title: Clustering of the B cell receptor is not required for the apoptotic response.
abstract: We examined the role of BCR cell membrane redistribution in anti-IgM-induced apoptosis in three human B cell lines, RA#1, 2G6, and MC116, that differ in their relative levels of sIgM expression. The apoptotic response was found to be dependent on the nature of the anti-IgM and the cell line. In the cell lines, RA#1 and MC116, sIgM aggregated into patches that were insensitive to the disruption of cholesterol-rich membrane microdomains by nystatin or beta-MCD. The B cell line 2G6 was able to reorganize sIgM into a tight coalescent cap upon anti-IgM treatment. However, in this case, the lipid raft inhibitors nystatin and beta-MCD disrupted the patching. In 2G6 cells, BCR-mediated apoptosis was not affected by nystatin treatment, whereas it increased in beta-MCD pretreated cells. Thus, no evident correlation was found between apoptosis and BCR cell membrane redistribution or lipid raft formation in either of the three cell lines. The data indicate that the apoptotic signal transduction pathway is independent of BCR translocation into lipid rafts and/or aggregation.
authors.affiliation: Department of Medicine, Division of Endocrinology, Mayo Clinic/Mayo Foundation, Rochester, Minnesota 55905, USA.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Trujillo
authors.forename: Shi-Wen
authors.initials: SW
authors.lastname: Jiang
authors.forename: James E
authors.initials: JE
authors.lastname: Tarara
authors.forename: Norman L
authors.initials: NL
authors.lastname: Eberhardt
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D017209:Apoptosis; D002462:Cell Membrane / Q000276:immunology; D006801:Humans; D007075:Immunoglobulin M / Q000187:drug effects; D007152:Immunologic Capping; D018613:Microscopy, Confocal; D009761:Nystatin / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell; C044203:anti-IgM; D009761:Nystatin