Interactions between TNF family receptors. (A) Stem and progenitor cells; (B) the differentiated progeny. The impact of receptor ligation by the cognate ligands and crosstalk are presented in reference to proliferation, induced expression, apoptosis, survival, and trophic signaling. Joint activation of Fas/TNF-R1 and Fas/TRAIL-R1 results in superior survival, with dominant influence of the TNFα and TRAIL receptors.