Identification of two distinct phosphoproteins as components of the human B cell antigen receptor complex

• Published in: European journal of immunology Vol. 20; no. 12; p. 2789
• Main Authors: Van Noesel, C J, Borst, J, De Vries, E F, Van Lier, R A
• Format: Journal Article
• Language: English
• Published: Germany 01.12.1990
• Subjects: B-Lymphocytes - physiology; Chromatography, High Pressure Liquid; Disulfides; Glycoproteins - physiology; Humans; Immunoglobulin M - physiology; Macromolecular Substances; Molecular Weight; Peptide Mapping; Phosphoproteins - chemistry; Phosphoproteins - physiology; Phosphoserine - metabolism; Receptors, Antigen, B-Cell - chemistry; Receptors, Antigen, B-Cell - physiology
• DOI: 10.1002/eji.1830201238
• ISSN: 0014-2980

In human B cells, the molecules that, upon receptor occupancy, couple membrane immunoglobulin to intracellular signal transduction pathways have never been identified. We here describe two phosphoproteins as integral parts of the B cell antigen receptor complex. Membrane IgM is non-covalently associated with a disulfide-linked heterodimer of glycoproteins. These molecules can be demonstrated on B cell lines and freshly isolated polyclonal B cell populations and are subject to phosphorylation at serine residues. Identification of these constituents of the B cell receptor complex opens up the opportunity to study coupling of the B cell antigen receptor to the intracellular signal transduction machinery at the molecular level.