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

It is well established that transient receptor potential (TRP) channels are activated following stimulation of G protein-coupled membrane receptors linked to PLC, but their differential expression in various cells of the renal nephron has not been described. In the present study, immunoprecipitations from rat kidney lysates followed by Western blot analysis using TRPC-specific, affinity-purified antibodies revealed the presence of TRPC1, -C3, and -C6. TRPC4, -C5, and -C7 were nondetectable. TRPC1 immunofluorescence was detected in glomeruli and specific tubular cells of the cortex and outer medulla. TRPC1 colocalized with aquaporin-1, a marker for proximal tubule and thin descending limb, but not with aquaporin-2, a marker for connecting tubule and collecting duct cells. TRPC3 and -C6 immunolabeling was predominantly confined to glomeruli and specific tubular cells of the cortex and both the outer and inner medulla. TRPC3 and -C6 colocalized with aquaporin-2, but not with the Na(+)/Ca(2+) exchanger or peanut lectin. Thus TRPC3 and -C6 proteins are expressed in principle cells of the collecting duct. In polarized cultures of M1 and IMCD-3 collecting duct cells, TRPC3 was localized exclusively to the apical domain, whereas TRPC6 was found in both the basolateral and apical membranes. TRPC3 and TRPC6 were also detected in primary podocyte cultures, whereas TRPC1 was exclusively expressed in mesangial cell cultures. Specific immunopositive labeling for TRPC4, -C5, or -C7 was not observed in kidney sections or cell lines. These results suggest that TRPC1, -C3, and -C6 may play a functional role in PLC-dependent signaling in specific regions of the nephron.
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PMID:Identification and localization of TRPC channels in the rat kidney. 1630 55

The canonical transient receptor potential channels TRPC3 and TRPC6 are abundantly expressed along with the water channel aquaporin-2 (AQP2) in principal cells of the cortical and medullary collecting duct. Although TRPC3 is selectively localized to the apical membrane and TRPC6 is found in both the apical and basolateral domains, immunofluorescence is often observed in the cytoplasm, suggesting that TRPC3 and TRPC6 may exist in intracellular vesicles and may shuttle to and from the membrane in response to receptor stimulation. To test this hypothesis, the effect of arginine-vasopressin (AVP) on the subcellular distribution of TRPC3, TRPC6, and AQP2 was examined in the rat kidney and in cultured cell lines from the cortical (M1) and inner medullary (IMCD-3) collecting duct. Immunofluorescence analysis revealed that TRPC3, but not TRPC6, colocalized with AQP2 in intracellular vesicles. AVP caused the insertion and accumulation of TRPC3 and AQP2 in the apical membrane but had no effect on the subcellular distribution of TRPC6. TRPC3, but not TRPC6, coimmunoprecipitated with AQP2 from both medulla and M1 and IMCD-3 cell lysates. Apical-to-basolateral transepithelial 45Ca2+ flux in polarized IMCD-3 cell monolayers was stimulated by diacylglycerol analogs or by the purinergic receptor agonist ATP but not by thapsigargin. Stimulated 45Ca2+ flux was increased by overexpression of TRPC3 and attenuated by a dominant-negative TRPC3 construct. Furthermore, 45Ca2+ flux was greatly reduced by the pyrazole-derivative BTP2, a known inhibitor of TRPC3 channels. These results demonstrate that 1) TRPC3 and TRPC6 exist in different vesicle populations, 2) TRPC3 physically associates with APQ2 and shuttles to the apical membrane in response to AVP, and 3) TRPC3 is responsible for transepithelial Ca2+ flux in principal cells of the renal collecting duct.
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PMID:Vasopressin-induced membrane trafficking of TRPC3 and AQP2 channels in cells of the rat renal collecting duct. 1769 54

The transient receptor potential (TRP) superfamily consists, in mammals, of six protein subfamilies, TRPC, TRPM, TRPV, TRPA, TRPML and TRPP. TRPs are cation channels involved in many physiological processes and in the pathogenesis of various disorders. In the kidney, TRP channels are expressed along the nephron, and a role for some of these channels in renal function has been proposed. TRPC3 is thought to facilitate calcium ion influx into the principal cells of the collecting duct in response to vasopressin. TRPM3 and TRPV4 might be osmosensors, whereas the TRPP1/TRPP2 complex could function as a mechanosensor in the cilia of renal epithelial cells. A number of kidney diseases have also been linked to dysfunctional activity of TRPs. TRPC6 dysfunction has been associated with the onset of focal segmental glomerosclerosis; TRPP2 dysfunction is linked to autosomal-dominant polycystic kidney disease, TRPM6 mutations underlie hypomagnesemia with secondary hypocalcemia, and TRPV1 dysfunction is implicated in renal hypertension. A link between TRPC1 dysfunction and diabetic nephropathy has also been suggested in an animal model. Animal studies have implicated a role for TRPV5 in idiopathic hypercalciuria and vitamin D-dependent rickets, although these observations have not been confirmed in patients. This Review focuses on the role of renal TRP channels in health and disease.
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PMID:The role of transient receptor potential channels in kidney disease. 1954 62

Transient receptor potential channels TRPC3 and TRPC6 are expressed in principal cells of the collecting duct (CD) along with the water channel aquaporin-2 (AQP2) both in vivo and in the cultured mouse CD cell line IMCD-3. The channels are primarily localized to intracellular vesicles, but upon stimulation with the antidiuretic hormone arginine vasopressin (AVP), TRPC3 and AQP2 translocate to the apical membrane. In the present study, the effect of various activators and inhibitors of the adenylyl cyclase (AC)/cAMP/PKA signaling cascade on channel trafficking was examined using immunohistochemical techniques and by biotinylation of surface membrane proteins. Both in vivo in rat kidney and in IMCD-3 cells, translocation of AQP2 and TRPC3 (but not TRPC6) was stimulated by [deamino-Cys(1), d-Arg(8)]-vasopressin (dDAVP), a specific V2-receptor agonist, and blocked by [adamantaneacetyl(1), O-Et-d-Tyr(2), Val(4), aminobutyryl(6), Arg(8,9)]-vasopressin (AEAVP), a specific V2-receptor antagonist. In IMCD-3 cells, translocation of TRPC3 and AQP2 was activated by forskolin, a direct activator of AC, or by dibutyryl-cAMP, a membrane-permeable cAMP analog. AVP-, dDAVP-, and forskolin-induced translocation in IMCD-3 cells was blocked by SQ22536 and H89, specific inhibitors of AC and PKA, respectively. Translocation stimulated by dibutyryl-cAMP was unaffected by AEAVP but could be blocked by H89. AVP- and forskolin-induced translocation of TRPC3 in IMCD-3 cells was also blocked by two additional inhibitors of PKA, specifically Rp-cAMPS and the myristoylated inhibitor of PKA (m-PKI). Quantification of TRPC3 membrane insertion in IMCD-3 cells under each assay condition using a surface membrane biotinylation assay, confirmed the translocation results observed by immunofluorescence. Importantly, AVP-induced translocation of TRPC3 as estimated by biotinylation was blocked on average 95.2 +/- 1.0% by H89, Rp-cAMPS, or m-PKI. Taken together, these results demonstrate that AVP stimulation of V2 receptors in principal cells of the CD causes translocation of TRPC3 to the apical membrane via stimulation of the AC/cAMP/PKA signaling cascade.
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PMID:Role of cAMP/PKA signaling cascade in vasopressin-induced trafficking of TRPC3 channels in principal cells of the collecting duct. 2010 12

The transient receptor potential channel TRPC3 is exclusively expressed in the apical membrane of principal cells of the collecting duct (CD) both in vivo and in the mouse CD cell line IMCD-3. Previous studies revealed that ATP-induced apical-to-basolateral transepithelial Ca(2+) flux across IMCD-3 monolayers is increased by overexpression of TRPC3 and attenuated by a dominant negative TRPC3 construct, suggesting that Ca(2+) entry across the apical membrane occurs via TRPC3 channels. To test this hypothesis, we selectively measured the Ca(2+) permeability of the apical membrane of fura-2-loaded IMCD-3 cells using the Mn(2+) quench technique. Mn(2+) influx across the apical membrane was increased 12- to 16-fold by apical ATP and was blocked by the pyrazole derivative BTP2, a known inhibitor of TRPC3 channels, with an IC(50) value <100 nM. In contrast, Mn(2+) influx was only increased approximately 2-fold by basolateral ATP. Mn(2+) influx was also activated by apical, but not basolateral, 1-stearoyl-2-acetyl-sn-glycerol (SAG), a known activator of TRPC3 channels. Apical ATP- and SAG-induced Mn(2+) influx was increased by overexpression of TRPC3 and completely blocked by expression of the dominant negative TRPC3 construct. Mn(2+) influx was also stimulated approximately 2-fold by thapsigargin applied to either the apical or basolateral side. Thapsigargin-induced flux was blocked by BTP2 but was unaffected by overexpression of TRPC3 or by dominant negative TRPC3. Apical ATP, but not basolateral ATP, increased transepithelial (45)Ca(2+) flux. These results demonstrate that the apical membrane of IMCD-3 cells has two distinct Ca(2+) influx pathways: 1) a store-operated channel activated by thapsigargin and basolateral ATP and 2) TRPC3 channels activated by apical ATP. Only activation of TRPC3 leads to net transepithelial apical-to-basolateral Ca(2+) flux. Furthermore, these results demonstrate that native TRPC3 is not a store-operated channel in IMCD-3 cells.
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PMID:Role of TRPC3 channels in ATP-induced Ca2+ signaling in principal cells of the inner medullary collecting duct. 2041 Feb 14

It is well-established that the kidney collecting duct (CD) plays a central role in regulation of systemic water homeostasis. Aquaporin 2 (AQP2)-dependent water reabsorption in the CD critically depends on the arginine vasopressin (AVP) antidiuretic input and the presence of a favorable osmotic gradient at the apical plasma membrane with tubular lumen being hypotonic compared to the cytosol. This osmotic difference creates a mechanical force leading to an increase in [Ca2+]i in CD cells. The significance of the osmosensitive [Ca2+]i signaling for renal water transport and urinary concentration remain unknown. To examine molecular mechanism and physiological relevance of osmosensitivity in the CD, we implemented simultaneous direct measurements of [Ca2+]i dynamics and the rate of cell swelling as a readout of the AQP2-dependent water reabsorption in freshly isolated split-opened CDs of wild type and genetically manipulated animals and combined this with immunofluorescent detection of AVP-induced AQP2 trafficking and assessment of systemic water balance. We identified the critical role of the Ca2+-permeable TRPC3 channel in osmosensitivity and water permeability in the CD. We further demonstrated that TRPC3 -/- mice exhibit impaired urinary concentration, larger urinary volume and a greater weight loss in response to water deprivation despite increased AVP levels and AQP2 abundance. TRPC3 deletion interfered with AQP2 translocation to the plasma membrane in response to water deprivation. In summary, we provide compelling multicomponent evidence in support of a critical contribution of TRPC3 in the CD for osmosensitivity and renal water handling.
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PMID:TRPC3 determines osmosensitive [Ca2+]i signaling in the collecting duct and contributes to urinary concentration. 3185 15