Regulation of B-lymphocyte activation by the PH domain adaptor protein Bam32/DAPP1

2007 ◽  
Vol 35 (2) ◽  
pp. 181-182 ◽  
Author(s):  
A.J. Marshall ◽  
T. Zhang ◽  
M. Al-Alwan
Keyword(s):  
B Cell ◽  
B Lymphocyte ◽  
Second Messengers ◽  
Lymphocyte Activation ◽  
Adaptor Protein ◽  
Cell Receptor ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
B Lymphocyte Activation ◽  
Signal Transduction Proteins

PI3Ks (phosphoinositide 3-kinases) play critical roles in BCR (B-cell receptor) signalling via the generation of 3-phosphoinositide second messengers. Recruitment of PH domain (pleckstrin homology domain)-containing signal transduction proteins to the plasma membrane through binding to 3-phosphoinositide second messengers represents a major effector mechanism for PI3Ks. Here, we review data on the PH domain-containing adaptor protein Bam32 (B-cell adaptor molecule of 32 kDa)/DAPP1 (dual adaptor for phosphotyrosine and 3-phosphoinositides 1), focusing on its functions in B-lymphocyte activation. Present results support the view that Bam32/DAPP1 mediates multiple PI3K-dependent responses in B-cells through membrane-proximal mechanisms involving Src kinases, Rac1, F-actin and mitogen-activated protein kinases, resulting in selective effects on BCR-mediated proliferation, antigen presentation and generation of antibody responses.

scholarly journals B-cell-stimulatory factor 1 reverses Fc receptor-mediated inhibition of B-lymphocyte activation.

1987 ◽  
Vol 84 (17) ◽  
pp. 6254-6258 ◽  
Author(s):  
A. O'Garra ◽  
K. P. Rigley ◽  
M. Holman ◽  
J. B. McLaughlin ◽  
G. G. Klaus
Keyword(s):  
B Cell ◽  
B Lymphocyte ◽  
Lymphocyte Activation ◽  
Fc Receptor ◽  
B Lymphocyte Activation ◽  
Stimulatory Factor

scholarly journals Syk-dependent Actin Dynamics Regulate Endocytic Trafficking and Processing of Antigens Internalized through the B-Cell Receptor

2007 ◽  
Vol 18 (9) ◽  
pp. 3451-3462 ◽  
Author(s):  
Delphine Le Roux ◽  
Danielle Lankar ◽  
Maria-Isabel Yuseff ◽  
Fulvia Vascotto ◽  
Takeaki Yokozeki ◽  
...  
Keyword(s):  
B Cell ◽  
Antigen Processing ◽  
B Lymphocyte ◽  
Lymphocyte Activation ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Actin Dynamics ◽  
Endocytic Trafficking ◽  
Mhc Ii ◽  
Antigen Processing And Presentation

Antigen binding to the B-cell receptor (BCR) induces multiple signaling cascades that ultimately lead to B lymphocyte activation. In addition, the BCR regulates the key trafficking events that allow the antigen to reach endocytic compartments devoted to antigen processing, i.e., that are enriched for major histocompatibility factor class II (MHC II) and accessory molecules such as H2-DM. Here, we analyze the role in antigen processing and presentation of the tyrosine kinase Syk, which is activated upon BCR engagement. We show that convergence of MHC II- and H2-DM–containing compartments with the vesicles that transport BCR-uptaken antigens is impaired in cells lacking Syk activity. This defect in endocytic trafficking compromises the ability of Syk-deficient cells to form MHC II-peptide complexes from BCR-internalized antigens. Altered endocytic trafficking is associated to a failure of Syk-deficient cells to properly reorganize their actin cytoskeleton in response to BCR engagement. We propose that, by modulating the actin dynamics induced upon BCR stimulation, Syk regulates the positioning and transport of the vesicles that carry the molecules required for antigen processing and presentation.

Regulation of B Lymphocyte Activation: The Roles of Receptor Cross-Linkage and B Cell Stimulatory Factor-1 (BSF-1)

1986 ◽  
pp. 336-347
Author(s):  
William E. Paul ◽  
Junichiro Mizuguchi ◽  
Peter Hornbeck ◽  
Wayne Tsang ◽  
Clifford Snapper ◽  
...  
Keyword(s):  
B Cell ◽  
B Lymphocyte ◽  
Lymphocyte Activation ◽  
B Lymphocyte Activation ◽  
Cross Linkage ◽  
Stimulatory Factor

scholarly journals Role of C'3 and Fc receptors in B-lymphocyte activation.

1975 ◽  
Vol 141 (3) ◽  
pp. 647-663 ◽  
Author(s):  
G Möller ◽  
A Coutinho
Keyword(s):  
B Cells ◽  
B Cell ◽  
Polyclonal Antibody ◽  
B Lymphocyte ◽  
Fc Receptors ◽  
Lymphocyte Activation ◽  
Antibody Synthesis ◽  
B Lymphocyte Activation ◽  
Cell Induction

Attempts were made to identify the non-Ig lymphocyte receptor responsible for B-cell induction by antigen and polyclonal B-cell activators (PBA). As a first step, the role of C'3 and Fc receptors was analyzed. It was shown that complement could be fixed onto B cells to such an extent that the lymphocytes could not bind complement-coated red cells, but this did not result in induction of polyclonal antibody synthesis, nor did it inhibit the lymphocytes response to PBA. However, the C'3 receptros possessed a passive focussing role in the induction of polyclonal antibody responses. Thus, PBA that had fixed complement activated polyclonal responses at lower concentrations than the same substances that had not fixed complement. Most likely the dual binding of PBA molecules to B cells by the PBA and the C'3 receptors caused more PBA molecules to be bound to each cell. However, the focussing function of the C'3 receptors was several orders of magnitude smaller than that of the Ig receptors. Analogous studies were carried out with Fc receptors. Binding of different types of antigen-antibody complexes did not cause activation of polyclonal or specific antibody synthesis, nor did it significantly interfere with induction of antibody synthesis by PBA substances.

scholarly journals Measles Virus Nucleocapsid Protein Binds to FcγRII and Inhibits Human B Cell Antibody Production

1997 ◽  
Vol 186 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Kissia Ravanel ◽  
Claire Castelle ◽  
Thierry Defrance ◽  
T. Fabian Wild ◽  
Dominique Charron ◽  
...  
Keyword(s):  
B Cell ◽  
B Lymphocytes ◽  
Mhc Class Ii ◽  
Antibody Production ◽  
Nucleocapsid Protein ◽  
Measles Virus ◽  
B Lymphocyte ◽  
Lymphocyte Activation ◽  
B Lymphocyte Activation

Despite the development of an efficient specific immune response during measles virus (MV) infection, an immunosuppression occurs contributing to secondary infections. To study the role of nucleocapsid protein (NP) in MV-induced immunosuppression, we produced recombinant MV NP. Purified recombinant NP exhibited biochemical, antigenic, and tridimensional structure similar to viral NP. By flow cytometry, we showed that viral or recombinant NP bound to human and murine B lymphocytes, but not to T lymphocytes. This binding was specific, independent of MHC class II expression, and dependent of the B lymphocyte activation state. The murine IIA1.6 B cell line, deficient in the Fc receptor for IgG (FcγRII) expression, did not bind NP efficiently. Transfected IIA1.6 cells expressing either murine FcγRIIb1 or b2, or human FcγRIIa, b1*, or b2 isoforms efficiently bound NP. Furthermore, this binding was inhibited up to 90% by monoclonal antibodies 2.4G2 or KB61 specific for murine and human FcγRII, respectively. Finally, the in vitro Ig synthesis of CD40- or Ig-activated human B lymphocytes in the presence of interleukin (IL)-2 and IL-10 was reduced by 50% in the presence of recombinant NP. These data demonstrate that MV NP binds to human and murine FcγRII and inhibits in vitro antibody production, and therefore suggests a role for NP in MV-induced immunosuppression.

Transmembrane Signals and Intracellular "Second Messengers" in the Regulation of Quiescent B-Lymphocyte Activation

1987 ◽  
Vol 95 (1) ◽  
pp. 37-57 ◽  
Author(s):  
JohnC. Cambier ◽  
LouisB. Justement ◽  
M. KarenNewell ◽  
ZhengZ. Chen ◽  
LesleyK. Harris ◽  
...  
Keyword(s):  
B Lymphocyte ◽  
Second Messengers ◽  
Lymphocyte Activation ◽  
B Lymphocyte Activation ◽  
Intracellular Second Messengers

Effects of Zidovudine on B Lymphocyte Activation

1994 ◽  
Vol 158 (1) ◽  
pp. 140-156 ◽  
Author(s):  
Daniel Widney ◽  
Sigal Yawetz ◽  
Meta van der Meyden ◽  
Steven A. Miles ◽  
Tadamitsu Kishimoto ◽  
...  
Keyword(s):  
B Lymphocyte ◽  
Lymphocyte Activation ◽  
B Lymphocyte Activation
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