Abstract
The immunoglobulin G (IgG)-containing B lymphocyte antigen receptor (IgG-BCR) transmits a signal distinct from that of IgM-BCR or IgD-BCR, although all three use the same signal-transducing component, Igalpha/Igbeta. Here we demonstrate that the inhibitory coreceptor CD22 down-modulates signaling through IgM-BCR and IgD-BCR, but not that through IgG-BCR, because of the IgG cytoplasmic tail, which prevents CD22 phosphorylation. These results suggest that the cytoplasmic tail of IgG specifically enhances IgG-BCR signaling by preventing CD22-mediated signal inhibition. Enhanced signaling through IgG-BCR may be involved in efficient IgG production, which is crucial for immunity to pathogens.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD / metabolism
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Antigens, Differentiation, B-Lymphocyte / metabolism
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B-Lymphocytes / immunology
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B-Lymphocytes / metabolism
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Calcium / metabolism
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Calcium Signaling
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Cell Adhesion Molecules*
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Cells, Cultured
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Immunoglobulin D / immunology
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Immunoglobulin D / metabolism
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Immunoglobulin G / chemistry
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Immunoglobulin G / immunology
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Immunoglobulin G / metabolism*
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Intracellular Signaling Peptides and Proteins
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Lectins / metabolism
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Mice
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases / metabolism
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Phosphorylation
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases / metabolism
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Receptors, Antigen, B-Cell / chemistry
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Receptors, Antigen, B-Cell / immunology
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Receptors, Antigen, B-Cell / metabolism*
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Sialic Acid Binding Ig-like Lectin 2
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Signal Transduction*
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Transfection
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Tumor Cells, Cultured
Substances
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Antigens, CD
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Antigens, Differentiation, B-Lymphocyte
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CD72 protein, human
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Cd22 protein, mouse
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Cell Adhesion Molecules
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Immunoglobulin D
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Immunoglobulin G
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Intracellular Signaling Peptides and Proteins
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Lectins
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Receptors, Antigen, B-Cell
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Sialic Acid Binding Ig-like Lectin 2
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases
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PTPN6 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases
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Ptpn6 protein, mouse
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Calcium