Module 1: Figure homologous desensitization
Homologous desensitization and down-regulation of G protein-coupled receptors (GPCRs).
Homologous desensitization has two components. Receptor desensitization occurs soon after agonist stimulation through a sequence of reactions that are readily reversible (Steps 1–4 in hatched box on the left). If agonist stimulation persists, receptor down-regulation occurs when the receptors are internalized (Steps 5–8 in hatched box on the right). The receptors that enter the clathrin-coated pits are either recycled or degraded. See text for further details.