Tyrosine phosphorylation of MB-1, B29, and HS1 proteins in human B cells following receptor crosslinking.
Recent studies of murine and human B lymphocytes have shown that crosslinking of surface IgM (sIgM) and sIgD stimulates tyrosine phosphorylation of a set of proteins involved in signal transduction. We investigated tyrosine phosphorylation of the sIg-associated proteins MB-1 and B29, and p75HS1 (HS1), and the association of HS1 with MB-1/B29 heterodimers in normal human B cells and a human B lymphoma cell line, B104. Using immunoprecipitation with anti-phosphotyrosine antibodies (Abs) followed by immunoblotting with anti-MB-1 Abs, anti-B29 Abs or anti-HS1 Abs, we demonstrated that MB-1, B29 and HS1 were tyrosine-phosphorylated after sIgM or sIgD crosslinking. Immunoprecipitation with anti-B29 Abs followed by anti-HS1 Abs immunoblotting revealed that HS1 was associated with MB-1/B29 heterodimers after sIgM or sIgD crosslinking. The results showed that HS1 may play an important role in signal transduction through sIgM and sIgD on human B cells.
Hata
D
D
Department of Pediatrics, Faculty of Medicine, Kyoto University, Japan.
Nakamura
T
T
Kawakami
T
T
Kawakami
Y
Y
Herren
B
B
Mayumi
M
M
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D001483:Base Sequence; D001798:Blood Proteins / Q000378:metabolism*; D051925:CD79 Antigens; D017931:DNA Primers; D006801:Humans; D007072:Immunoglobulin D / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D011961:Receptors, Fc / Q000276:immunology / Q000378:metabolism; D017452:Receptors, IgG / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D001798:Blood Proteins; D051925:CD79 Antigens; C497881:CD79A protein, human; C497883:CD79B protein, human; D017931:DNA Primers; C061909:HCLS1 protein, human; D007072:Immunoglobulin D; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D011947:Receptors, Antigen, B-Cell; D011961:Receptors, Fc; D017452:Receptors, IgG; C035311:immunoglobulin M receptor; D014443:Tyrosine