Immunolocalization and effect of dehydration on AQP3, a basolateral water channel of kidney collecting ducts

1997 ◽  
Vol 272 (2) ◽  
pp. F235-F241 ◽  
Author(s):  
K. Ishibashi ◽  
S. Sasaki ◽  
K. Fushimi ◽  
T. Yamamoto ◽  
M. Kuwahara ◽  
...  
Keyword(s):  
Xenopus Oocytes ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Broad Band ◽  
Water Channel ◽  
In Vitro Translation ◽  
Mercury Chloride ◽  
Channel Activity ◽  
Kidney Medulla ◽  
Principal Cells

Aquaporin-3 (AQP3) is unique in its structure (lowest homology with other aquaporins) and in its function (significantly conductive to both small nonelectrolytes and water). However, there is a controversy among researchers on its water transport and induction by dehydration. We examined its localization and the effect of dehydration on its expression in the kidney, as well as its water channel activity when expressed in Xenopus oocytes. In vitro translation using reticulocyte lysate revealed that the size of rat AQP3 was 26 kDa, and the band shifted to around 31 kDa with microsomal fraction, which was sensitive to the digestion with N-glycosidase F. In Western blot analysis of rat kidney medulla, AQP3 appeared as a sharp band at 27 kDa and a broad band at 34-40 kDa. In immunohistochemistry, AQP3 was localized to principal cells and absent in intercalated cells in outer medulla. In inner medulla, AQP3 was restricted to inner medullary collecting duct (IMCD) cells. AQP3 was confined to the basolateral membrane of these cells. Although dehydration of rats for 2 days did not change the distribution pattern of AQP3 in IMCD cells, the dehydration increased AQP3 mRNA by twofold with slight increase of its protein level in kidney medulla. Finally, we confirmed its water channel activity when expressed in Xenopus oocytes. The human AQP3 stimulated osmotic water permeability by eightfold, which was inhibited by 0.3 mM mercury chloride by 34% and reversed by beta-mercaptoethanol. Our results indicate that AQP3 is a glycosylated protein and a mercury-sensitive water channel localized at the basolateral membrane of principal cells and IMCD cells, and its expression is induced by dehydration at both protein and mRNA level.

Functional characterization and cell immunolocalization of AQP-CD water channel in kidney collecting duct

1994 ◽  
Vol 267 (4) ◽  
pp. F573-F582 ◽  
Author(s):  
K. Fushimi ◽  
S. Sasaki ◽  
T. Yamamoto ◽  
M. Hayashi ◽  
T. Furukawa ◽  
...  
Keyword(s):  
Water Permeability ◽  
Expression Vector ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Functional Characterization ◽  
Protein A ◽  
Water Channel ◽  
Kidney Medulla ◽  
Principal Cells ◽  
Kidney Collecting Duct

Vasopressin-regulated water permeability of the kidney collecting duct is a key component of the urine concentration machinery. Recently, a cDNA for AQP-CD, the vasopressin-regulated water channel, initially reported as WCH-CD, has been isolated (K. Fushimi, S. Uchida, Y. Hara, Y. Hirata, F. Marumo, and S. Sasaki. Nature Lond. 361: 549-552, 1993). AQP-CD was expressed in oocyte membrane using a Xenopus expression vector, and functional characteristics of AQP-CD were examined. Osmotic water permeability (Pf) of oocytes expressing AQP-CD was 138 +/- 19 microns/s (mean +/- SE), 12 times greater than the control (11 +/- 3 microns/s), 90% inhibited by 0.3 mM HgCl2, and weakly temperature dependent (energy of activation for Pf was 4.0 kcal/mol). Urea influx measured from 15-min [14C]urea uptake by oocytes injected with AQP-CD/expression vector 1 cRNA was 86 +/- 17% of the control. Two-electrode voltage-clamp experiments revealed insignificant ion conductance of AQP-CD. Immunoblots of membranes from rat kidney medulla and oocytes expressing AQP-CD using anti-AQP-CD COOH-terminal antibody showed a 29-kDa protein and 35- to 50-kDa high-molecular-mass forms. Immunohistochemistry showed apical and subapical localization of AQP-CD in the collecting duct principal cells. Our results indicated that AQP-CD is a 29-kDa protein, a selective water channel, distinct from a urea channel, and localized to the membranes of vasopressin-sensitive components in kidney collecting duct principal cells.

Localization of MIWC and GLIP water channel homologs in neuromuscular, epithelial and glandular tissues

1995 ◽  
Vol 108 (9) ◽  
pp. 2993-3002 ◽  
Author(s):  
A. Frigeri ◽  
M.A. Gropper ◽  
F. Umenishi ◽  
M. Kawashima ◽  
D. Brown ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Urinary Bladder ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Water Channel ◽  
Parietal Cells ◽  
Immunogold Electron Microscopy ◽  
Transitional Epithelium ◽  
Principal Cells ◽  
Kidney Collecting Duct

It was shown recently that water channel homologs MIWC (mercurial insensitive water channel) and GLIP (glycerol intrinsic protein) colocalized in basolateral membranes of kidney collecting duct, tracheal and colonic epithelia, and in brain pia mater. We report here an extensive immunolocalization study of MIWC and GLIP in non-epithelial and glandular epithelial tissues in rat. Immunogold electron microscopy confirmed colocalization of MIWC and GLIP in basolateral membrane of principal cells in kidney collecting duct. However, in other epithelia, MIWC but not GLIP was expressed in basolateral membrane of parietal cells in stomach, and in excretory tubules of salivary and lacrimal glands; GLIP but not MIWC was expressed in transitional epithelium of urinary bladder and skin epidermis. In the central nervous system, MIWC was strongly expressed in the ependymal layer lining the aqueductal system, and in astrocytes throughout the spinal cord and in selected regions of brain. MIWC was also expressed in a plasma membrane pattern in skeletal, but not smooth or cardiac muscle. Neither protein was expressed in small intestine, testis, liver, spleen and nerve. The tissue-specific expression of MIWC suggests a role in fluid transport and/or cell volume regulation in stomach and glandular epithelia. The functional role of MIWC expression in the neuromuscular system and of GLIP expression in skin and urinary bladder is uncertain. The specific cellular sites of MIWC expression (astrocytes, trachea, sarcolemma, gastric parietal cells and kidney principal cells) correspond exactly to sites where orthogonal arrays of particles (OAPs) have been visualized by freeze-fracture electron microscopy, suggesting that MIWC may be the OAP protein.

Membrane topology and immunolocalization of CHIF in kidney and intestine

2001 ◽  
Vol 280 (3) ◽  
pp. F505-F512 ◽  
Author(s):  
Haikun Shi ◽  
Rivi Levy-Holzman ◽  
Francoise Cluzeaud ◽  
Nicolette Farman ◽  
Haim Garty
Keyword(s):  
Collecting Duct ◽  
Basolateral Membrane ◽  
Distal Colon ◽  
Membrane Topology ◽  
In Vitro Translation ◽  
Cell Interior ◽  
Kidney Medulla ◽  
Protease Digestion ◽  
Corticosteroid Hormone

Corticosteroid hormone-induced factor (CHIF) is an aldosterone-induced gene, the function of which is yet unknown. It is specifically expressed in kidney collecting duct (CD) and distal colon and is upregulated by either Na+ deprivation or K+ loading. Hence, it may play a role in epithelial electrolyte transport. Previous studies have characterized regulation and tissue distribution of CHIF mRNA but provided no information on the protein itself. The present paper addresses this issue by using Western blotting, immunochemistry, and in vitro translation. CHIF is an ∼8-kDa membranal protein, and protease digestion experiments suggest that its COOH tail faces the cell interior. The protein is abundant in distal colon, kidney medulla, and papilla but cannot be detected in a variety of other tissues. Confocal immunocytochemistry demonstrates that CHIF is present in the basolateral membrane of CD principal cells and distal colon surface cells, with occasional intracellular staining. Dexamethasone and low Na+ intake increase the abundance of CHIF. Unlike previous Northern data, induction of CHIF protein by low-Na+ intake was apparent not only in the distal colon but also in the kidney.

scholarly journals Basolateral targeting and microtubule-dependent transcytosis of the aquaporin-2 water channel

2013 ◽  
Vol 304 (1) ◽  
pp. C38-C48 ◽  
Author(s):  
Naofumi Yui ◽  
Hua A. J. Lu ◽  
Ying Chen ◽  
Naohiro Nomura ◽  
Richard Bouley ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cold Shock ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Water Channel ◽  
Apical Plasma Membrane ◽  
Indirect Pathway ◽  
Basolateral Membranes ◽  
Principal Cells ◽  
Aquaporin 2

The aquaporin-2 (AQP2) water channel relocates mainly to the apical plasma membrane of collecting duct principal cells after vasopressin (VP) stimulation. AQP2 transport to this membrane domain is assumed to be a direct route involving recycling of intracellular vesicles. However, basolateral plasma membrane expression of AQP2 is observed in vivo in principal cells. Here, we asked whether there is a transcytotic pathway of AQP2 trafficking between apical and basolateral membranes. We used MDCK cells in which AQP2 normally accumulates apically after VP exposure. In contrast, both site-specific biotinylation and immunofluorescence showed that AQP2 is strongly accumulated in the basolateral membrane, along with the endocytic protein clathrin, after a brief cold shock (4°C). This suggests that AQP2 may be constitutively targeted to basolateral membranes and then retrieved by clathrin-mediated endocytosis at physiological temperatures. Rab11 does not accumulate in basolateral membranes after cold shock, suggesting that the AQP2 in this location is not associated with Rab11-positive vesicles. After rewarming (37°C), basolateral AQP2 staining is diminished and it subsequently accumulates at the apical membrane in the presence of VP/forskolin, suggesting that transcytosis can be followed by apical insertion of AQP2. This process is inhibited by treatment with colchicine. Our data suggest that the cold shock procedure reveals the presence of microtubule-dependent AQP2 transcytosis, which represents an indirect pathway of apical AQP2 delivery in these cells. Furthermore, our data indicate that protein polarity data obtained from biotinylation assays, which require cells to be cooled to 4°C during the labeling procedure, should be interpreted with caution.

A basolateral CHIP28/MIP26-related protein (BLIP) in kidney principal cells and gastric parietal cells

1994 ◽  
Vol 267 (3) ◽  
pp. C812-C820 ◽  
Author(s):  
G. Valenti ◽  
J. M. Verbavatz ◽  
I. Sabolic ◽  
D. A. Ausiello ◽  
A. S. Verkman ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Basolateral Membrane ◽  
Water Channel ◽  
Protein S ◽  
High Water ◽  
Protein Band ◽  
Parietal Cells ◽  
Toad Urinary Bladder ◽  
Principal Cells ◽  
Gastric Parietal Cells

The water channel CHIP28 accounts for the high water permeability of proximal tubules and thin descending limbs of Henle; a homologous water channel, WCH-CD, in the apical membrane of collecting duct principal cells, may be the vasopressin-sensitive water channel. We show here that one antiserum, raised against CHIP28, immunostains the basolateral membrane of collecting duct principal cells, in addition to staining CHIP28 in other cells. This serum was named anti-basolateral integral protein (anti-BLIP) to distinguish it from other anti-CHIP28 antisera. By Western blotting, BLIP serum recognized both CHIP28 and MIP26, and it stained lens fibers, which contain MIP26 but not CHIP28. BLIP antiserum immunoprecipitated a 28-kDa band, a broad 35- to 50-kDa band, and an approximately 16-kDa band from kidney papilla. It also stained the basolateral membrane of gastric parietal cells, which were not stained with anti-CHIP28 or anti-MIP26 antibodies. BLIP antiserum immunoprecipitated a 28-kDa protein band from stomach; this protein was not precipitated by anti-CHIP28 antibodies. These results suggest that basolateral membranes of principal cells and parietal cells contain a protein(s) that shares common epitopes with CHIP28 and MIP26. Finally, BLIP but not CHIP28 antiserum stained mesothelial (but not epithelial) cells of toad urinary bladder, a further indication that the BLIP antiserum recognizes a protein distinct from CHIP28.

scholarly journals In Vivo Functional Assay of a Recombinant Aquaporin in Pichia pastoris

2006 ◽  
Vol 72 (2) ◽  
pp. 1507-1514 ◽  
Author(s):  
Mark J. Daniels ◽  
Malcolm R. Wood ◽  
Mark Yeager
Keyword(s):  
Pichia Pastoris ◽  
Linear Relationship ◽  
Osmotic Shock ◽  
Water Channel ◽  
Yeast Cells ◽  
Mercury Chloride ◽  
Functional Assay ◽  
Channel Activity ◽  
Wild Type

ABSTRACT The water channel protein PvTIP3;1 (α-TIP) is a member of the major intrinsic protein (MIP) membrane channel family. We overexpressed this eukaryotic aquaporin in the methylotrophic yeast Pichia pastoris, and immunogold labeling of cellular cryosections showed that the protein accumulated in the plasma membrane, as well as vacuolar and other intracellular membranes. We then developed an in vivo functional assay for water channel activity that measures the change in optical absorbance of spheroplasts following an osmotic shock. Spheroplasts of wild-type P. pastoris displayed a linear relationship between absorbance and osmotic shock level. However, spheroplasts of P. pastoris expressing PvTIP3;1 showed a break in this linear relationship corresponding to hypo-osmotically induced lysis. It is the difference between control and transformed spheroplasts under conditions of hypo-osmotic shock that forms the basis of our aquaporin activity assay. The aquaporin inhibitor mercury chloride blocked water channel activity but had no effect on wild-type yeast. Osmotically shocked yeast cells were affected only slightly by expression of the Escherichia coli glycerol channel GlpF, which belongs to the MIP family but is a weak water channel. The important role that aquaporins play in human physiology has led to a growing interest in their potential as drug targets for treatment of hypertension and congestive heart failure, as well as other fluid overload states. The simplicity of this assay that is specific for water channel activity should enable rapid screening for compounds that modulate water channel activity.

Expression, functional analysis, and in situ hybridization of a cloned rat kidney collecting duct water channel

1994 ◽  
Vol 266 (1) ◽  
pp. C189-C197 ◽  
Author(s):  
T. Ma ◽  
H. Hasegawa ◽  
W. R. Skach ◽  
A. Frigeri ◽  
A. S. Verkman
Keyword(s):  
Base Pair ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Water Channel ◽  
Cloning And Expression ◽  
Base Pairs ◽  
Kidney Medulla ◽  
Coding Sequence ◽  
Kidney Collecting Duct ◽  
Protein Size

The cloning and expression of an apical membrane water channel from rat kidney collecting duct (WCH-CD) homologous to a 28-kDa integral membrane protein (CHIP28) was reported recently (K. Fushimi, S. Uchida, Y. Hara, Y. Hirata, F. Marumo, and S. Sasaki. Nature Lond. 361: 549-552, 1993). We obtained an approximately 1.8-kilobase clone from a rat kidney lambda gt10 cDNA library by a polymerase chain reaction cloning method; whereas the coding sequence (814 base pairs, predicted protein size 29 kDa) was identical to that reported, we identified an in-frame ATG codon at base pair -123 predicting a protein size of 33 kDa. On Northern blots probed by cDNAs corresponding to the WCH-CD coding sequence (base pairs +1 to +814) or 5'-untranslated sequence (-403 to -16), a single band at 1.9 kilobases was observed in kidney medulla greater than in cortex but not in other tissues; mRNA expression was increased strongly by dehydration. Translation and oocyte expression studies were performed to identify the translation start site. The short (base pairs +1 to +814) and long (base pairs -123 to +814) cDNAs were subcloned in vector pSP64 containing the 5'-untranslated Xenopus globin sequence upstream to the ATGs; a 30-base pair c-myc sequence was engineered at the COOH- terminal for antibody recognition.(ABSTRACT TRUNCATED AT 250 WORDS)

Depletion of intercalated cells from collecting ducts of carbonic anhydrase II-deficient (CAR2 null) mice

1995 ◽  
Vol 269 (6) ◽  
pp. F761-F774 ◽  
Author(s):  
S. Breton ◽  
S. L. Alper ◽  
S. L. Gluck ◽  
W. S. Sly ◽  
J. E. Barker ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Collecting Duct ◽  
Water Channel ◽  
Immunofluorescent Staining ◽  
Specific Marker ◽  
Intercalated Cells ◽  
Cortical Collecting Duct ◽  
Principal Cells ◽  
Collecting Tubules ◽  
Deficient Mice

The kidneys of mice (CAR2-null mice) that are genetically devoid of carbonic anhydrase type II (CAII) were screened by immunocytochemistry with antibodies that distinguish intercalated and principal cells. Immunofluorescent localization of the anion exchanger AE1 and of the 56-kDa subunit of the vacuolar H(+)-adenosinetriphosphatase (H(+)-ATPase) was used to identify intercalated cells, while the AQP2 water channel was used as a specific marker for principal cells of the collecting duct. The CAII deficiency of the CAR2-null mice was first confirmed by the absence of immunofluorescent staining of kidney sections exposed to an anti-CAII antibody. Cells positive for AE1 and H(+)-ATPase were common in all collecting duct regions in normal mice but were virtually absent from the inner stripe of the outer medulla and the inner medulla of CAR2-null mice. The number of positive cells was also reduced threefold in the cortical collecting duct of CAR2-null animals compared with normal mice. In parallel, the percentage of AQP2-positive cells was correspondingly increased in the collecting tubules of CAII-deficient mice, whereas the total number of cells per tubule remained unchanged. These results suggest that intercalated cells are severely depleted and are replaced by principal cells in CAII-deficient mice. Quantitative analysis and double staining showed that, in the cortex, both type A and type B intercalated cells are equally affected. Elucidation of the mechanism(s) responsible for this phenotype will be of importance in understanding the origin and development of intercalated cells in the kidney.

Immunocytochemical localization of Na+ channels in rat kidney medulla

1989 ◽  
Vol 256 (2) ◽  
pp. F366-F369 ◽  
Author(s):  
D. Brown ◽  
E. J. Sorscher ◽  
D. A. Ausiello ◽  
D. J. Benos
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Collecting Duct ◽  
Rat Kidney ◽  
Apical Plasma Membrane ◽  
Na Channel ◽  
Thick Ascending Limb ◽  
Na Channels ◽  
Kidney Medulla ◽  
Principal Cells

Amiloride-sensitive Na+ channels were localized in semithin frozen sections of rat renal medullary collecting ducts, using polyclonal antibodies directed against purified bovine kidney Na+ channel protein. The apical plasma membrane of collecting duct principal cells was heavily stained by indirect immunofluorescence, whereas intercalated cells were negative. Basolateral plasma membranes of both cell types were unstained, as were subapical vesicles in the cytoplasm of these cells. In the thick ascending limb of Henle, some scattered granular fluorescence was seen in the cytoplasm and close to the apical pole of epithelial cells, suggesting the presence of antigenic sites associated with some membrane domains in these cells. No staining was detected in thin limbs of Henle, or in proximal tubules in the outer medulla. These results show that amiloride-sensitive sodium channels are located predominantly on the apical plasma membrane of medullary collecting duct principal cells, the cells that are involved in Na+ homeostasis in this region of the kidney.

Structural-functional relationships along the distal nephron

1986 ◽  
Vol 250 (1) ◽  
pp. F1-F15 ◽  
Author(s):  
K. M. Madsen ◽  
C. C. Tisher
Keyword(s):  
Atpase Activity ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Distal Tubule ◽  
Structural Heterogeneity ◽  
Apical Plasma Membrane ◽  
Thick Ascending Limb ◽  
Intercalated Cells ◽  
Principal Cells ◽  
Functional Relationships

The distal tubule, which includes the thick ascending limb (TAL), the macula densa, and the distal convoluted tubule (DCT), and the collecting duct are structurally heterogeneous, thus reflecting the functional heterogeneity that is also present. As the TAL ascends from medulla to cortex, the surface area of the apical plasma membrane increases while that of the basolateral membrane decreases. The structure of the DCT resembles that of the medullary TAL. An excellent correlation exists between structure, Na-K-ATPase activity, and NaCl reabsorptive capacity in the distal tubule. The collecting duct is subdivided into the initial collecting tubule (ICT), and cortical (CCD), outer medullary (OMCD), and inner medullary (IMCD) collecting ducts. Between the distal tubule and the collecting duct is a transition region termed the connecting segment or connecting tubule (CNT). Considerable structural heterogeneity exists along the collecting duct within the two major cell populations, the intercalated cells and the principal cells. In the CNT, the ICT, and the CCD, potassium loading and mineralocorticoids stimulate Na-K-ATPase activity and cause proliferation of the basolateral membrane of CNT cells and principal cells, thus identifying the cells responsible for mineralocorticoid-stimulated potassium secretion in these regions. Finally, at least two morphologically distinct populations of intercalated cells exist, types A and B. In the rat, type A predominates in the CNT and the OMCD and is believed to be responsible for H+ secretion, at least in the OMCD. Type B predominates in the CCD, where it may be involved in bicarbonate secretion.

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