation into plasma cells. Could play an important role in mediating local tissue responses to inflammatory conditions, as well as in modulating the secondary immune response by co-stimulating memory T-cell function. Isoform 1 is widely expressed, while isoform 2 is detected only in lymph nodes, leukocytes and spleen. Expressed on activated monocytes and dendritic cells
• IGBP1, Immunoglobulin-binding protein 1 (B-cell signal transduction molecule alpha 4) (Protein alpha-4) (CD79a-binding protein 1) (Renal carcinoma antigen NY-REN-16)
  Associated to surface IgM-receptor; may be involved in signal transduction. May be involved in regulation of the catalytic activity of type 2A-related serine/threonine phosphatases.
• IKZF3, Zinc finger protein Aiolos (Ikaros family zinc finger protein 3)
  Transcription factor that plays an important role in the regulation of lymphocyte differentiation. Plays an essential role in regulation of B-cell differentiation, proliferation and maturation to an effector state. Involved in regulating BCL2 expression and controlling apoptosis in T-cells in an IL2-dependent manner. Expressed most strongly in peripheral blood leukocytes, the spleen, and the thymus.
• IL4, Interleukin-4 (IL-4) (B-cell stimulatory factor 1) (BSF-1) (Binetrakin) (Lymphocyte stimulatory factor 1) (Pitrakinra)
  Participates in at least several B-cell activation processes as well as of other cell types. It is a costimulator of DNA-synthesis. It induces the expression of class II MHC molecules on resting B-cells. It enhances both secretion and cell surface expression of IgE and IgG1. It also regulates the expression of the low affinity Fc receptor for IgE (CD23) on both lymphocytes and monocytes.
• MS4A1, B-lymphocyte antigen CD20 (B-lymphocyte surface antigen B1) (Bp35) (Leukocyte surface antigen Leu-16) (Membrane-spanning 4-domains subfamily A member 1) (CD antigen CD20)
  This protein may be involved in the regulation of B-cell activation and proliferation. Expressed on B-cells.
• SKAP2, Src kinase-associated phosphoprotein 2 (Pyk2/RAFTK-associated protein) (Retinoic acid-induced protein 70) (SKAP55 homolog) (SKAP-55HOM) (SKAP-HOM) (Src family-associated phosphoprotein 2) (Src kinase-associated phosphoprotein 55-related protein) (Src-associated adapter protein with PH and SH3 domains)
  May be involved in B-cell and macrophage adhesion processes. In B-cells, may act by coupling the B-cell receptor (BCR) to integrin activation. May play a role in src signaling pathway.

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