The kinase Syk as an adaptor controlling sustained calcium signalling and B-cell development

Upon B-cell antigen receptor (BCR) activation, the protein tyrosine kinase Syk phosphorylates the adaptor protein SH2 domain-containing leukocyte protein of 65 kDa (SLP-65), thus coupling the BCR to diverse signalling pathways. Here, we report that SLP-65 is not only a downstream target and substrate of Syk but also a direct binding-partner and activator of this kinase. This positive feedback is mediated by the binding of the SH2 domain of SLP-65 to an autophosphorylated tyrosine of Syk. The mutant B cells that cannot form the Syk/SLP-65 complex are defective in BCR-induced extracellular signal-regulated kinase, nuclear factor κ B and nuclear factor of activated T cells, but not Akt activation, and are blocked in B-cell development. Furthermore, we show that formation of the Syk/SLP-65 complex is required for sustained Ca2+ responses in activated B cells. We suggest that after activation and internalization of the BCR, Syk remains active as part of a membrane-bound Syk/SLP-65 complex controlling sustained signalling and calcium influx

Personalized diagnosis and therapy.

Personalized medicine, i.e., the use of information about a person’s genes, proteins, metabolites, and environment to prevent, diagnose, and treat disease, has been much talked about in recent years. So some observers are wondering what the excitement is all about cumulating in the following statement: “Personalized health care is nothing new. Doctors have always tried to fit the therapy to the patient’s need if possible.” But what has happened more recently is that one has now begun to go a level deeper, i.e., to explore the biology of the disease and its treatment at the molecular level. However, molecular medicine does not per se define personalized medicine, but the molecular tools are important as they should enable greater relevance in the information provided by corresponding diagnostic tests (see below) (Edwards et al. 2008; Weedon et al. 2006; Romeo et al. 2007; Hegel et al. 1999; Wildin et al. 2001; Grant et al. 2006; Rothman and Greenland 2005; Raeder et al. 2006; Hegele et al. 2000; Capell and Collins 2006; Delepine et al. 2000; Janssens et al. 2006; Xiayan and Legido-Quigley 2008; Figeys and Pinto 2001; Müller 2002, 2010; Pearson et al. 2007; Janssens et al. 2008; Risch and Merikangas 1996; Janssens and van Duijn 2008; McCarthy 2003; McCarthy et al. 2003; Stumvoll et al. 2005; Lyssenko et al. 2005; Florez et al. 2003)