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Updated: Aug 8, 2026

A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
Published on: March 22, 2012
SLP-65: a new signaling component in B lymphocytes which requires expression of the antigen receptor for
J Wienands1, J Schweikert, B Wollscheid
1Department for Molecular Immunology, Biology III, University of Freiburg, 79104 Freiburg, Germany. wienanands@immunbio.mpg.de
Abstract:
The B cell antigen receptor (BCR) consists of the membrane-bound immunoglobulin (Ig) molecule as antigen-binding subunit and the Ig-alpha/Ig-beta heterodimer as signaling subunit. BCR signal transduction involves activation of protein tyrosine kinases (PTKs) and phosphorylation of several proteins, only some of which have been identified. The phosphorylation of these proteins can be induced by exposure of B cells either to antigen or to the tyrosine phosphatase inhibitor pervanadate/H2O2. One of the earliest substrates in B cells is a 65-kD protein, which we identify here as a B cell adaptor protein. This protein, named SLP-65, is part of a signaling complex involving Grb-2 and Vav and shows homology to SLP-76, a signaling element of the T cell receptor. In pervanadate/H2O2-stimulated cells, SLP-65 becomes phosphorylated only upon expression of the BCR. These data suggest that SLP-65 is part of a BCR transducer complex.
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