Structure and signalling functions of C3 receptors on human B cells.
CR1 (C3b receptor) and CR2 (C3d/EBV receptor) are two C3 receptors expressed on B lymphocytes. CR1 and CR2 have structural similarities and their cross-linking at the B cell surface by antibodies or specific ligands in multimeric forms induce B cell activation. However, activation of human B cells through cell surface interactions or by intracellular protein kinase C activators leads to phosphorylation of CR2 but not CR1. CR2 is phosphorylated on serine and tyrosine residues. Analysis of post-membrane events associated with CR2 revealed intracellular interactions of CR2 with p53, a plasma membrane anti-oncogene-encoded phosphoprotein, and with p120, a nuclear phosphoribonucleoprotein. These intracellular interactions probably represent important steps in the signalling functions of CR2.
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Immunochimie des Antigènes de Membrane et des Interactions Cellularies, INSERM U.23, Hôpital Saint-Antoine, Paris, France.
D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology; D001402:B-Lymphocytes / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation; D011951:Receptors, Complement / Q000502:physiology*; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d; D015398:Signal Transduction / Q000276:immunology*
D000944:Antigens, Differentiation, B-Lymphocyte; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d