The complexity of signaling pathways activated by the BCR.
Cross-linking of the B cell antigen receptor (BCR) leads to the activation of three types of intracellular protein tyrosine kinases. These tyrosine kinases then phosphorylate signaling components to activate a variety of signaling reactions, including phosphatidylinositol 4,5-bisphosphate hydrolysis, Ras activation, and phosphatidylinositol 3-kinase activation. Each of these signaling reactions, and also the signaling molecules Vav and HS1, appears to be important for at least some of the many types of B cell responses to antigen. The complexity of BCR signaling reactions may be required to allow the B cell to respond in a number of distinct ways to antigen (proliferation, survival, apoptosis, maturational arrest, etc.) depending on the maturation state of the B cell, the location in the body, the physical nature of the antigen, and the possible presence of the antigen in complex with antibody or complement components.
DeFranco
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George Williams Hooper Foundation, Department of Microbiology, University of California, San Francisco, CA 94143-0552, USA. defranco@socrates.ucsf.edu
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation / Q000502:physiology*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D015398:Signal Transduction / Q000276:immunology*
D011947:Receptors, Antigen, B-Cell