Cell Line

The prolactin releasing hormone receptor PRLHR also named PrRP receptor is a G-protein coupled receptor that binds the prolactin releasing hormone. RT-PCR analysis showed expression of PRLHR in the human brain, pituitaries, normal portions of adrenal glands and various tumor tissues. Northern blot analysis showed high expression of PRLHR only in tumor tissues of pheochromocytomas, indicating that PRLHR expression is high in pheochromocytomas. The present study has shown that PRLHR mRNA was widely expressed in the brain tissues, pituitaries, adrenal glands and various tumors. The high expression of PRLHR receptor in pheochromocytomas suggests potential pathophysiological roles of PRLHR in these tumors

The widespread neuropeptide vasoactive intestinal peptide (VIP) has two receptors VPAC1 and VPAC2. The vasoactive intestinal polypeptide receptor VPAC1 is G_s-coupled GPCRs expressed in the lung, prostate, peripheral blood leukocytes, liver, brain, small intestine colon, heart, spleen, placenta, kidney, thymus, and testis.

The CRF1 receptor is a Gs-coupled GPCR expressed in the brain and pituitary gland that binds to several neuropeptides, including corticotropin-releasing factor (CRF) and urocortin, and the amphibian peptide sauvagine. CRF plays a predominant role in stress response mediated by the hypothalamic-pituitary-adrenal axis, and alterations in CRF and its receptors CRF1 and CRF2 appear to be linked to depression and anxiety. In comparison to the CRF2 receptor, the CRF1 receptor has received considerable attention as a potential therapeutic target for the treatment of stress-related disorders such as adrenocorticotropin hypersecretion, increased colonic motility and exaggerated fear and anxiety-related behavior.

The NPS receptor is a typical GPCR, also known as GPR154, vasopressin-receptor related receptor 1 (VRR1), or GPRA. NPSR was found mainly expressed in the central nervous system of rats by using in-situ hybridization. NPS receptor mRNA is widely distributed in many brain areas with high expression levels in cortex, hypothalamus, amygdala and multiple midline thalamic nuclei. Many of these areas have been functionally associated with arousal and processing of emotional behavior. In 2004, the NPS receptor was identified as an asthma susceptibility gene in a genome wide screen in Finnish and Canadian patients. The study showed that a number of polymorphic variants of the NPS receptor exist in human and that particular sets of these variants (haplotypes) are associated with an increased risk of asthma and possibly allergic diseases characterized by high IgE serum levels. A carboxy-terminal splice variant of human NPS receptor was found to be over-expressed in asthmatic airway tissue.

Glucagon regulates blood glucose via control of hepatic glycogenolysis and gluconeogenesis and via regulation of insulin release from the β cell. Pharmacological administration of glucagon increases blood glucose in normal and diabetic subjects, and produces positive inotropic and chronotropic cardiovascular effects, relaxation of smooth muscle in the gastrointestinal tract and stimulation of growth hormone secretion. The actions of glucagon are mediated via a single adenylate cyclase-coupled glucagon receptor that also couples to the phospholipase C-inositol phosphate (PLC-IP) pathway leading to Ca²⁺ release from intracellular stores.

The motilin receptor (MTLR) represents a clinically useful pharmacological target, as agonists binding to the MTLR have gastroprokinetic properties. Motilin is a 22 amino acid peptide that potently stimulates gastrointestinal contractility. The biological effects of motilin are mediated by a G_q-coupled seven transmembrane protein, currently termed motilin receptor (MR) that shares significant sequence similarity with the ghrelin receptor. The motilin receptor is also activated by the antibiotic erythromycin; this interaction appears to mediate some of the gastrointestinal side effects of erythromycin. Although motilides (non-antibiotic derivatives of erythromycin) such as ABT-229 have been investigated for treatment of diabetic gastroporesis, the effectiveness has been limited by tachyphylaxis (decreased response to ligand) resulting from receptor downregulation. Agonists of the motilin receptor with reduced densensitization activity remain a potential treatment for dis

Glucagon regulates blood glucose via control of hepatic glycogenolysis and gluconeogenesis and via regulation of insulin release from the β cell. Pharmacological administration of glucagon increases blood glucose in normal and diabetic subjects, and produces positive inotropic and chronotropic cardiovascular effects, relaxation of smooth muscle in the gastrointestinal tract and stimulation of growth hormone secretion. The actions of glucagon are mediated via a single adenylate cyclase-coupled glucagon receptor that also couples to the phospholipase C-inositol phosphate (PLC-IP) pathway leading to Ca²⁺ release from intracellular stores.

Melatonin binds to two specific G-protein coupled receptors (GPCR), MT1 (MTNR1A/MEL1A) and MT2 (MTNR1B/MEL1B). MT1 receptors signal via inhibitory G proteins (Gα_i and Gα_o) leading to adenylate cyclase inhibition and possibly inositol phosphate stimulation in recombinant systems. In certain native tissues (e.g. sheep pars tuberalis, rat cerebral and caudal arteries) melatonin responses are presumably mediated through activation of MT1 receptors. The hypothalamic suprachiasmatic nucleus appears to be involved in circadian rhythm while the hypophysial pars tuberalis may be responsible for the reproductive effects of melatonin.

Recombinant CHO-K1 cells stably overexpress mas-related G-protein coupled receptor member X2 (MRGPRX2). MRGPRX2 couples to both Gi and Gq alpha subunits in mast cells naturally, so that the PLC signaling can be triggered within the cells by agonist binding. This cell line is recommended for agonist screening and functional validations with calcium flux assay.