D. Hata et al., TYROSINE PHOSPHORYLATION OF MB-1, B29, AND HS1 PROTEINS IN HUMAN B-CELLS FOLLOWING RECEPTOR CROSS-LINKING, Immunology letters, 40(1), 1994, pp. 65-71
Recent studies of murine and human B lymphocytes have shown that cross
linking of surface IgM (sIgM) and sIgD stimulates tyrosine phosphoryla
tion of a set of proteins involved in signal transduction. We investig
ated tyrosine phosphorylation of the sig-associated proteins MB-1 and
B29, and p75(HS1) (HS1), and the association of HS1 with MB-1/B29 hete
rodimers in normal human B cells and a human B lymphoma cell line, B10
4. 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-phosphor
ylated 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 tran
sduction through sIgM and sIgD on human B cells.