Current Drug Targets - Volume 13, Issue 1, 2012

G protein-coupled receptors (GPCRs) are heptaspanning membrane proteins that mediate physiological responses to a plethora of signals including hormones, neurotransmitters and exogenous sensory stimuli perceived by the senses (i.e. light, odor and taste) [1]. Classically, the mechanism by which GPCR transduce extracellular signals into cellular changes was envisaged as a plain linear model, thus the extracellular agonist ‘lig Read More

The mammalian dim-light photoreceptor rhodopsin is a prototypic G protein coupled receptor (GPCR), interacting with the G protein, transducin, rhodopsin kinase, and arrestin. All of these proteins interact with rhodopsin at its cytoplasmic surface. Structural and modeling studies have provided in-depth descriptions of the respective interfaces. Overlap and thus competition for binding surfaces is a major regulatory mec Read More

The adrenergic receptors are among the best characterized G protein-coupled receptors (GPCRs) and knowledge on this receptor family has provided several important paradigms about GPCR function and regulation. One of the most recent paradigms initially supported by studies on adrenergic receptors is that both βarrestins and G proteincoupled receptors themselves can act as scaffolds binding a variety of protein Read More

Serotonin (5-HT) is a phylogenetically ancient transmitter implicated in many vital functions in human such as sleep, food intake, reproduction, nociception, regulation of mood and emotions as well as cognitive functions. Correspondingly, dysfunction of serotonergic transmission has been implicated in numerous psychiatric disorders such as anxio-depressive states, psychoses and addiction, and serotonergic systems are ta Read More

Muscarinic acetylcholine receptors comprise a large family of G protein-coupled receptors that are involved in the regulation of many important functions of the central and peripheral nervous system. To achieve such a large range of physiological effects, these receptors interact with a large array of accessory proteins including scaffold molecules, ion channels and enzymes that operate as molecular transducers of muscarini Read More

D2 dopamine receptors (D2Rs) represent an important class of receptors in the pharmacological development of novel therapeutic drugs for the treatment of schizophrenia. Recent research into D2R signaling suggests that receptor properties are dependent on interaction with a cohort of dopamine receptor interacting proteins (DRIPs) within a macromolecular structure termed the signalplex. One component of this signalp Read More

Opiate drugs mediate their analgesic, euphoriant, and rewarding effects by activating opioid receptors. Pharmacological and molecular studies have demonstrated the existence of three opioid receptor subtypes, μ, &delta, and κ- that couple predominantly to Gi/Go types of G proteins to regulate the activity of a diverse array of effector systems. Ample experimental evidence has demonstrated that these receptors can ph Read More

G protein coupled receptors (GPCRs) play a crucial role in physiology and pathophysiology in humans. Beside the large family A (rhodopsin-like receptors) and family C GPCR (metabotropic glutamate receptors), the small family B1 GPCR (secretin-like receptors) includes important receptors such as vasoactive intestinal peptide receptors (VPAC), pituitary adenylyl cyclase activating peptide receptor (PAC1R), secretin receptor Read More

The parathyroid hormone 1 receptor (PTH1R) is activated by parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrP), hormones that mediate mineral ion homeostasis and tissue development, respectively. These diverse actions mediated by one receptor are likely due to the formation of cell-specific receptorsome complexes with cytosolic constituents. Through the second and third intracellular loo Read More

γ-aminobutyric acid type B (GABAB) receptors play a critical role in neuronal excitability and modulation of synaptic neurotransmission in the central nervous system. They are G protein-coupled receptors that signal primarily through activation of G proteins (i.e. pertussis toxin sensitive Gαi/o family) to modulate the function of inwardly-rectifying K+ and voltage-gated Ca2+ channels, and to trigger cyclic adenosine mono Read More

The correct targeting, localization, regulation and signaling of metabotropic glutamate receptors (mGluRs) represent major mechanisms underlying the complex function of neuronal networks. These tasks are accomplished by the formation of synaptic signal complexes that integrate functionally related proteins such as neurotransmitter receptors, enzymes and scaffold proteins. By these means, proteins interacting with mGluRs a Read More