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Updated: Jul 14, 2026

Measuring G-protein-coupled Receptor Signaling via Radio-labeled GTP Binding
Published on: June 9, 2017
PU.1 and Spi-B are required for normal B cell receptor-mediated signal transduction
L A Garrett-Sinha1, G H Su, S Rao
1Howard Hughes Medical Institute, University of Chicago, Illinois 60637, USA.
Abstract:
PU.1 and Spi-B have previously been implicated in the regulation of genes encoding B cell receptor (BCR) signaling components. Spi-B-/- B lymphocytes respond poorly to BCR stimulation; PU.1-/- mice, however, lack B cells, precluding an analysis of BCR responses. We now show that PU.1+/- Spi-B-/- B cells exhibit more extensive defects than Spi-B-/- B cells, indicating that both PU.1 and Spi-B are required for normal BCR signaling. Strikingly, BCR cross-linking results in substantially reduced protein tyrosine phosphorylation in mutant B cells. Further analysis shows that Igalpha is phosphorylated and syk is recruited and becomes phosphorylated but that BLNK and PLCgamma phosphorylation are defective in mutant cells. Our data support the existence of a novel component coupling syk to downstream targets.
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