Signaling-defective mutants of the B lymphocyte antigen receptor fail to associate with Ig-alpha and Ig-beta/gamma.
The B cell receptor for antigen, the membrane immunoglobulin (mIg) molecule, is normally expressed in association with at least two other proteins, mb-1 (Ig-alpha) and B29 (Ig-beta/gamma). We have previously described a set of murine B cell clones transfected with wild-type and mutated forms of membrane-bound IgM (mIgM) that vary in their ability to transduce signals to the cell interior. Analysis of the B cell receptor complex in signaling and nonsignaling mutants of mIgM reveals complete concordance between intact signaling ability and ability of the mIgM to associate with Ig-alpha and Ig-beta/gamma. These results point to the importance of the mIgM transmembrane region in mediating binding to accessory molecules, and provide support for a role of Ig-alpha and Ig-beta/gamma that extends beyond surface expression to signal transduction in B lymphocytes.
Grupp
S A
SA
Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115.
Campbell
K
K
Mitchell
R N
RN
Cambier
J C
JC
Abbas
A K
AK
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology*; D015153:Blotting, Western; D051925:CD79 Antigens; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D007075:Immunoglobulin M / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D016393:Lymphoma, B-Cell; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D051925:CD79 Antigens; C497881:CD79A protein, human; C497883:CD79B protein, human; C497882:Cd79a protein, mouse; C497884:Cd79b protein, mouse; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D011947:Receptors, Antigen, B-Cell; D011494:Protein Kinases; D002118:Calcium