Receptors on phaeochromocytoma cells for two members of the PP‐fold family — NPY and PP

102

Pancreatic polypeptide (PP) is produced in the islets of Langerhans and released in response to meals. It belongs to a family of peptides that also includes neuropeptide Y and peptide YY. In the present communication, we describe a rat receptor with high affinity for PP, therefore named PP1. Clones for the PP1 receptor were obtained by PCR using sequence information for the neuropeptide Y receptor Y1 from several species. The PP1 receptor has 46% overall amino acid sequence identity to the rat Y1 receptor and 56% identity in the transmembrane regions. The PP1 receptor displays a pharmacological profile that is distinct from previously described neuropeptide Y-family receptors. In competition with iodinated bovine PP, it binds rat PP with an affinity (K*) of 0.017 nM, while the affinities for peptide YY and neuropeptide Y are substantially lower with K; values of 162 and 192 nM, respectively. In stably transfected CHO cells, the PP1 receptor inhibits forskolin-stimulated cAMP synthesis. Northern blot hybridizations to a panel of mRNAs detected transcripts in testis and lung. A faint band was seen in colon and total brain. In contrast, the human receptor is expressed primarily in colon and small intestine. Whereas rat and human PP1 bind PP with the same affinity, the rat receptor has much lower affinity than its human ortholog for peptide YY and neuropeptide Y. Interestingly, the amino acid sequence identity between rat and human PP1 is only 75%. Thus, the sequence, the tissue distribution, and the binding profile of the PP1 receptor differ considerably between rat and human.The pancreatic polypeptide (PP)-fold family of neuroendocrine peptides consists of PP, neuropeptide Y (NPY), and peptide YY (PYY). All three peptides have 36 aa and share prominent sequence and three-dimensional structure similarity (1). PP is s.creted from pancreatic islets in response to meals, and it inhibits gall bladder contraction, gut motility, and pancreatic secretion (for review, see ref.2). PP has also been isolated from porcine intestine (3). PYY is found in endocrine cells of the lower intestine (4) as well as in pancreatic islets (5) and a few neuronal populations (6, 7). Its release and actions on the gastrointestinal tract are similar to those of PP (see ref.2). NPY, in contrast, is found in the central and peripheral nervous systems. All three peptides have been found in animal experimentsto increase food intake. NPY is considered to be one of the most potent orexigenic substances known (8), and intracerebroventricular injection of PP stimulates feeding in rats, mice, and dogs (9-12). Anorectic patients have high levels of circulating PP (13,14), whereas obese persons have decreased PP concentrations (15)

Section: All Three Peptides Have Been Found In Animal Experimentsmentioning

confidence: 99%

The cloned rat pancreatic polypeptide receptor exhibits profound differences to the orthologous receptor.

Lundell

Statnick

Johnson

et al. 1996

102

“…All of these peptides consist of 36 amino acids and have a carboxyl-terminal amide. Porcine NPY and PYY show 70% sequence identity and can act on the same receptors with similar potencies (6), whereas porcine PP is only 50% identical to NPY and PYY and appears to have distinct receptors (7)(8)(9). PP differs considerably between species; PP of pig, chicken, and bullfrog share only 44-58% identity.…”

mentioning

confidence: 99%

Strong evolutionary conservation of neuropeptide Y: sequences of chicken, goldfish, and Torpedo marmorata DNA clones.

Blomqvist

Söderberg²,

Lundell³

et al. 1992

178

Neuropeptide Y (NPY) is an abundant and widespread neuropeptide in the nervous system of mammals. NPY belongs to a family of 36-amino acid peptides that also includes pancreatic polypeptide and the endocrine gut peptide YY as well as the fish pancreatic peptide Y. To study the evolution of this peptide family, we have isolated clones encoding NPY from central nervous system cDNA libraries of chicken, goldfish, and the ray Torpedo marmorata, as well as from a chicken genomic library. The predicted chicken NPY amino acid sequence differs from that of rat at only one position. The goldfish sequence differs at five positions and shows that bony fishes have a true NPY peptide in addition to their pancreatic peptide Y. The Torpedo sequence differs from that of rat at three positions. As Torpedo NPY has no unique positions when compared with the other sequences, it seems to be identical to the NPY of the common ancestor ofcartilaginous fishes, bony fishes, and tetrapods after 420 million years of evolution. The 30-amino acid carboxyl-terminal extension of the NPY precursor also displays considerable sequence conservation. These results show that NPY is one ofthe most highly conserved neuroendocrine peptides.Neuropeptide Y (NPY) was first purified from porcine brain (1). The name is derived from its amino-and carboxylterminal tyrosines (single-letter code Y). Subsequently, NPY sequences have been determined for six other mammals (2) and for a frog (3), revealing a remarkable degree of conservation. NPY occurs abundantly in the mammalian central nervous system as well as in the peripheral nervous system (4) and has been shown to have both pre-and postsynaptic actions (5).NPY belongs to a family of peptides that includes the gut endocrine peptide YY (PYY) and the pancreatic endocrine peptides called pancreatic polypeptide (PP) in tetrapods and peptide tyrosine (PY) in fish. All of these peptides consist of 36 amino acids and have a carboxyl-terminal amide. Porcine NPY and PYY show 70% sequence identity and can act on the same receptors with similar potencies (6), whereas porcine PP is only 50% identical to NPY and PYY and appears to have distinct receptors (7-9). PP differs considerably between species; PP of pig, chicken, and bullfrog share only 44-58% identity.Pancreatic peptides have been isolated and sequenced from four different species of fish (2). Surprisingly, these peptides were found to be more similar to mammalian NPY and PYY than to PP. Because of the unclear relationships with the mammalian peptides, the fish pancreatic peptides have been given different names by different groups of investigators. We use here the designation PY.Immunohistochemical studies of NPY, PYY, and PP have been interpreted to indicate that PP appeared first in evolution (10), and sequence and receptor-binding analyses have suggested that PP forms one evolutionary lineage whereas NPY and PYY form a separate lineage and diverged from each other more recently (11). To extend the structural evolutionary analyses, we decided to isol...

“…PP has negligible affinity for Y1, Y2, and Y3 receptors, but high-affinity PP receptors that do not recognize NPY or PYY have been described on rat pheochromocytoma (PC12) cells and in rat brainstem (3,21). The present study describes the cloning and functional expression of human and rat PP receptors from brain cDNA libraries.…”

mentioning

confidence: 99%

Cloning and functional expression of cDNAs encoding human and rat pancreatic polypeptide receptors.

Yan

Yang

Marasco

et al. 1996

PCR was used to isolate nucleotide sequences that may encode novel members of the neuropeptide Y receptor family. By use of a PCR product as a hybridization probe, a full-length human cDNA was isolated that encodes a 375-aa protein with a predicted membrane topology identifying it as a member of the G-protein-coupled receptor superfamily. After stable transfection of the cDNA into human embryonic kidney 293 cells, the receptor exhibited high affinity (Kd = 2.8 nM) for 1251-labeled human pancreatic polypeptide (PP).Competition binding studies in whole cells indicated the following rank order of potency: human PP = bovine PP 2 human [Pro34] peptide YY > rat PP > human peptide VY = human neuropeptide Y. Northern blot analysis revealed that human PP receptor mRNA is most abundantly expressed in skeletal muscle and, to a lesser extent, in lung and brain tissue. A rat cDNA clone encoding a high-affinity PP receptor that is 74% identical to the human PP receptor at the amino acid level was also isolated. These receptor clones will be useful in elucidating the functional role of PP and designing selective PP receptor agonists and antagonists.Pancreatic polypeptide (PP), peptide YY (PYY), and neuropeptide Y (NPY) are C-terminal amidated, 36-aa peptides that constitute the mammalian NPY family (1). PP is produced predominantly by pancreatic islet cells and regulates pancreatic exocrine secretion through a mechanism that is not fully understood but may involve inhibition of vagal input to the pancreas (2, 3). PYY-like immunoreactivity is found in endocrine cells of the lower gastrointestinal tract, and the peptide has been shown to have a variety of effects on gastrointestinal function (4, 5). NPY, which is the most highly conserved of the family members between species (6), is extensively distributed throughout both the central and the peripheral nervous systems (7,8). NPY is colocalized with norepinephrine in postganglionic sympathetic nerves (4) and is a potent vasopressor agent (9). The observations of persistent vasoconstriction after a-adrenergic receptor blockade (10, 11) and elevated levels of NPY in hypertensive patients (10, 12) suggest a possible role for NPY in the pathophysiology of hypertension. In the central nervous system, NPY immunoreactivity and mRNA are prevalent in various hypothalamic nuclei, the cerebral cortex, and the septal-hippocampal system and striatum (5). Important effects of centrally administered NPY include hyperphagia (13), anxiolysis (14), and regulation of pituitary hormone release (15).Receptors for NPY/PYY have been delineated on the basis of pharmacological selectivity exhibited by certain tissues and cell lines. The Y1 receptor exhibits high affinity for NPY, PYY, and C-terminal-substituted variants, including [Leu3t,Pro34]NPY, but low affinity for long C-terminal fragments such as 17). This receptor, which is a member of the G-protein-coupled receptor superfamily, has been cloned (18), and its pharmacological properties in transfected cells are identical to those of Y1 rece...