TY - JOUR
T1 - Bap-135, a target for Bruton's tyrosine kinase in response to B cell receptor engagement
AU - Yang, Weiyi
AU - Desiderio, Stephen
PY - 1997/1/21
Y1 - 1997/1/21
N2 - Bruton's tyrosine kinase (Btk) is essential for B cell activation, but downstream targets of Btk have not been defined. We now describe a protein, BAP-135, that is associated with Btk in B cells and is a substrate for phosphorylation by Btk. BAP-135, which exhibits no detectable homology to known proteins, contains six occurrences of a hitherto undescribed amino acid repeat and two motifs, similar to the Src autophosphorylation site, that represent potential targets for tyrosine phosphorylation. The pleckstrin homology domain of Btk comprises the principal site of BAP-135 binding. Btk- dependent phosphorylation of BAP-135 is abolished by mutations that impair activation of Btk by Src-related kinases. Btk and BAP-135 exist in a complex before B cell antigen receptor (BCR) engagement; in response to BCR crosslinking, BAP-135 is transiently phosphorylated on tyrosine. Taken together, these observations suggest that BAP-135 may reside downstream of Btk in a signaling pathway originating at the BCR.
AB - Bruton's tyrosine kinase (Btk) is essential for B cell activation, but downstream targets of Btk have not been defined. We now describe a protein, BAP-135, that is associated with Btk in B cells and is a substrate for phosphorylation by Btk. BAP-135, which exhibits no detectable homology to known proteins, contains six occurrences of a hitherto undescribed amino acid repeat and two motifs, similar to the Src autophosphorylation site, that represent potential targets for tyrosine phosphorylation. The pleckstrin homology domain of Btk comprises the principal site of BAP-135 binding. Btk- dependent phosphorylation of BAP-135 is abolished by mutations that impair activation of Btk by Src-related kinases. Btk and BAP-135 exist in a complex before B cell antigen receptor (BCR) engagement; in response to BCR crosslinking, BAP-135 is transiently phosphorylated on tyrosine. Taken together, these observations suggest that BAP-135 may reside downstream of Btk in a signaling pathway originating at the BCR.
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U2 - 10.1073/pnas.94.2.604
DO - 10.1073/pnas.94.2.604
M3 - Article
C2 - 9012831
AN - SCOPUS:0031038046
SN - 0027-8424
VL - 94
SP - 604
EP - 609
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 2
ER -