Death receptor signaling and XXXX .

@entity1 @entity32 @entity5 @entity19 @entity74 @entity204 @entity792
In recent years, it has become clear that self-nonself discrimination by the immune system is driven not so much by the specificities of the antigen receptors themselves, but by ligand-receptor systems that sense the presence of foreign pathogens (toll-like receptors) and those that regulate the balance between cellular proliferation and programmed cell @entity204 ( @entity5 necrosis factor [TNF] family ligands and receptors). Interestingly, these two receptor families share a number of common signaling pathways, mediated by the cytoplasmic proteins containing @entity204 domains and TRAF domains, which trigger the complementary processes of programmed cell @entity204 and @entity32 . Both @entity1 and @entity19 with @entity74 in the TNF-receptor family member Fas accumulate abnormal lymphocytes and develop systemic @entity792 . These findings highlighted the importance of this TNF-receptor family member in the homeostasis of the immune system. In particular, the Fas receptor has been shown to be important in immunoreceptor-mediated apoptosis of activated T and B lymphocytes. Six members of the TNF-receptor superfamily share a common signaling domain with Fas, termed the @entity204 domain, that directly links these receptors to the apoptotic machinery of the cell, and, collectively, these receptors have been designated as " @entity204 receptors."We are currently investigating a number of important unresolved issues in this field, including: (1). how susceptibility to apoptosis through @entity204 receptors is regulated, (2). how Fas and related @entity204 receptors function in the maintenance of self-tolerance and homeostasis in the major cell types of the immune system, and (3). recently described nonapoptotic lymphocyte activation signals that use components of @entity204 receptor signaling.
