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Query: EC:4.6.1.1 (
adenylate cyclase
)
19,190
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The capability of rat pituitary cells to express receptors for pituitary adenylate cyclase activating polypeptide (PACAP) and VIP was evaluated by binding studies and measurement of
adenylate cyclase
activity on whole gland preparations and by reverse transcriptase-polymerase chain reaction (TR-PCR) using specific primers on preparations from isolated cell populations enriched in PRL- and GH-producing cells. Data obtained on whole gland preparations indicated that selective PACAP receptors (PACAP Type I) predominated. The mRNA coding for PACAP Type I and for the non-selective PACAP receptors Type II
VIP2
(but not VIP1) were identified. The mRNA coding for four different spliced variants of the PACAP Type I receptor were detected. In PRL producing cells, three variants and the
VIP2
mRNA were detected, whereas in GH-producing cells the mRNA coding for the variant having a 28-amino acid insert (termed HOP) in the third intracellular loop was the only present.
...
PMID:Differential alternative splicing of PACAP receptor in pituitary cell subpopulations. 867 20
The expression of the pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal polypeptide (PACAP/VIP) receptor subtypes was evaluated in the normal rat pituitary gland and in different rat spontaneous transplantable SMtTW tumours (SMtTW2 which expresses prolactin (PRL), SMtTW10 which expresses GH and SMtTW3 which expresses both PRL and GH) by measurement of PACAP/VIP-stimulated
adenylate cyclase
activity and detection of the presence of mRNA coding for the different receptor forms. In normal glands, the order of potency of the peptides suggested that
adenylate cyclase
activity was mediated through interaction with PACAP selective receptors (PACAP I receptors); mRNAs coding for the PACAP I receptor, but also for the PACAP II VIP2 receptor, were detected. In SMtTW2 tumours, the functional response was close to that observed in the presence of PACAP II
VIP2
receptors; mRNAs coding for PACAP I and PACAP II VIP1 and PACAP II
VIP2
receptors were detected. In the SMtTW10 tumours, the functional response was complex but compatible with the involvement of PACAP I and PACAP II receptors; mRNAs coding for the PACAP I and PACAP II VIP1 receptors were detected. In the SMtTW3 tumour, the profile was similar to that of the normal pituitary gland and the mRNA coding for the PACAP I receptor only was detected. Thus, while the control of normal pituitary gland
adenylate cyclase
activity by PACAP and VIP was mediated by PACAP-selective receptors, in spontaneous transplantable tumours a variable profile was observed and PACAP, as well as VIP1 and
VIP2
receptors, may contribute to the responses.
...
PMID:Pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal polypeptide receptor subtypes are differently expressed in rat transplanted pituitary tumours (SMtTW) and in the normal gland. 878 82
Pituitary adenylate cyclase-activating polypeptide (PACAP) analogues were tested for their ability to occupy the recombinant selective PACAP receptors (PACAP type I receptors) and the non-selective PACAP-vasoactive intestinal polypeptide (VIP) receptors (PACAP type II, VIP1 and PACAP type II,
VIP2
receptors), stably transfected and expressed in Chinese hamster ovary cells. Their capacity to stimulate the
adenylate cyclase
activity was also measured. The synthetic analogues tested were peptides shortened at the carboxyl terminus by the removal of 1-4 amino acids (PACAP-26 to PACAP-23). All the peptides discriminated the 3 receptor subtypes and had the highest affinity for the VIP1 receptors, and the lowest affinity for the
VIP2
receptors; PACAP-25 having the highest ability to discriminate the VIP1 and
VIP2
receptors. All the peptides tested were full agonists on the PACAP I and VIP1 receptors; PACAP-25 and -26 were partial agonists on
VIP2
receptors and may be appropriate tools to establish the receptor subtype involved in a given cellular response.
...
PMID:C-terminally shortened pituitary adenylate cyclase-activating peptides (PACAP) discriminate PACAP I, PACAP II-VIP1 and PACAP II-VIP2 recombinant receptors. 879 75
Pituitary
adenylate cyclase
-activating peptide (PACAP) is present and synthesized in the testis in large amounts. Messenger RNA encoding the peptide is expressed in a stage specific manner in the developing germ cells. PACAP regulates a variety of physiological actions, among them, paracrine modulation of spermatogenesis. The PACAP peptides are potential ligands of at least three receptor types, the type I PACAP receptor, VIP1 and
VIP2
receptors. Although PACAP27 binding sites have found in the testis, the receptor at which it acts has not been identified. We used in situ hybridization with riboprobes to identify the PACAP binding receptor present in the testis. Neither type I PACAP receptor, nor VIP1 receptor mRNA was present within the germ cells. Using the VIP2 receptor probe there was strong labelling within some cross sections of the seminiferous tubuli, while others were not labelled. The in situ results were also confirmed using reverse-transcription PCR (RT-PCR). Our data suggest that PACAP mediates its possible paracrine effect in the testis through the VIP2 receptor.
...
PMID:PACAP acts through VIP type 2 receptors in the rat testis. 883 57
RO 25-1553 is a synthetic VIP analogue that induced a long-lasting relaxation of tracheal and bronchial smooth muscles as well as a reduction of edema and eosinophilic mobilization during pulmonary anaphylaxis. In the present study, we tested in vitro the capacity of RO 25-1553 to occupy the different VIP/PACAP receptor subclasses and to stimulate
adenylate cyclase
activity. The cellular models tested expressed one single receptor subtype: Chinese hamster ovary (CHO) cells transfected with the rat recombinant PACAP I, rat VIP1, and human
VIP2
receptors; SUP T1 cells expressing the human
VIP2
and HCT 15 and LoVo cells expressing the human VIP1 receptor. RO 25-1553 was threefold more potent than VIP on the human VIP2 receptor, 100- and 600-fold less potent than VIP on the rat and human VIP1 receptors, respectively, and 10-fold less potent than VIP and 3000-fold less potent than PACAP on the PACAP I receptor. RO 25-1553 was a full agonist on the
VIP2
, the PACAP I, and the rat recombinant VIP1 receptor but a partial agonist only on the human VIP1 receptor. Thus, RO 25-1553 is a highly selective agonist ligand for the VIP2 receptor subclass.
...
PMID:The long-acting vasoactive intestinal polypeptide agonist RO 25-1553 is highly selective of the VIP2 receptor subclass. 914 28
The biological effects of VIP are mediated by at least two VIP receptors: the VIP1 and the
VIP2
receptors that were cloned in rat, human and mice. As the mRNA coding for each receptor are located in different tissues, it is likely that each receptor modulates different functions. It is therefore of interest to obtain selective agonists for each receptor subtype. In the present work, we achieved the synthesis of two VIP1 receptor selective agonsits derived from secretin and GRF. [R16]chicken secretin had IC50 values of binding of 1,10,000, 20, and 3000 nM for the rat VIP1-,
VIP2
-, secretion- and PACAP receptors, respectively. This peptide, however, had a weaker affinity for the human VIP1 receptor (IC50 of 60 nM). The chimeric, substituted peptide [K15, R16, L27]VIP(1-7)/GRF(8-27) had IC50 values of binding of 1,10,000, 10,000 and 30,000 nM for the rat VIP1-,
VIP2
-, secretin- and PACAP receptors, respectively. Furthermore, its also showed an IC50 of 0.8 nM for the human VIP1 receptor and a low affinity for the human VIP2 receptor. It is unlikely that this GRF analogue interacted with a high affinity to the pituitary GRF receptors as it did not stimulate rat pituitary
adenylate cyclase
activity. The two described analogues stimulated maximally the
adenylate cyclase
activity on membranes expressing each receptor subtype.
...
PMID:Development of high affinity selective VIP1 receptor agonists. 943 14
A selective high affinity VIP1 receptor antagonist [Acetyl-His1, D-Phe2, Lys15, Arg16, Leu17] VIP(3-7)/GRF(8-27) or PG 97-269 was synthesized, by analogy with recently obtained selective VIP1 receptor agonists. The properties of the new peptide were evaluated on Chinese hamster ovary (CHO) cell membranes expressing either the rat VIP1-, rat
VIP2
- or the human
VIP2
-recombinant receptors and on LoVo cell membranes expressing exclusively the human VIP1 receptor. The IC50 values of 125I-VIP binding inhibition by PG 97-269 were 10, 2000, 2 and 3000 nM on the rat VIP1-, rat
VIP2
-, human VIP1- and human
VIP2
receptors, respectively. PG 97-269 had a negligible affinity for the PACAP I receptor type. It did not stimulate
adenylate cyclase
activity, but inhibited competitively effect of VIP on the VIP1 receptor mediated stimulation of
adenylate cyclase
activity. The Ki values were respectively of 15 +/- 5 nM and 2 +/- 1 nM for the rat and human VIP1 receptors. Thus the described molecule in the first reported VIP antagonist with an affinity in the nM range and with a high selectivity for the VIP1 receptor subclass. It may be useful for evaluation of the physiological role of VIP in rat and human tissues.
...
PMID:In vitro properties of a high affinity selective antagonist of the VIP1 receptor. 943 16
Stearyl vasoactive intestinal polypeptide has been reported to be a VIP (vasoactive intestinal polypeptide) receptor agonist of high potency with an original bioavailability and action. We synthesized three fatty acyl derivatives, myristyl-, palmityl- and stearyl-[Nle17]VIP, and tested their capacity to recognize recombinant rat- and human VIP1- and
VIP2
/PACAP (pituitary adenylate cyclase-activating polypeptide) receptors and to stimulate
adenylate cyclase
activity. The three lipophilic analogues bound with high affinity (from 0.5 to 20 nM) to both receptor subtypes but did not distinguish between them. In preparations expressing a high density of human VIP1/PACAP receptors, the three lipophilic analogues had the same efficacy as VIP and [Nle17]VIP. In preparations expressing the rat receptors, stearyl-[Nle17]VIP had a lower efficacy than the other peptides tested. In preparations expressing a low level of VIP1/PACAP receptors and in those expressing
VIP2
/PACAP receptors, all analogues behaved like partial agonists. The lowest efficacy was observed for stearyl-[Nle17]VIP on the
VIP2
/PACAP receptor subclass. Based on our results, a complex pattern of in vivo biological effects of the lipophilic VIP derivatives should be expected: these compounds might behave as full agonists, partial agonists, or antagonists of the VIP response, depending on the number and the subtype of receptor expressed.
...
PMID:Interaction of lipophilic VIP derivatives with recombinant VIP1/PACAP and VIP2/PACAP receptors. 972 37
The receptor subtypes involved in the relaxant effect of vasoactive intestinal polypeptide (VIP) in the rat gastric fundus were investigated in vitro. The selective VIP2 receptor agonist [Ac-H1,E8,K12,Nle17,A19,D25,L26,K27,28,G29,30,++ +T31]VIP(cyclo21-25) (RO25-1553) induced a concentration-dependent relaxation (EC50 2.8 nM), while the selective VIP1 receptor agonist derived from growth hormone-releasing factor (GRF) [K15,R16,L27]VIP-(1-7)/GRF-(8-27) had no effect up to 1 microM. [R16] chicken secretin, a selective VIP1 receptor agonist, induced relaxation with a potency of 4.8 nM but its maximal effect was clearly lower than that of VIP, pituitary
adenylate cyclase
-activating peptide [PACAP-(1-27)] and RO25-1553. This effect was reproduced by porcine secretin (EC50 2.1 nM). It is concluded that the rat gastric fundus contains functional
VIP2
receptors but not VIP1 receptors, and that specific secretin receptors are also present.
...
PMID:Influence of selective VIP receptor agonists in the rat gastric fundus. 983 Dec 96
Here we report the draft genome of Yersinia entomophaga type strain MH96T. The genome shows 93.8% nucleotide sequence identity to that of Yersinia nurmii type strain APN3a-cT, and comprises a single chromosome of approximately 4,275,531 bp. In silico analysis identified that, in addition to the previously documented Y. entomophaga Yen-TC gene cluster, the genome encodes a diverse array of toxins, including two type III secretion systems, and five rhs-associated gene clusters. As well as these multicomponent systems, several orthologs of known insect toxins, such as
VIP2
toxin and the binary toxin PirAB, and distant orthologs of some mammalian toxins, including repeats-in-toxin, a cytolethal distending toxin, hemolysin-like genes and an
adenylate cyclase
were identified. The genome also contains a large number of hypothetical proteins and orthologs of known effector proteins, such as LopT, as well as genes encoding a wide range of proteolytic determinants, including metalloproteases and pathogen fitness determinants, such as genes involved in iron metabolism. The bioinformatic data derived from the current in silico analysis, along with previous information on the pathobiology of Y. entomophaga against its insect hosts, suggests that a number of these virulence systems are required for survival in the hemocoel and incapacitation of the insect host.
...
PMID:The Draft Genome Sequence of the Yersinia entomophaga Entomopathogenic Type Strain MH96T. 2718 66
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