Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stimulated hydrolysis of inositol lipids and phosphatidylcholine (PtdCho) by bombesin, [Arg8]vasopressin ([Arg8]Vp) and prostaglandin F2 alpha (PGF2 alpha) was analysed in Swiss 3T3 cells pre-labelled to isotopic equilibrium with either [methyl-3H]choline, myo-[2-3H]inositol or [9,10 (n)-3H]palmitic acid. All three agonists activated the phospholipase D-catalysed hydrolysis of PtdCho as determined by the release of [3H]choline (Cho) and the formation of [3H]phosphatidylbutanol (PtdBut). The release of [3H]choline by each agonist exhibited similar sensitivity to prolonged pre-exposure to the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). The release of [3H]choline exhibited the same dose dependency as the production of total inositol phosphates for each mitogen suggesting that the two responses might be mediated through identical receptors. Acute pre-treatment with TPA allowed the dissociation of inositol lipid hydrolysis from PtdCho breakdown, since it inhibited inositol phosphate accumulation but stimulated choline generation. The loss of mitogen stimulated choline release in cells pre-treated with the phorbol ester for 48 h was not due to loss of stimulated inositol phosphate production which was reproducibly enhanced in these 'down-regulated' cells.
 ...
PMID:Hydrolysis of phosphatidylcholine by phospholipase D is a common response to mitogens which stimulate inositol lipid hydrolysis in Swiss 3T3 fibroblasts. 201 90

Phospholipase D belongs to a group of membrane associated phospholipases which have been shown to be activated by G-protein coupled neurotransmitter receptors. Phosphatidylcholine is the primary substrate for phospholipase D generating phosphatidic acid (PA) and choline. In the presence of 1% ethanol, phospholipase D catalyzes a transphosphatidylation reaction generating phosphatidylethanol (PEt) which is an indicator of phospholipase D activation. In the present study, we utilized Chinese hamster ovary (CHO) cells stably transfected with and expressing a rat V1a vasopressin receptor to study the regulation of phospholipase D by protein kinase C and calcium. Arginine-vasopressin (AVP) stimulated the release of 3H-PEt and 3H-PA in cells pre-labelled overnight with 3H-palmitic acid. The phorbol ester, phorbol 12-myristate 13-acetate (PMA), stimulated the release of PEt and PA that was additive with AVP over 15 min. However, long-term stimulation with PMA, which desensitizes protein kinase C, decreased PEt production while simultaneously increasing PA production. Differential regulation of PEt and PA production by PMA suggests the existence of more than one phospholipase D isoenzyme. Though differentially regulated by protein kinase C, both AVP-stimulated PEt and PA production required extracellular and not intracellular calcium.
 ...
PMID:Vasopressin Vla receptor-stimulated phospholipase D: differential regulation of transphosphatidylation and phospholipid hydrolysis by protein kinase C [corrected]. 760 88

In rats the PAM specific activity in hypothalamic and neurohypophyseal extracts was 0.58 +/- 0.8, respectively 1.78 +/- 0.6 nmol.mg prot.-1 x h-1 (n = 5). PHM specific activity in the soluble part of the granules was higher in the neurohypophyseal than in the hypothalamic granules, and the fraction of total PHM and PAL present in the soluble part increased with the distance from the hypothalamus from some 45% to approx. 85%. Western blots of membrane and soluble granule fractions showed prevalence of higher mol. wt. forms in hypothalamic granules. It would appear that higher mol. wt. forms of PAM are processed by proteolytic enzymes during transport in the neuron and that non-neural cells in the neurohypophysis have a considerable PAM activity.
 ...
PMID:Amidating processing enzyme complex for bioactive peptides (PAM) shows differences in specific activity and form in secretory granules isolated from the proximal and distal parts of the hypothalamo-neurohypophyseal tract in rats. 840 76

Palmitoylation of the V2 vasopressin receptor (V2R) and its functional role were investigated in transfected cells. Palmitoylation was assessed by incubating transfected cells with [3H]palmitic acid and immunoprecipitating the receptor with an antibody raised against a portion of the third intracellular loop of V2R. Wild-type and nonglycosylated V2R yielded tritium signals at 45-55 and 40 kDa, respectively, demonstrating that the V2R is palmitoylated and that receptor palmitoylation is independent of glycosylation. Substitution of CC341/342 for serines eliminated receptor palmitoylation, whereas replacement of a single amino acid, C341S or C342S, restored partial palmitoylation. Saturation binding assays revealed decreased cell surface expression of the nonpalmitoylated receptor compared with the wild-type; this effect was more pronounced when a truncated form of V2R (G345ter) was studied. The presence of either cysteine residue (C341S or C342S) elevated receptor expression to normal levels, most likely due to the partial restoration of palmitoylation. Ligand binding affinity, hormone-induced stimulation of adenylyl cyclase activity, receptor internalization, and desensitization were not affected by the absence of palmitoylation. No increase but rather a slight decrease in the extent of receptor palmitoylation was detected after exposure to vasopressin. It was concluded that the V2R is palmitoylated in both cysteines, each cysteine is palmitoylated independently from the other, and palmitoylation enhances cell surface expression of the V2R.
 ...
PMID:Palmitoylation of the V2 vasopressin receptor. 922 8

Synthesis, processing and agonist-induced modifications of the V2 vasopressin receptor were examined in stably or transiently transfected HEK293 cells. Metabolic labeling with S methionine for 30 min revealed a predominant precursor protein which subsequently gave rise to the mature receptor on the cell surface. Maturation of the receptor was unrelated to glycosylation suggesting that it was the consequence of protein refolding. In addition to monomeric forms of V2 receptor protein, oligomers of the precursor protein were also detected in SDS-PAGE. These oligomers seemed to be dimers and tetrameres, and were more apparent in transiently transfected cells that produced higher quantities of protein then stably transfected cells. No oligomers of the mature receptor were detected, and co-transfection of the wild type with a mutant V2 receptor lacking G-protein coupling activity did not alter the function of the wild type receptor. These results indicated that the formation of oligomeric was most likely a consequence of overproduction of the protein and not a required step for receptor function. Addition of vasopressin promoted phosphorylation and sequestration of the wild type receptor, and of the R137H mutant receptor which lacks coupling to G proteins. Activation of protein kinases A or C did not result in phosphorylation of un-occupied receptor. Phosphate incorporated into the protein was stable in the continuous presence of the ligand despite sequestration of the receptor protein. Deletion of the last 14 amino acids abolished receptor phosphorylation but not sequestration and desensitization, indicating that these two processes are not dependent on protein phosphorylation. Additionally, phosphorylation and sequestration of the R137H mutant receptor revealed that phosphorylation and sequestration does not require coupling to Gs. The wild type V2 vasopressin receptor was found to be palmitoylated at two cysteines at the carboxyl terminus. Either cysteine could be palmitoylated independently of each other and the presence of at least one was required to obtain receptor expression similar to the wild type. The turnover of the palmitic acid incorporated into the receptor was not altered by the addition of vasopressin demonstrating that this post-translational modification of the receptor was not altered by the ligand-promoted phosphorylation of the protein.
 ...
PMID:Processing and ligand-induced modifications of the V2 vasopressin receptor. 1002 23

The expression of the three key peptide processing enzyme families, represented by CPE, PAM, and PC1/3 plus PC2, were examined in MCF-7 and ZR-75-1 breast cancer cell lines. Both of these cell lines express vasopressin receptors as well as the vasopressin gene, but the processing of vasopressin gene-related proteins appears to be limited. Products of the expected size for, CPE, PAM and PC1/PC3 could be amplified by reverse transcription-polymerase chain reaction (RT-PCR) from both cell lines. Cloning and sequencing of these RT-PCR products revealed that each enzyme mRNA had a structure identical to that published for the human form of the respective enzyme. Western analysis provided evidence that mRNAs for these enzymes are translated into proteins. Alternatively, PC2 mRNA was identified to be present in MCF-7 cells both by RT-PCR and Western blot analysis, but could not be demonstrated for ZR-75-1 cells. Our findings suggest that the key processing enzymes needed to generate active vasopressin and other neuropeptide growth factors are present in breast cancer cells.
 ...
PMID:Key peptide processing enzymes are expressed by breast cancer cells. 1127 71

In this study, we establish that the V1a vasopressin receptor (V1aR) is palmitoylated, and we show that this modification has an important functional role. Palmitoylation of the V1aR occurs within the Cys371/Cys372 couplet located in the proximal C-terminal tail domain. Substitution of these residues in a [C371G/C372G]V1aR construct effectively disrupted receptor palmitoylation. Our data also indicate an additional palmitoylation site at another locus in the receptor, as yet undefined. [3H]Palmitate incorporation was agonist-sensitive and increased following exposure to [Arg8]vasopressin (AVP). Given the hydrophobic nature of the acyl chain, palmitoylation of the C terminus of G-protein-coupled receptors has been proposed to form an additional intracellular loop. Consequently, palmitoylation/depalmitoylation will have a profound effect on the local conformation of this domain. The V1aR palmitoylation status regulated both phosphorylation and sequestration of the receptor, and furthermore, palmitoylation, phosphorylation, and sequestration were all regulated by AVP. The palmitoylation-defective construct [C371G/C372G]V1aR exhibited decreased phosphorylation compared to wild-type V1aR, under both basal and AVP-stimulated conditions, and was sequestered at a faster rate. In contrast, the binding of four different classes of ligand and intracellular signaling were not affected by palmitoylation. This study therefore establishes that there are different conformational requirements for signaling, agonist-induced phosphorylation, and sequestration of the V1aR.
 ...
PMID:Palmitoylation of the vasopressin V1a receptor reveals different conformational requirements for signaling, agonist-induced receptor phosphorylation, and sequestration. 1146 23