A new family of regulators of G-protein-coupled receptors?

Organisms as diverse as fungi and humans use G-protein-coupled receptors to control signal transduction pathways responsive to various hormones, neuroregulatory molecules and other sensory stimuli [1]. Continual stimulation of these receptors often leads to their desensitization, which is mediated in part by the consecutive actions of two families of proteins - the G-protein-coupled receptor kinases, which phosphorylate the agonist-occupied receptors [2], and the arrestin proteins, which subsequently bind to the receptors [3]. We now present evidence that a group of proteins - the GOS8/Sst2p family - may be a third class of receptor-desensitizing factors.