scholarly journals Polarized distribution of actin isoforms in gastric parietal cells.

1995 ◽  
Vol 6 (5) ◽  
pp. 541-557 ◽  
Author(s):  
X Yao ◽  
C Chaponnier ◽  
G Gabbiani ◽  
J G Forte
Keyword(s):  
Epithelial Cells ◽  
Basolateral Membrane ◽  
Parietal Cells ◽  
Gastric Epithelial Cells ◽  
Intense Staining ◽  
Actin Isoforms ◽  
Specific Antibodies ◽  
Beta Actin ◽  
Actin Isoform ◽  
Gastric Parietal Cells

The actin genes encode several structurally similar, but perhaps functionally different, protein isoforms that mediate contractile function in muscle cells and determine the morphology and motility in nonmuscle cells. To reveal the isoform profile in the gastric monomeric actin pool, we purified actin from the cytosol of gastric epithelial cells by DNase I affinity chromatography followed by two-dimensional gel electrophoresis. Actin isoforms were identified by Western blotting with a monoclonal antibody against all actin isoforms and two isoform-specific antibodies against cytoplasmic beta-actin and gamma-actin. Densitometry revealed a ratio for beta-actin/gamma-actin that equaled 0.73 +/- 0.09 in the cytosol. To assess the distribution of actin isoforms in gastric glandular cells in relation to ezrin, a putative membrane-cytoskeleton linker, we carried out double immunofluorescence using actin-isoform-specific antibodies and ezrin antibody. Immunostaining confirmed that ezrin resides mainly in canaliculi and apical plasma membrane of parietal cells. Staining for the beta-actin isoform was intense along the entire gland lumen and within the canaliculi of parietal cells, thus predominantly near the apical membrane of all gastric epithelial cells, although lower levels of beta-actin were also identified near the basolateral membrane. The gamma-actin isoform was distributed heavily near the basolateral membrane of parietal cells, with much less intense staining of parietal cell canaliculi and no staining of apical membranes. Within parietal cells, the cellular localization of beta-actin, but not gamma-actin, isoform superimposed onto that of ezrin. In a search for a possible selective interaction between actin isoforms and ezrin, we carried out immunoprecipitation experiments on gastric membrane extracts in which substantial amounts of actin were co-eluted with ezrin from an anti-ezrin affinity column. The ratio of beta-actin/gamma-actin in the immunoprecipitate (beta/gamma = 2.14 +/- 0.32) was significantly greater than that found in the cytosolic fraction. In summary, we have shown that beta- and gamma-actin isoforms are differentially distributed in gastric parietal cells. Furthermore, our data suggest a preferential, but not exclusive, interaction between beta-actin and ezrin in gastric parietal cells. Finally, our results suggest that the beta- and gamma-actin-based cytoskeleton networks might function separately in response to the stimulation of acid secretion.

scholarly journals Polarized Distribution of IQGAP Proteins in Gastric Parietal Cells and Their Roles in Regulated Epithelial Cell Secretion

2003 ◽  
Vol 14 (3) ◽  
pp. 1097-1108 ◽  
Author(s):  
Rihong Zhou ◽  
Zhen Guo ◽  
Charles Watson ◽  
Emily Chen ◽  
Rong Kong ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Actin Cytoskeleton ◽  
Acid Secretion ◽  
Rho Gtpase ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Parietal Cells ◽  
Actin Dynamics ◽  
Cell Secretion ◽  
Gastric Parietal Cells

Actin cytoskeleton plays an important role in the establishment of epithelial cell polarity. Cdc42, a member of Rho GTPase family, modulates actin dynamics via its regulators, such as IQGAP proteins. Gastric parietal cells are polarized epithelial cells in which regulated acid secretion occurs in the apical membrane upon stimulation. We have previously shown that actin isoforms are polarized to different membrane domains and that the integrity of the actin cytoskeleton is essential for acid secretion. Herein, we show that Cdc42 is preferentially distributed to the apical membrane of gastric parietal cells. In addition, we revealed that two Cdc42 regulators, IQGAP1 and IQGAP2, are present in gastric parietal cells. Interestingly, IQGAP2 is polarized to the apical membrane of the parietal cells, whereas IQGAP1 is mainly distributed to the basolateral membrane. An IQGAP peptide that competes with full-length IQGAP proteins for Cdc42-binding in vitro also inhibits acid secretion in streptolysin-O-permeabilized gastric glands. Furthermore, this peptide disrupts the association of IQGAP and Cdc42 with the apical actin cytoskeleton and prevents the apical membrane remodeling upon stimulation. We propose that IQGAP2 forms a link that associates Cdc42 with the apical cytoskeleton and thus allows for activation of polarized secretion in gastric parietal cells.

scholarly journals Prostaglandin E2-Activated Housekeeping Cl- Channels in the Basolateral Membrane of Rat Gastric Parietal Cells.

1999 ◽  
Vol 49 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Akira IKARI ◽  
Hideki SAKAI ◽  
Akiko TANAKA ◽  
Atsushi IKEDA ◽  
Kanako INOUE ◽  
...  
Keyword(s):  
Prostaglandin E2 ◽  
Basolateral Membrane ◽  
Parietal Cells ◽  
Cl Channels ◽  
Gastric Parietal Cells

Sorting of actin isoforms in chicken auditory hair cells

1997 ◽  
Vol 110 (6) ◽  
pp. 765-770 ◽  
Author(s):  
D. Hofer ◽  
W. Ness ◽  
D. Drenckhahn
Keyword(s):  
Actin Filament ◽  
Hair Cells ◽  
Auditory Hair Cells ◽  
Actin Isoforms ◽  
Cytoplasmic Actin ◽  
Beta Actin ◽  
Nonmuscle Cells ◽  
Filament Bundles ◽  
Actin Isoform ◽  
Cellular Compartments

Most nonmuscle cells of higher vertebrates contain two different actin isoforms, beta- and gamma-cytoplasmic actin. The beta-isoform is with few exceptions the predominant isoform in nonmuscle cells and tissues. Perturbation of the beta:gamma ratio has been shown to affect the organization of bundled actin filaments indicating that the beta- and gamma-genes encode functionally distinct cytoarchitectural information. In the present study we localized by immunostaining beta- and gamma-actin in chicken auditory hair cells. These highly specialized cells serve as model system for studying certain developmental and structural aspects of a complex actin filament system with high architectural precision. We show that gamma-actin is the predominant actin isoform in auditory hair cells with an apparent beta:gamma ratio of approximately 1:2. gamma-Actin is not sorted and occurs in all three actin assemblies of the hair border, i.e. the cores of sensory hairs (stereocilia), the subjacent gel-like actin filament meshwork (cuticular plate) and the zonula adherens ring. In contrast to gamma-actin, the beta-isoform is specifically sorted to the actin filament core bundle of stereocilia that is extensively crosslinked by fimbrin. In view of recent studies showing that L-plastin, the leukocyte homolog of fimbrin, has a higher binding affinity for beta-actin than for gamma-actin, a mechanism is proposed for how hair cells might restrict formation of actin filament bundles to a single cellular site (i.e. the stereocilia). The limited level of expression of beta-actin in hair cells may help to prevent ectopic bundle formation in other cellular compartments.

scholarly journals Effects of IL-1β on the proliferation and apoptosis of gastric epithelial cells and acid secretion from isolated rabbit parietal cells

2012 ◽  
Vol 7 (1) ◽  
pp. 299-305 ◽  
Author(s):  
TAO GUO ◽  
JIA-MING QIAN ◽  
YU-QING ZHAO ◽  
XIAO-BO LI ◽  
JIAN-ZHONG ZHANG
Keyword(s):  
Epithelial Cells ◽  
Acid Secretion ◽  
Parietal Cells ◽  
Gastric Epithelial Cells ◽  
Proliferation And Apoptosis

Role of vacuolation in the death of gastric epithelial cells

1997 ◽  
Vol 272 (1) ◽  
pp. C48-C58 ◽  
Author(s):  
S. J. Hagen ◽  
S. Takahashi ◽  
R. Jansons
Keyword(s):  
Epithelial Cells ◽  
Cell Survival ◽  
Potent Inhibitor ◽  
Chief Cell ◽  
Parietal Cells ◽  
Gastric Epithelial Cells ◽  
Bafilomycin A1 ◽  
Gastric Glands ◽  
Chief Cells

The effect of vacuolation on survival of gastric epithelial cells was studied in rabbit gastric glands (RGG) incubated with ammonia and bafilomycin A1, a potent inhibitor of vacuolar ATPase activity. In ammonia, large vacuoles formed and cell survival was reduced to 47.2 +/- 3.4% at 6 h (59.5 +/- 3.8%, buffer). Bafilomycin A1 added at the start to RGG incubated with ammonia inhibited vacuole formation but did not improve cell survival (48.7 +/- 2.8% at 6 h). Bafilomycin A1 added 1-2 h after addition of ammonia reduced the size of vacuoles but did not alter cell survival. Cell survival was not affected by inhibiting protein synthesis. When incubated with ammonia, parietal cells dissociated from the gland and ruptured. After this, chief cells condensed and formed expensive blebs that contained fragmented nuclei. We conclude that 1)ammonia-induced vacuolation of gastric epithelial cells does not influence cell survival, 2) ammonia facilitates necrosis in parietal cells and apoptosis in chief cells, and 3) chief cell survival, in some manner, may be dependent on parietal cells.

Prostaglandin E2 output by isolated rat gastric parietal cells and non-parietal epithelial cells

1988 ◽  
Vol 36 (5) ◽  
pp. 589-600 ◽  
Author(s):  
S. Ota ◽  
M. Razandi ◽  
W. Krause ◽  
A. Terano ◽  
H. Hiraishi ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Prostaglandin E2 ◽  
Parietal Cells ◽  
Parietal Epithelial Cells ◽  
Gastric Parietal Cells ◽  
Isolated Rat

Identification of a basolateral Cl−/HCO 3 − exchanger specific to gastric parietal cells

2003 ◽  
Vol 284 (6) ◽  
pp. G1093-G1103 ◽  
Author(s):  
Snezana Petrovic ◽  
Xie Ju ◽  
Sharon Barone ◽  
Ursula Seidler ◽  
Seth L. Alper ◽  
...  
Keyword(s):  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Basolateral Membrane ◽  
Parietal Cells ◽  
Rt Pcr ◽  
Functional Studies ◽  
Distribution Studies ◽  
Immunofluorescence Labeling ◽  
Gastric Parietal Cells

The basolateral Cl−/HCO[Formula: see text] exchanger in parietal cells plays an essential role in gastric acid secretion mediated via the apical gastric H+-K+-ATPase. Here, we report the identification of a new Cl−/HCO[Formula: see text]exchanger, which shows exclusive expression in mouse stomach and kidney, with expression in the stomach limited to the basolateral membrane of gastric parietal cells. Tissue distribution studies by RT-PCR and Northern hybridizations demonstrated the exclusive expression of this transporter, also known as SLC26A7, to stomach and kidney, with the stomach expression significantly more abundant. No expression was detected in the intestine. Cellular distribution studies by RT-PCR and Northern hybridizations demonstrated predominant localization of SLC26A7 in gastric parietal cells. Immunofluorescence labeling localized this exchanger exclusively to the basolateral membrane of gastric parietal cells, and functional studies in oocytes indicated that SLC26A7 is a DIDS-sensitive Cl−/HCO[Formula: see text] exchanger that is active in both acidic and alkaline pHi. On the basis of its unique expression pattern and function, we propose that SLC26A7 is a basolateral Cl−/HCO[Formula: see text] exchanger in gastric parietal cells and plays a major role in gastric acid secretion.

scholarly journals Sonic hedgehog is associated with H+-K+-ATPase-containing membranes in gastric parietal cells and secreted with histamine stimulation

2008 ◽  
Vol 295 (1) ◽  
pp. G99-G111 ◽  
Author(s):  
Yana Zavros ◽  
Melissa A. Orr ◽  
Chang Xiao ◽  
Danuta H. Malinowska
Keyword(s):  
Sonic Hedgehog ◽  
Proteolytic Enzymes ◽  
Gradient Centrifugation ◽  
Basolateral Membrane ◽  
Gastric Gland ◽  
Parietal Cells ◽  
Human Gastric Cancer ◽  
Gastric Glands ◽  
Α Subunit ◽  
Gastric Parietal Cells

Sonic hedgehog (Shh) is found within gastric parietal cells and processed from a 45-kDa to a 19-kDa bioactive protein by an acid- and protease-dependent mechanism. To investigate whether Shh is associated with the parietal cell membrane compartment that becomes exposed to both acid and proteolytic enzymes during acid secretion, the cellular location of Shh within resting and stimulated gastric parietal cells was examined. Immunofluorescence microscopy of rabbit stomach sections showed that Shh colocalized predominantly with parietal and pit, not chief/zymogen or neck, cell markers. In resting and histamine-stimulated rabbit gastric glands Shh was expressed only in parietal cells close to H+-K+-ATPase-containing tubulovesicular and secretory membranes with some colocalizing with γ-actin at the basolateral membrane. Gastric gland microsomal membranes were prepared by differential and sucrose gradient centrifugation and immunoisolation with an anti-H+-K+-ATPase-α subunit antibody. The 45- and 19-kDa Shh proteins were detected by immunoblot in immunopurified H+-K+-ATPase-containing membranes from resting and stimulated gastric glands, respectively. Incubating glands with a high KCl concentration removed Shh from the membranes. Histamine stimulated 19-kDa Shh secretion from gastric glands into the medium. In human gastric cancer 23132/87 cells cultured on permeable membranes, histamine increased 19-kDa Shh secretion into both apical and basolateral media. These findings show that Shh is a peripheral protein associated with resting and stimulated H+-K+-ATPase-expressing membranes. In addition, Shh appears to be expressed at or close to the basolateral membrane of parietal cells.

scholarly journals Identification of actin from hepatoma Morris 5123 cells.

1999 ◽  
Vol 46 (4) ◽  
pp. 949-959 ◽  
Author(s):  
D Nowak ◽  
A Kochman ◽  
M Malicka-Błaszkiewicz
Keyword(s):  
Gel Electrophoresis ◽  
Dnase I ◽  
2D Gel Electrophoresis ◽  
Muscle Actin ◽  
Actin Isoforms ◽  
Beta Actin ◽  
Sds Page ◽  
Actin Isoform ◽  
2D Gel ◽  
Differential Affinity

The hepatoma Morris 5123 tumor growth is accompanied by changes in actin content and polymerization (Malicka-Błaszkiewicz et al. (1995) Mat. Med. Pol., 27, 115-118; Nowak et al. (1995) J. Exp. Cancer Res. 14, 37-40). Presently actin isoforms from cytosol and cytoskeleton fractions were separated by SDS/PAGE and identified with antibodies directed against different actin isoforms. Actin isolated from the cytosol by affinity chromatography on DNase I bound to agarose shows the presence of only one protein spot on 2D gel electrophoresis corresponding to the mobility of the rabbit a skeletal muscle actin (Mr 43,000) and isoelectric point equal to 5.3. It interacts only with monoclonal anti beta actin isoform antibodies, posing the question of differential affinity of actin isoforms to DNase I.

Actin mRNA isoforms are differentially sorted in normal osteoblasts and sorting is altered in osteoblasts from a skeletal mutation in the rat

1998 ◽  
Vol 111 (9) ◽  
pp. 1287-1292 ◽  
Author(s):  
H. Watanabe ◽  
E.H. Kislauskis ◽  
C.A. Mackay ◽  
A. Mason-Savas ◽  
S.C. Marks
Keyword(s):  
In Situ Hybridization ◽  
Bone Resorption ◽  
Cell Types ◽  
Mrna Isoforms ◽  
Actin Isoforms ◽  
Beta Actin ◽  
Cell Processes ◽  
Actin Mrna ◽  
Actin Isoform

Actin isoform sorting has been shown to occur in a variety of cell types in culture. To this list we add osteoblasts, in which we show by in situ hybridization that beta-actin is distributed primarily in cell processes and on one side of the nucleus and gamma-actin has a perinuclear distribution. Osteoblasts from the skeletal mutation toothless (tl), evaluated under identical conditions, fail to sort these actin isoforms differentially and exhibit diffuse labeling as their major manifestation. Northern analyses of actin mRNAs showed no differences between normal and mutant cultures. Shortened osteoblast life span and an inability to direct osteoclast-mediated bone resorption have recently been demonstrated in tl mutants. The present results suggest that a failure of osteoblasts to sort actin mRNAs may be related to one or both of these pathological manifestations in this mutation and represent, to our knowledge, the first correlation of an actin mRNA-sorting abnormality with a mammalian disease.

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