TCR-induced transmembrane signaling by peptide/MHC class II via associated Ig-alpha/beta dimers.
Previous findings suggest that during cognate T cell-B cell interactions, major histocompatability complex (MHC) class II molecules transduce signals, leading to Src-family kinase activation, Ca2+ mobilization, and proliferation. Here, we show that antigen stimulation of resting B cells induces MHC class II molecules to associate with Immunoglobulin (Ig)-alpha/Ig-beta (CD79a/CD79b) heterodimers, which function as signal transducers upon MHC class II aggregation by the T cell receptor (TCR). The B cell receptor (BCR) and MHC class II/Ig-alpha/Ig-beta are distinct complexes, yet class II-associated Ig-alpha/beta appears to be derived from BCR. Hence, Ig-alpha/beta are used in a sequential fashion for transduction of antigen and cognate T cell help signals.
Integrated Department of Immunology, University of Colorado Health Sciences Center, and National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA.
P
P
Lang
J C
JC
Stolpa
B A
BA
Freiberg
F
F
Crawford
J
J
Kappler
A
A
Kupfer
J C
JC
Cambier
D000818:Animals; D000941:Antigens / Q000276:immunology; D015703:Antigens, CD / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D051925:CD79 Antigens; D002478:Cells, Cultured; D019281:Dimerization; D004789:Enzyme Activation; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism*; D015151:Immunoblotting; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000276:immunology / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014158:Transcription, Genetic
D000941:Antigens; D015703:Antigens, CD; D051925:CD79 Antigens; C497882:Cd79a protein, mouse; C497884:Cd79b protein, mouse; D000949:Histocompatibility Antigens Class II; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases