From vasopressin receptor to water channel: intracellular traffic, constraint and by-pass

Laycock, John; Hanoune, Jacques

doi:10.1677/joe.0.1590361

Cited by 20 publications

(8 citation statements)

References 71 publications

(59 reference statements)

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“…Although the exact mechanism of agonist-induced desensitization is not yet fully understood, when considering the fact that AQP2 protein did not significantly increase under basal conditions in Tg rats, there may be a contribution from some other mechanism(s), such as a change in the G protein or adenyle-cyclase regulation in the downstream signal transduction system of V2R prior to AQP2 expression (Laycock & Hanoune 1998). Our animal model will be useful to clarify the in vivo adaptive mechanism in the hormone excess state.…”

Section: Discussionmentioning

confidence: 99%

Adaptation to sustained high plasma vasopressin in water and electrolyte homeostasis in the rat transgenic for the metallothionein-vasopressin fusion gene

Yokoi

Nagasaki

Tachikawa

et al. 2002

Journal of Endocrinology

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Prolonged exposure of tissues to a receptor agonist often leads to adaptive changes that limit the subsequent responsiveness of the tissue to the same agonist. Recently, we have generated rats transgenic for the metallothionein I-human arginine vasopressin (AVP) fusion gene (Tg), which produced high plasma AVP with relatively preserved renal water excretion, suggesting that there might be adaptive mechanism(s) for maintaining water and electrolyte homeostasis against chronic AVP oversecretion from the earliest stage of life. In this study, to investigate whether down-regulation of AVP V2 receptor (V2R), which could possibly be caused by long-standing high plasma AVP, participates in this adaptive mechanism(s), non-peptidic V2R antagonist OPC31260 was administered to reverse the down-regulation, and water loading was performed after V2R antagonist treatment had been withdrawn. Additionally, to confirm the down-regulation, Northern blotting analysis for V2R mRNA was carried out. Tg rats showed slightly decreased urine volume and water intake with an equivalent plasma [Na + ] level (Tg 140·4 0·6 mEq/l; control 139·3 0·6 mEq/l) under basal conditions. After water loading using a liquid diet containing zinc, which stimulates the promoter region in the transgene, the urine increase showed only limited suppression with a dramatically increased plasma AVP level and mild hyponatremia (135·8 1·8 mEq/l) in Tg rats. When diet containing OPC31260 had been provided for 4 days until the day before the start of water loading, antidiuresis and hyponatremia (125·4 1·4 mEq/l) were significantly potentiated. V2R mRNA expression in kidney was significantly less in Tg rats than in control rats under basal conditions, and this suppression was restored by OPC31260 treatment to levels comparable with those of control rats. These results suggest that long-standing high plasma AVP causes V2R down-regulation, and it may play an important role in the adaptive mechanism(s) for maintaining water and electrolyte homeostasis in chronically AVP-overexpressing rats.

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Section: Discussionmentioning

confidence: 99%

Adaptation to sustained high plasma vasopressin in water and electrolyte homeostasis in the rat transgenic for the metallothionein-vasopressin fusion gene

Yokoi

Nagasaki

Tachikawa

et al. 2002

Journal of Endocrinology

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“…In kidney epithelia, AQP2 shuttles into and out of apical membranes in response to vasopressin stimulation (reviewed in [3,5,17,29]). In contrast, the distributions of AQP3 and AQP4 are not acutely affected by vasopressin, i.e.…”

Section: Discussionmentioning

confidence: 99%

Evidence that aquaporin-8 is located in the basolateral membrane of rat submandibular gland acinar cells

Wellner

Hoque

Goldsmith

et al. 2000

Pflügers Arch - Eur J Physiol

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It is possible that, during primary saliva formation, aquaporins (AQPs) facilitate transcellular water flow across acinar cells to the lumina of salivary glands. In the rat submandibular gland (rSMG) AQP5 is localized in the apical membranes of acinar cells. The presence of a basolateral AQP in the same cell type has not been reported. We have therefore used immunofluorescence confocal microscopy to determine the subcellular localization of a newly discovered aquaporin, AQP8, in rSMG epithelial cells. The antibodies we used were made against the amino- or carboxyl-terminus (anti-rAQP8NT and anti-rAQP8CT, respectively) of an AQP8 cloned from rat pancreas and liver (rAQP8). Two lines of evidence suggest that both antibodies are suitable for immunolocalization studies. First, results of immunofluorescence confocal microscopy studies show that both antibodies bind to the plasma membranes of 293 cells infected with an adenovirus encoding rAQP8. Second, results of immunoblots of membranes from infected cells suggest that both antibodies bind to glycosylated and non-glycosylated forms of rAQP8. When tested in frozen sections of rSMG, we could not detect the binding of anti-rAQP8NT to any membranes. In contrast, anti-rAQP8CT binds to the basolateral membranes of acinar (but not ductal) epithelia, suggesting that rAQP8 resides in the basolateral membranes of acinar cells. Lack of anti-rAQPNT binding to basolateral membranes suggests that this epitope is not available in the membranes. Our evidence for the basolateral localization of rAQP8 in acinar cells, coupled with previous findings that AQP5 is localized apically in the same cells, raises the possibility that water crosses the acinar epithelium through these channels during primary saliva formation.

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“…3, 6, and 27), a disease in which the kidney is unable to concentrate urine in response to vasopressin (10,14,23,34). In general, AQP2 mutants causing recessive NDI are misfolded, retained in the endoplasmic reticulum (ER), and are unable to interact with wild-type (WT) AQP2 (30,33).…”

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confidence: 99%

Nephrogenic diabetes insipidus in mice caused by deleting COOH-terminal tail of aquaporin-2

Shi¹,

Cao²,

Qu³

et al. 2007

American Journal of Physiology-Renal Physiology

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In mammals, the hormonal regulation of water homeostasis is mediated by the aquaporin-2 water channel (Aqp2) of the collecting duct (CD). Vasopressin induces redistribution of Aqp2 from intracellular vesicles to the apical membrane of CD principal cells, accompanied by increased water permeability. Mutations of AQP2 gene in humans cause both recessive and dominant nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin. In this study, we generated a line of mice with the distal COOH-terminal tail of the Aqp2 deleted (Aqp2(Delta230)), including the protein kinase A phosphorylation site (S256), but still retaining the putative apical localization signal (221-229) at the COOH-terminal. Mice heterozygous for the truncation appear normal. Homozygotes are viable to adulthood, with reduced urine concentrating capacity, increased urine output, decreased urine osmolality, and increased daily water consumption. Desmopressin increased urine osmolality in wild-type mice but had no effect on Aqp2(Delta230/Delta230) mice. Kidneys from affected mice showed CD and pelvis dilatation and papillary atrophy. By immunohistochemical and immunoblot analyses using antibody against the NH(2)-terminal region of the protein Aqp2(Delta230/Delta230) mice had a markedly reduced protein abundance. Expression of the truncated protein in MDCK cells was consistent with a small amount of functional expression but no stimulation. Thus we have generated a mouse model of NDI that may be useful in studying the physiology and potential therapy of this disease.

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From vasopressin receptor to water channel: intracellular traffic, constraint and by-pass

Cited by 20 publications

References 71 publications

Adaptation to sustained high plasma vasopressin in water and electrolyte homeostasis in the rat transgenic for the metallothionein-vasopressin fusion gene

Adaptation to sustained high plasma vasopressin in water and electrolyte homeostasis in the rat transgenic for the metallothionein-vasopressin fusion gene

Evidence that aquaporin-8 is located in the basolateral membrane of rat submandibular gland acinar cells

Nephrogenic diabetes insipidus in mice caused by deleting COOH-terminal tail of aquaporin-2

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