Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P41181 (collecting duct)
5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We examined the sites of peptide hormone activation within medullary nephron segments of the house sparrow (Passer domesticus) kidney by measuring rates of hormone-induced generation of cyclic nucleotide second messenger. Thin descending limbs, thick ascending limbs, and collecting ducts had baseline activity of adenylyl cyclase that resulted in cAMP accumulation of 207 +/- 56, 147 +/- 31, and 151 +/- 41 fmol. mm-1. 30 min-1, respectively. In all segments, this activity increased 10- to 20-fold in response to forskolin. Activity of adenylyl cyclase in the thin descending limb was stimulated approximately twofold by parathyroid hormone (PTH) but not by any of the other hormones tested [arginine vasotocin (AVT), glucagon, atrial natriuretic peptide (ANP), or isoproterenol, each at 10(-6) M]. Thick ascending limb was stimulated two- to threefold by both AVT and PTH; however, glucagon and isoproterenol had no effect, and ANP stimulated neither cAMP nor cGMP accumulation. Adenylyl cyclase activity in the collecting duct was stimulated fourfold by AVT but not by the other hormones; likewise, ANP did not stimulate cGMP accumulation in this segment. These data support a tubular action of AVT and PTH in the avian renal medulla.
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PMID:Second messenger production in avian medullary nephron segments in response to peptide hormones. 1007 Jan 47

Adenylyl cyclase (AC) type VI (AC6) is a calcium-inhibitable enzyme which produces cAMP upon stimulation. Herein, we characterized the specific role of AC6 in the kidneys using two AC6-knockout mouse lines. Immunohistochemical staining revealed that AC6 exists in the tubular parts of the nephron and collecting duct. Activities of AC evoked by forskolin or a selective agonist of the V2 vasopressin receptor were lower in the kidneys of AC6-null mice compared to those of wildtype mice. Results of a metabolic cage assay and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) showed for the first time that AC6 plays a critical role in regulating water homeostasis.
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PMID:Impaired water reabsorption in mice deficient in the type VI adenylyl cyclase (AC6). 2046 3

The primary cilium is an organelle that serves as a signaling center of the cell and is involved in the cAMP, Wnt, and hedgehog signaling pathways. Adenylyl cyclase type III (ACIII) is enriched in primary cilia and acts as a marker that is involved in cAMP signaling, while also playing an important role in regulating ciliogenesis and sensory functions. Ciliary function relies on the transportation of molecules between the primary cilium and the cell, which is facilitated by intraflagellar transport (IFT). The detailed localization and interactions of these important proteins remain unclear due to the limited resolution of conventional microscopy. We conducted superresolution imaging of immunostained ACIII and IFT88 in human fibroblasts using stimulated emission depletion (STED) microscopy. Instead of a homogeneous distribution along a primary cilium, our STED images revealed that ACIII formed a periodic punctate pattern with a roughly equal spacing between groups of puncta. Superresolution imaging of IFT88, an important protein of the IFT complexes, demonstrated two novel distinct distribution patterns at the basal end: a triangle of three puncta with similar fluorescence intensities, and a Y-shaped configuration of a bright punctum connected to two branches. We also performed STED imaging of IFT88 in mouse inner medullary collecting duct cells and mouse embryonic fibroblasts. The similar three-puncta and Y-shape patterns were observed in these cells, suggesting that these distribution patterns are common among primary cilia of different cell types. Our results demonstrate the ability of superresolution STED microscopy to reveal novel structural characteristics in primary cilia.
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PMID:Superresolution STED microscopy reveals differential localization in primary cilia. 2312 24

Abstract Adenylyl cyclase (AC)-stimulated cAMP is a key mediator of collecting duct (CD) Na and water transport. AC isoforms 3, 4, and 6 are expressed in the CD. Our group demonstrated that AC6, but not AC3, is involved in regulating CD Na and water transport. However, the role of AC4 in such regulation remains unknown. Therefore, we generated mice with loxP-flanked critical exons in the Adcy4 gene and bred with mice expressing the aquaporin-2/Cre recombinase transgene to yield CD principal cell-specific knockout of AC4 (CD AC4 KO). Isolated inner medullary CD showed 100% genomic target gene recombination in CD AC4 KO mice, while microdissected cortical CD and renal papillary AC4 mRNA was significantly reduced in CD AC4 KO mice. CD AC4 KO had no effect on vasopressin (AVP)-stimulated cAMP generation in the inner medulla. Water intake, urine volume, and urine osmolality were similar between CD AC4 KO and control mice during normal or restricted water intake. Sodium intake, urinary Na excretion, and blood pressure on a normal-, high-, or low-Na diet were not affected by CD AC4 KO. Moreover, there were no differences in plasma AVP or plasma renin concentration between CD AC4 KO and control mice. In summary, these data suggest that CD AC4 does not play a role in the physiologic regulation of CD Na and water handling.
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PMID:Adenylyl cyclase 4 does not regulate collecting duct water and sodium handling. 2476 May 29

Adenylyl cyclase (AC) isoform 6 (AC6) is highly expressed throughout the renal tubule and collecting duct (CD), catalyzes the synthesis of cAMP and contributes to various aspects of renal transport. Several proteins involved in acid-base homeostasis are regulated by cAMP. In the present study, we assess the relative contribution of AC6 to overall acid-base regulation using mice with global deletion of AC6 (AC6-/-) or newly generated mice lacking AC6 in the renal tubule and CD (AC6loxloxPax8Cre). Higher energy expenditure in AC6-/- relative to wild-type (WT) mice, was associated with lower urinary pH, mild alkalosis in conjunction with elevated blood HCO3- concentrations, and significantly higher renal abundance of the H+-ATPase B1 subunit. In contrast with WT mice, AC6-/- mice have a less pronounced increase in urinary pH after 8 days of HCO3- challenge, which is associated with increased blood pH and HCO3- concentrations. Immunohistochemistry demonstrated that AC6 was expressed in intercalated cells (IC), but subcellular distribution of the H+-ATPase B1 subunit, pendrin, and the anion exchangers 1 and 2 in AC6-/- mice was normal. In the AC6-/- mice, H+-ATPase B1 subunit levels after HCO3- challenge were greater, which correlated with a higher number of type A IC. In contrast with the AC6-/- mice, AC6loxloxPax8Cre mice had normal urinary pH under baseline conditions but higher blood HCO3- than controls after HCO3- challenge. In conclusion, AC6 is required for maintaining normal acid-base homeostasis and energy expenditure. Under baseline conditions, renal AC6 is redundant for acid-base balance but becomes important under alkaline conditions.
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PMID:Adenylyl cyclase 6 is required for maintaining acid-base homeostasis. 3022 Jun 52