In cellular biology, dependence receptors are proteins that mediate programmed cell death by monitoring the absence of certain trophic factors (or, equivalently, the presence of anti-trophic factors) that otherwise serve as ligands (interactors) for the dependence receptors.A trophic ligand is a molecule whose protein binding stimulates cell growth, differentiation, and/or survival.Cells depend for their survival on stimulation that is mediated by various receptors and sensors, and integrated via signaling within the cell and between cells. The withdrawal of such trophic support leads to a form of cellular suicide.