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

Three main pathways have been implicated in desensitization of receptors that stimulate adenylylcyclase (AC): cAMP-mediated phosphorylation; cAMP-independent phosphorylation, and receptor internalization. Cell lines derived from the murine Ltk- cell were found useful in exploring the contribution of cAMP-dependent phosphorylation in V2 vasopressin receptor desensitization. The HTB-2 cell expresses the human V2 vasopressin receptor, introduced by transfection of human genomic DNA, and the prostaglandin E1 (PGE1) receptor, endogenous to the Ltk- cell. The A7 cell expresses the hamster beta 2-adrenoceptor, which undergoes the above-mentioned desensitization processes. Treatment of HTB-2 cells with arginine-vasopressin (AVP) had no effect on AC responsiveness to PGE1, but promoted desensitization of the AVP response. This was seen as a 5-6-fold right shift in the dose-response curves for AVP action (cAMP accumulation in intact cells and AC stimulation in homogenates and isolated membranes) and in a decrease in the maximum effect of AVP on these parameters. AVP treatment caused a decrease in cell surface receptors to approximately 75% of control without changes in KD, as determined by Scatchard analysis. When cAMP was increased by treatment with 10 microM PGE1 and isobutylmethylxanthine, desensitization of the PGE1 receptor was observed but not of the AVP receptor. In A7 cells the same treatment caused, as expected, a 3-fold right shift in the dose-response curve for AC stimulation by isoproterenol, indicating that L cells can mediate heterologous desensitization. These data demonstrate that the V2 vasopressin and the PGE1 receptors undergo homologous desensitization in the absence of cAMP-mediated phosphorylation and that this component is not required for vasopressin receptor internalization.
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PMID:Desensitization of the human V2 vasopressin receptor. Homologous effects in the absence of heterologous desensitization. 137 12

Human genomic DNA and the HSV tk gene were cotransfected into mouse Ltk- cells and assayed for the acquisition of a Gs-coupled receptor to obtain cell lines expressing human receptors that are so far unavailable. The transfected cells were distributed into 96-well microtitration plates at a density such that after HAT (100 microM hypoxanthine, 1 microM aminopterin, and 10 microM thymidine) selection each well contained, on the average, two to three tk+ cell clones. After replication, half of them were tested for expression of a new phenotype: an adenylyl cyclase stimulatory receptor not normally expressed in the Ltk- recipient cell. The screen yielded a positive result on testing cells arising from the third transfection, the newly expressed receptor is that for arginine vasopressin, commonly referred to as type 2 or V2. DNA from primary transformants (HTB-1 cells) served to obtain secondary transformants by the same technique (HTB-2 cells). Pharmacological properties confirmed that this new receptor, which stimulates adenylyl cyclase activity 7- to 10-fold, is the human V2 receptor and not the activated homologous murine gene. The new cell line provides a permanent accessible source to study the human receptor, by-passing the need for human kidneys. The V2 receptor was susceptible to homologous down-regulation in the HTB-2 cell, but no down-regulation of the cell authentic prostaglandin E1 receptor was observed. The vasopressin receptor did not modify phospholipase-C activity in these cells as expected from V2 receptors. Thus, we successfully applied genomic DNA-mediated gene transfer and were able to develop a cell line expressing a Gs-coupled human receptor of low abundance and poor accessibility.
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PMID:Development and characterization of a mouse cell line expressing the human V2 vasopressin receptor gene. 213 94