title: The IgG1 B-cell receptor provides survival and proliferative signals analogue to the Igα but not the Igβ co-receptor.
abstract: The function of the IgM B-cell receptor (BCR) is dependent on intact signaling of the co-receptors Igα and Igβ, both of which contain a cytoplasmic tail bearing an immunoreceptor tyrosine-based activation motif. We have previously demonstrated that the cytoplasmic tail of the IgG1 BCR can partially compensate for the loss of the signaling moiety of Igα. Here, we show that unlike Igα, Igβ signaling is indispensable for the development and function of IgG1-expressing B cells. Deletion of the cytoplasmic signaling tail of Igβ compromised the survival and proliferation not only of IgM(+) B cells but also of IgG1-expressing B cells. In the absence of the signaling tail of Igβ, the transcription levels of the antiapoptotic gene bcl-xl and the cell-cycle gene ccnd2 were reduced, consistent with the observed defects in survival and proliferation. These results demonstrate functional differences between Igα and Igβ in the transduction of IgG1 BCR signal.
authors.affiliation: Institute for Molecular Medicine, University of Medical Centre of the Johannes, Gutenberg University of Mainz, Mainz, Germany.|Institute of Physiological Chemistry and Pathobiochemistry, University of Muenster, Muenster, Germany.
authors.forename: Jian
authors.initials: J
authors.lastname: Song
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Uyttersprot
authors.affiliation: Institute for Genetics, University of Cologne, Cologne, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Classen
authors.affiliation: Institute for Molecular Medicine, University of Medical Centre of the Johannes, Gutenberg University of Mainz, Mainz, Germany.
authors.forename: Ari
authors.initials: A
authors.lastname: Waisman
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D051925:CD79 Antigens / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation; D056742:Cyclin D2 / Q000378:metabolism; D005434:Flow Cytometry; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D051379:Mice; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism*; D015398:Signal Transduction; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: C494812:Bcl2l1 protein, mouse; D051925:CD79 Antigens; C486196:Ccnd2 protein, mouse; D056742:Cyclin D2; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; D051020:bcl-X Protein
keywords: B-cell development; BCR, Cytoplasmic tail deletion; IgG1; Igα/β