Patchy accumulation of apical Na+ transporters allows cross talk between extracellular space and cell nucleus.

Oberleithner, Hans; Wünsch, Stefan; Schneider, Stefan W.

doi:10.1073/pnas.89.1.241

Cited by 15 publications

(13 citation statements)

References 21 publications

(27 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several other transport proteins have been shown to have restricted distributions on the surface of epithelial cells. 1) Functional studies by Oberleithner demonstrated that Na ϩ channels in Madin-Darby canine kidney (MDCK) cells had such a central localization (36,39); 2) K ϩ channel, Kv1.4, clustered at the leading edge of migrating MDCK cells (47); 3) NHE1 is localized to pseudopodial protrusions in invasive MDCK cells (28); and 4) Sorribas et al (50) showed that NaPi-2 and NaPi-4 in OK cells were expressed only in the clumped microvilli and were largely excluded from the intermicrovillar clefts. The existence of plasma membrane subdomains has been clearly demonstrated in neurons.…”

Section: Discussionmentioning

confidence: 99%

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Akhter¹,

Kovbasnjuk²,

Li³

et al. 2002

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

Cell biological approaches were used to examine the location and function of the brush border (BB) Na(+)/H(+) exchanger NHE3 in the opossum kidney (OK) polarized renal proximal tubule cell line. NHE3 epitope tagged with the vesicular stomatitis virus glycoprotein epitope (NHE3V) was stably expressed and called OK-E3V cells. On the basis of cell surface biotinylation studies, these cells had 10-15% of total NHE3 on the BB. Intracellular NHE3V largely colocalized with Rab11 and to a lesser extent with EEA1. The BB location of NHE3V was examined by confocal microscopy relative to the lectins wheat germ aggluttinin (WGA) and phytohemagluttin E (PHA-E), as well as the B subunit of cholera toxin (CTB). The cells were pyramidal, and NHE3 was located in microvilli in the center of the apical surface. In contrast, PHA-E, WGA, and CTB were diffusely distributed on the BB. Detergent extraction showed that total NHE3V was largely soluble in Triton X-100, whereas virtually all surface NHE3V was insoluble. Sucrose density gradient centrifugation demonstrated that total NHE3V migrated at the same size as approximately 400- and approximately 900-kDa standards, whereas surface NHE3V was enriched in the approximately 900-kDa form. Under basal conditions, NHE3 cycled between the cell surface and the recycling pathway through a phosphatidylinositol (PI) 3-kinase-dependent mechanism. Measurements of surface and intracellular pH were obtained by using FITC-WGA. Internalization of FITC-WGA occurred largely into the juxtanuclear compartment that contained Rab11 and NHE3V. pH values on the apical surface and in endosomes in the presence of the NHE3 blocker, S3226, were elevated, showing that NHE3 functioned to acidify both compartments. In conclusion, NHE3V in OK cells exists in distinct domains both in the center of the apical surface and in a juxtanuclear compartment. In the BB fraction, NHE3 is largely in the detergent-insoluble fraction in lipid rafts and/or in large heterogenous complexes ranging from approximately 400 to approximately 900 kDa.

show abstract

Section: Discussionmentioning

confidence: 99%

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Akhter¹,

Kovbasnjuk²,

Li³

et al. 2002

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

show abstract

“…That all NHE3 on the apical surface is not equivalent is a new observation and suggests a 'site' that NHE3 initially arrives at as part of recycling. Previously, Oberleithner et al, showed that in renal epithelial cells, renal Na and K channels had a preferential central apical location (Oberleithner et al, 1992;Schwab et al, 1995). We previously suggested there was a similar preferential central apical location for NHE3 in some OK cells (Akhter et al, 2002).…”

Section: Mf Of Yfp-gl-gpi Is Not Dependent On Nherf2 and Is Not Altermentioning

confidence: 96%

The lateral mobility of NHE3 on the apical membrane of renal epithelial OK cells is limited by the PDZ domain proteins NHERF1/2, but is dependent on an intact actin cytoskeleton as determined by FRAP

Cha

Kenworthy

Murtazina

et al. 2004

Journal of Cell Science

View full text Add to dashboard Cite

The epithelial brush border (BB) Na+/H+ exchanger, NHE3, plays a major role in transcellular Na+ absorption in the renal proximal tubule. NHE3 activity is rapidly regulated by neurohumoral substances and growth factors via changes in its amount on the BB by a process partially involving vesicle trafficking. The PDZ domain-containing proteins, NHERF1/2, are scaffold proteins that link NHE3 to the actin cytoskeleton via their binding to both ezrin and NHE3. NHERF1/2 interact with both an internal C-terminal domain of NHE3 and the N-terminus of ezrin. We used fluorescence recovery after photobleaching (FRAP) to study the effect of NHERF1/2 on NHE3 mobility in the brush border of opossum kidney (OK) proximal tubule cells. A confocal microscope was used to allow the selective study of apical membrane versus intracellular NHE3. A chimera of NHE3-EGFP was transiently expressed in OK cells and its lateral diffusion in the apical membrane was measured with FRAP and confocal microscopy at 37°C. The contribution of intracellular NHE3-EGFP to recovery on the OK surface not directly over the juxtanuclear area (non-JN) was negligible as exposure to the water soluble crosslinker BS3 (10 mM) at 4°C resulted in no recovery of this component of surface NHE3-EGFP after photobleaching. The mobile fraction (Mf) of apical NHE3-EGFP was 47.5±2.2%; the effective diffusion coefficient (Deff) was (2.2±0.3) ×10–10 cm2/second. Overexpression of NHERF2 in OK cells decreased the Mf to 29.1±3.1% without changing Deff. In the truncation mutant, NHE3585-EGFP (aa 1-585), which lacks the NHERF1/2 binding domain, Mf increased to 66.4±2.2%, with no change in Deff, whereas NHE3660-EGFP, which binds NHERF1/2, had Mf (48.3±3.0%) and Deff both similar to full-length NHE3. These results are consistent with the PDZ domain proteins NHERF1 and NHERF2 scaffolding NHE3 in macromolecular complexes in the apical membrane of OK cells under basal conditions, which limits the lateral mobility of NHE3. It is probable that this is one of the mechanisms by which NHERF1/2 affects rapid regulation of NHE3 by growth factors and neurohumoral mediators. By contrast, disrupting the actin cytoskeleton by latrunculin B treatment (0.05 μM, 30 minutes) reduced the NHE3 Mf (21.9±4.5%) without altering the Deff. Therefore the actin cytoskeleton, independently of NHERF1/2 binding, is necessary for apical membrane mobility of NHE3.

show abstract

“…3). As is known, potassium is the most widely represented cellular cation, and sodium cations are widely represented in cell nuclei (where their concentration is 10 times greater than in the cytoplasm [9][10][11]. An attempt was made to compare macrostructures of precipitation formed by sodium and potassium salts of DNA.…”

Section: Some Features Of the Formation Of Salt Crystalsmentioning

confidence: 99%

Legends of DNA morphology.

Pivovarenko¹

2018

Morphologia

View full text Add to dashboard Cite

Шановні колеги! У рубриці "Методологія наукових досліджень" редакція продовжує публікацію матеріалів, що пов'язані з найважливішими аспектами наукової і навчальної діяльності: організаційно-методичним забезпеченням періодичних наукових видань, загальними принципами біостатистичного та математичного супроводження досліджень, а також оригінальними методичними підходами вітчизняних і зарубіжних морфологів.

show abstract

Patchy accumulation of apical Na+ transporters allows cross talk between extracellular space and cell nucleus.

Cited by 15 publications

References 21 publications

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

The lateral mobility of NHE3 on the apical membrane of renal epithelial OK cells is limited by the PDZ domain proteins NHERF1/2, but is dependent on an intact actin cytoskeleton as determined by FRAP

Legends of DNA morphology.

Contact Info

Product

Resources

About

Patchy accumulation of apical Na+ transporters allows cross talk between extracellular space and cell nucleus.

Cited by 15 publications

References 21 publications

Na+/H+ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Na+/H+ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

The lateral mobility of NHE3 on the apical membrane of renal epithelial OK cells is limited by the PDZ domain proteins NHERF1/2, but is dependent on an intact actin cytoskeleton as determined by FRAP

Legends of DNA morphology.

Contact Info

Product

Resources

About

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Na⁺/H⁺ exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells