A distinct signaling pathway used by the IgG-containing B cell antigen receptor.
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.
Wakabayashi
Chisato
C
Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, 113-8510 Tokyo, Japan.
Adachi
Takahiro
T
Wienands
Jurgen
J
Tsubata
Takeshi
T
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D007072:Immunoglobulin D / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051918:Sialic Acid Binding Ig-like Lectin 2; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C064228:CD72 protein, human; C497868:Cd22 protein, mouse; D015815:Cell Adhesion Molecules; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins; D011947:Receptors, Antigen, B-Cell; D051918:Sialic Acid Binding Ig-like Lectin 2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509248:Ptpn6 protein, mouse; D002118:Calcium