Birgitte Holst

TL;DR: It is concluded that the ghrelin receptor is highly constitutively active and that this activity could be of physiological importance in its role as a regulator of both GH secretion and appetite control.

TL;DR: It is concluded that GPR39 is probably not the obestatin receptor and the potency and efficacy of Zn(2+) in respect of activating signaling indicates that this metal ion could be a physiologically relevant agonist or modulator of G PR39.

TL;DR: A global toggle switch model is proposed for this activation mechanism to reconcile the accumulated biophysical data supporting an outward rigid-body movement of the intracellular segments, as well as the recent data derived from activating metal ion sites and tethered ligands, which suggests an opposite, inward movement ofthe extracellular segments of the transmembrane helices.

TL;DR: These structures demonstrate that the main ligand-binding pocket in 7TM receptors is like a funnel with a partial 'lid' in which extracellular loop 2b, in particular, functions as a gating element.

TL;DR: It is concluded that the three ghrelin-like receptors display an unusually high degree of constitutive activity, the structural basis for which is determined by an aromatic cluster on the inner face of the extracellular ends of TMs VI and VII.