Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pituitary adenylate-cyclase-activating polypeptide (PACAP), a novel brain-gut hormone, was isolated from ovine hypothalami and represents the latest mammalian member of the secretin-glucagon peptide family. PACAP exists in two C-terminally amidated molecular forms, PACAP(1-27) and PACAP(1-38), comprising 27 or 38 amino acid residues, respectively. In order to identify a specific receptor for PACAP, we studied binding of 125I-labelled PACAP(1-27) to plasma membranes from rat brain. We identified a single high-affinity binding site (Kd, 340 pM and Bmax, 3.34 pmol/mg), specific for synthetic PACAP(1-38) and PACAP(1-27). Hormone binding was reversible and time, protein and temperature dependent. In contrast, neither the analogues PACAP(1-23), PACAP(18-38) and PACAP(3-25), nor vasoactive intestinal peptide (VIP), secretin and growth-hormone-releasing factor (GRF) revealed significant binding at concentrations up to 1 microM. A specific receptor protein, with an apparent molecular mass of 60 kDa, was identified by means of affinity cross-linking with disuccinimidyl suberate (DSS) and ethylene glycol disuccinimidyl suberate (EGS). PACAP receptors are associated with a GTP-binding protein as determined by the influence of different nucleotides on PACAP binding. PACAP-binding activity was solubilized with the detergents 3-[(3-cholamidopropyl)dimethylammonio]2-hydroxy-1-propane sulfonate (Chapso) or Triton X-100 and was characterized as a high-molecular-mass receptor complex (400 kDa) by non-reducing size-exclusion chromatography on Sepharose CL-6B. These data imply the following: high-affinity PACAP receptors are expressed abundantly on rat-brain plasma membranes; PACAP receptors are specific for PACAP and show no affinity for VIP, secretin and GRF; the PACAP receptor molecule has an apparent molecular mass of 60 kDa; the PACAP receptor complex is associated with a GTP-binding protein.
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PMID:Characterization of a guanosine-nucleotide-binding-protein-coupled receptor for pituitary adenylate-cyclase-activating polypeptide on plasma membranes from rat brain. 166 20

We investigated the ability of two forms of Pituitary Adenylate Cyclase Activating Polypeptide [PACAP-38, the 38 amino acid peptide isolated from ovine hypothalamus, and PACAP-27, a shorter N-terminal (1-27) amidated version] to interact with specific receptors in membranes from the human neuroblastoma cell line NB-OK. [125I]PACAP-27 bound rapidly and specifically to one class of high affinity sites (Kd 0.5 nM). VIP inhibited [125I]PACAP-27 binding 300- to 1000-fold less potently than PACAP-27 and PACAP-38. One microM PHI prevented tracer binding only partially and secretin, glucagon and GRF(1-29)NH2 were ineffective in this respect. PACAP-27 and PACAP-38 stimulated adenylate cyclase activity dose dependently and with similar efficacy (Kact 0.2-0.3 nM), this activation being compatible with the occupancy of specific high affinity PACAP receptor. VIP was markedly less potent and less efficient on this enzyme than PACAP. Chemical cross-linking of [125I]PACAP-27 followed by SDS-PAGE and autoradiography revealed specific cross-linking with a 68 kDa protein.
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PMID:The novel VIP-like hypothalamic polypeptide PACAP interacts with high affinity receptors in the human neuroblastoma cell line NB-OK. 217 43

The two forms of pituitary adenylate cyclase-activating polypeptide (PACAP), PACAP27 and PACAP38, are neuropeptide hormones related to the vasoactive intestinal peptide/secretin/glucagon family of peptides. PACAP receptors that are positively coupled to adenylyl cyclase and phospholipase C have been recently identified. We have investigated the expression of PACAP-Rs in undifferentiated and differentiated PC-12 cells. PACAP27 and PACAP38 failed to significantly increase cAMP or [3H]inositol monophosphate levels in undifferentiated PC-12 cells treated with vehicle, insulin-like growth factor I, or epidermal growth factor but greatly elevated levels after differentiation with nerve growth factor (NGF) or basic fibroblast growth factor. PACAP responsiveness increased significantly after 24 hr of NGF treatment, reaching a maximum within 4 days. At this time of differentiation, the effect of PACAP was dose dependent between 1 nM and 0.1 microM, whereas vasoactive intestinal peptide, at the maximal dose of 10 microM, slightly increased cAMP formation and failed to affect [3H]inositol monophosphate content. Radioreceptor assays, performed with 125I-PACAP27, revealed the induction of high affinity type I PACAP receptors in differentiated PC-12 cells. Using reverse transcription-polymerase chain reaction methodology, we showed the absence of type I PACAP receptor mRNAs in undifferentiated PC-12 cells and the expression of PACAP-R-hop mRNA after NGF or basic fibroblast growth factor treatment. The increased PACAP responsiveness induced by these growth factors in PC-12 cells may therefore result from the expression of the PACAP-R-hop isoform, positively coupled to both adenylyl cyclase and phospholipase C.
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PMID:Differentiation induces pituitary adenylate cyclase-activating polypeptide receptor expression in PC-12 cells. 762 75

Two types of cDNA encoding PACAP receptors were isolated from the rat brain cDNA library by homology screening with a cDNA probe for VIP receptor. Nucleotide sequence analysis indicated that these two types of receptor mRNA were generated by alternative splicing mechanisms. These two cloned cDNAs were introduced into CHO cells respectively. Resultant transformants showed specific binding to [125I]PACAP27 which was displaced by unlabeled PACAP27 but not by VIP. Thus, these receptors are two subtypes of Type I PACAP receptor (Type I-A and Type I-B). The amino acid sequences of rat PACAP receptors deduced by the cDNAs showed a remarkable similarity with rat receptors for VIP, secretin, glucagon, and GHRH. A 6.5 kb significant hybridizing signal of the PACAP receptor mRNA was detected in the rat brain, and slight signal was also detected in the lung and the liver.
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PMID:Molecular cloning and functional expression of rat cDNAs encoding the receptor for pituitary adenylate cyclase activating polypeptide (PACAP). 768 25

The expression of the messenger RNAs coding for glucagon-like peptide-I (GLP-I) receptor, VIP receptor, and pituitary adenylate cyclase-activating polypeptide (PACAP) receptor as well as the expression of the receptor proteins were demonstrated in the rat medullary carcinoma of thyroid cell line 6/23 by the following experiments: 1) RNA extraction, reverse transcriptase, and polymerase chain reaction with specific primers; 2) binding of the radiolabeled ligands [125I]GLP-I-(7-36)-NH2, [125I]PACAP-(1-27), and [125I]VIP and inhibition by, respectively, unlabeled GLP-I-(7-36)-NH2, PACAP-(1-27), and VIP; and 3) study of adenylate cyclase activation by the peptides and selective inhibition of the VIP/PACAP response by the antagonist [D-Phe2]VIP. Besides the highly selective GLP-I receptor, PACAP receptors of types I and II were present on the cell line and coupled to adenylate cyclase. PACAP stimulated the adenylate cyclase through type I and II receptors, whereas VIP interacted with type II receptors only. Messenger RNA analysis indicated that at least three splice variants of the PACAP type I receptor may be expressed in 6/23 cells.
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PMID:Pituitary adenylate cyclase-activating polypeptide receptors of types I and II and glucagon-like peptide-I receptors are expressed in the rat medullary carcinoma of the thyroid cell line 6/23. 792 14

A cDNA encoding a pituitary adenylate cyclase-activating polypeptide (PACAP) receptor was cloned from a bovine brain cDNA library using a synthetic oligonucleotide probe corresponding to the partial N-terminal amino acid sequence of the PACAP receptor purified from the bovine brain. The cloned cDNA encoded a polypeptide of 513 amino acid residues with seven putative transmembrane domains. The deduced amino acid sequence exactly matched the N-terminal amino acid sequence of the purified PACAP receptor. It also shared an apparent similarity with the vasoactive intestinal peptide (VIP), secretin, growth hormone releasing hormone, calcitonin, and glucagon receptors, suggesting that the PACAP receptor is a member of the secretin receptor subfamily of the guanine nucleotide-binding regulatory protein-coupled receptor family. Northern blot analysis showed that the size of the major mRNA band which hybridized with the cDNA was about 7 kb in the bovine cerebral-cortex and hippocampus. An expression vector containing the cloned cDNA for the PACAP receptor was introduced into Chinese hamster ovary (CHO) cells. The affinity of PACAP receptors expressed on the transfected CHO cells was quite similar to that of natural PACAP receptors on the bovine brain membranes. Competitive binding experiments showed that PACAP38 displaced the binding of 125I-labeled PACAP27 to the receptors on the CHO cells more efficiently than PACAP27, while VIP was less effective. In addition, both of PACAP27 and PACAP38 elevated the levels of cAMP and inositol phosphates in the transformed CHO cells. These results indicate that the PACAP receptors encoded by the cloned cDNA are identical to the purified PACAP receptors, and that they can stimulate dual signaling cascades.
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PMID:Cloning and expression of a complementary DNA encoding the bovine receptor for pituitary adenylate cyclase-activating polypeptide (PACAP). 804 55

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide belonging to the vasoactive intestinal polypeptide/glucagon/secretin family. It is widely distributed in the body, and a variety of biological actions have been reported. PACAP exerts its biological effects by binding to specific receptors that are coupled to GTP-binding proteins. Recent studies have shown that there is a family of PACAP receptors (PACAPRs), and two members of this family have been identified. We report here the cloning, functional expression, and tissue distribution of a third PACAPR subtype, designated PACAPR-3. The cDNA encoding PACAPR-3 has been isolated from a mouse insulin-secreting beta-cell line MIN6 cDNA library. Mouse PACAPR-3 is a protein of 437 amino acids that has 50% and 51% identity with rat PACAP type I and type II receptors, respectively. Expression of recombinant mouse PACAPR-3 in mammalian cells shows that it binds to vasoactive intestinal polypeptide as well as PACAP-38 and -27, with a slightly higher affinity for PACAP-38, and is positively coupled to adenylate cyclase. The expression of PACAPR-3 in Xenopus oocytes indicates that calcium-activated chloride currents are evoked by PACAP and vasoactive intestinal polypeptide, suggesting that PACAPR-3 can also be coupled to phospholipase C. RNA blot analysis studies reveal that PACAPR-3 mRNA is expressed at high levels in MIN6, at moderate levels in pancreatic islets and other insulin-secreting cell lines, HIT-T15 and RINm5F, as well as in the lung, brain, stomach, and colon, and at low levels in the heart. Furthermore, insulin secretion from MIN6 cells is significantly stimulated by PACAP-38. These results suggest that the diverse biological effects of PACAP are mediated by a family of structurally related proteins and that PACAPR-3 participates in the regulation of insulin secretion.
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PMID:Cloning and functional characterization of a third pituitary adenylate cyclase-activating polypeptide receptor subtype expressed in insulin-secreting cells. 814 74

Pituitary adenylate cyclase-activating polypeptide (PACAP), a neuropeptide belonging to the vasoactive intestinal peptide (VIP)/secretion/glucagon family of peptides, interacts with a distinct high-affinity receptor (type I receptor) on a number of tissues. These PACAP type I receptors have a high affinity for PACAP and a low affinity for VIP and are present in the hypothalamus and anterior pituitary, where they regulate the release of adrenocorticotropin, luteinizing hormone, growth hormone, and prolactin, and in the adrenal medulla, where they regulate the release of epinephrine. Type I PACAP receptors are also present in high concentrations in testicular germ cells, where they may regulate spermatogenesis, and some transformed cell lines, such as the rat pancreatic acinar carcinoma cell AR4-2J. Here we report the molecular cloning and functional expression of the PACAP type I receptor isolated from an AR4-2J cell cDNA library by cross-hybridization screening with a rat VIP receptor cDNA. The cDNA sequence encodes a unique 495-amino acid protein with seven transmembrane domains characteristic of guanine nucleotide-binding regulatory protein-coupled receptors. A high degree of sequence homology with the VIP, secretin, glucagon-like peptide 1, parathyroid, and calcitonin receptors suggests its membership in this subfamily of Gs-coupled receptors. Results of binding studies and stimulation of cellular cAMP accumulation in COS-7 cells transfected with this cDNA are characteristic of a PACAP type I receptor. Cloning of the PACAP type I receptor will enhance our understanding of its distribution, structure, and functional properties and ultimately increase our understanding of its physiological role.
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PMID:Molecular cloning and functional expression of the pituitary adenylate cyclase-activating polypeptide type I receptor. 839 97

Pituitary adenylate cyclase-activating polypeptide (PA-CAP) is a polypeptide hormone related to vasoactive intestinal polypeptide (VIP). Rat PACAP receptor cDNA was isolated from a brain cDNA library by cross-hybridization with rat VIP receptor cDNA. The recombinant PACAP receptor expressed in COS cells bound PACAP with about 1000 times higher affinity than VIP, and PACAP stimulated adenylate cyclase through the cloned PACAP receptor. The rat PACAP receptor consists of 495 amino acids, contains seven transmembrane segments, and has a significant similarity with other Gs-coupled receptors, such as VIP, glucagon, and secretin receptors. PACAP receptor mRNA was abundantly expressed in the brain, but not in the peripheral tissues except for the adrenal gland. In situ hybridization revealed a high level of expression of PACAP receptor mRNA in the hippocampal dentate gyrus, olfactory bulb, and cerebellar cortex.
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PMID:Molecular cloning and tissue distribution of a receptor for pituitary adenylate cyclase-activating polypeptide. 839 23

The two forms of pituitary adenylyl cyclase-activating polypeptide (PACAP-27 and -38) are neuropeptides of the secretin/glucagon/vasoactive intestinal polypeptide/growth-hormone-releasing hormone family and regulate hormone release from the pituitary and adrenal gland. They may also be involved in spermatogenesis, and PACAP-38 potently stimulates neuritogenesis and survival of cultured rat sympathetic neuroblast and promotes neurite outgrowth of PC-12 cells. The PACAP type-I receptor (found in hypothalamus, brain stem, pituitary, adrenal gland and testes), specific for PACAP, is positively coupled to adenylyl cyclase and phospholipase C. The recently cloned type II receptor does not discriminate between PACAP and vasoactive intestinal polypeptide and is coupled to only adenylyl cyclase. Here we have used a new expression cloning strategy, based on the induction of a reporter gene by cyclic AMP, to isolate a complementary DNA encoding the type-I PACAP receptor. On transfection of this cDNA, both PACAP-27 and -38 stimulate adenylyl cyclase with similar EC50 values (50% effective concentration, 0.1-0.4 nM), whereas only PACAP-38 stimulates phospholipase C with high potency (EC50 = 15 nM). Four other splice variants were isolated with insertions at the C-terminal end of the third intracellular loop. Expression of these cDNAs revealed altered patterns of adenylyl cyclase and phospholipase C stimulation, suggesting a novel mechanism for fine tuning of signal transduction.
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PMID:Differential signal transduction by five splice variants of the PACAP receptor. 839 27


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