scholarly journals Distinguishing roles of the membrane-cytoskeleton and cadherin mediated cell-cell adhesion in generating different Na+,K(+)-ATPase distributions in polarized epithelia.

1993 ◽  
Vol 123 (1) ◽  
pp. 149-164 ◽  
Author(s):  
J A Marrs ◽  
E W Napolitano ◽  
C Murphy-Erdosh ◽  
R W Mays ◽  
L F Reichardt ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Cell Adhesion ◽  
Choroid Plexus ◽  
High Molecular Weight ◽  
Apical Plasma Membrane ◽  
Choroid Plexus Epithelium ◽  
High Molecular Weight Complex ◽  
Membrane Cytoskeleton ◽  
Triton X

In simple epithelia, the distribution of ion transporting proteins between the apical or basal-lateral domains of the plasma membrane is important for determining directions of vectorial ion transport across the epithelium. In the choroid plexus, Na+,K(+)-ATPase is localized to the apical plasma membrane domain where it regulates sodium secretion and production of cerebrospinal fluid; in contrast, Na+,K(+)-ATPase is localized to the basal-lateral membrane of cells in the kidney nephron where it regulates ion and solute reabsorption. The mechanisms involved in restricting Na+,K(+)-ATPase distribution to different membrane domains in these simple epithelia are poorly understood. Previous studies have indicated a role for E-cadherin mediated cell-cell adhesion and membrane-cytoskeleton (ankyrin and fodrin) assembly in regulating Na+,K(+)-ATPase distribution in absorptive kidney epithelial cells. Confocal immunofluorescence microscopy reveals that in chicken and rat choroid plexus epithelium, fodrin, and ankyrin colocalize with Na+,K(+)-ATPase at the apical plasma membrane, but fodrin, ankyrin, and adducin also localize at the lateral plasma membrane where Na+,K(+)-ATPase is absent. Biochemical analysis shows that fodrin, ankyrin, and Na+,K(+)-ATPase are relatively resistant to extraction from cells in buffers containing Triton X-100. The fractions of Na+,K(+)-ATPase, fodrin, and ankyrin that are extracted from cells cosediment in sucrose gradients at approximately 10.5 S. Further separation of the 10.5 S peak of proteins by electrophoresis in nondenaturing polyacrylamide gels revealed that fodrin, ankyrin, and Na+,K(+)-ATPase comigrate, indicating that these proteins are in a high molecular weight complex similar to that found previously in kidney epithelial cells. In contrast, the anion exchanger (AE2), a marker protein of the basal-lateral plasma membrane in the choroid plexus, did not cosediment in sucrose gradients or comigrate in nondenaturing polyacrylamide gels with the complex of Na+,K(+)-ATPase, ankyrin, and fodrin. Ca(++)-dependent cell adhesion molecules (cadherins) were detected at lateral membranes of the choroid plexus epithelium and colocalized with a distinct fraction of ankyrin, fodrin, and adducin. Cadherins did not colocalize with Na+,K(+)-ATPase and were absent from the apical membrane. The fraction of cadherins that was extracted with buffers containing Triton X-100 cosedimented with ankyrin and fodrin in sucrose gradients and comigrated in nondenaturing gels with ankyrin and fodrin in a high molecular weight complex. Since a previous study showed that E-cadherin is an instructive inducer of Na+,K(+)-ATPase distribution, we examined protein distributions in fibroblasts transfected with B-cadherin, a prominent cadherin expressed in the choroid plexus epithelium.(ABSTRACT TRUNCATED AT 400 WORDS)

Distribution of sodium transporters and aquaporin-1 in the human choroid plexus

2006 ◽  
Vol 291 (1) ◽  
pp. C59-C67 ◽  
Author(s):  
Jeppe Praetorius ◽  
Søren Nielsen
Keyword(s):  
Plasma Membrane ◽  
Choroid Plexus ◽  
Water Channel ◽  
Apical Plasma Membrane ◽  
Membrane Domain ◽  
Choroid Plexus Epithelium ◽  
Human Choroid Plexus ◽  
Fluid Production ◽  
Species Pattern ◽  
Plasma Membrane Domain

The choroid plexus epithelium secretes electrolytes and fluid in the brain ventricular lumen at high rates. Several channels and ion carriers have been identified as likely mediators of this transport in rodent choroid plexus. This study aimed to map several of these proteins to the human choroid plexus. Immunoperoxidase-histochemistry was employed to determine the cellular and subcellular localization of the proteins. The water channel, aquaporin (AQP) 1, was predominantly situated in the apical plasma membrane domain, although distinct basolateral and endothelial immunoreactivity was also observed. The Na+-K+-ATPase α1-subunit was exclusively localized apically in the human choroid plexus epithelial cells. Immunoreactivity for the Na+-K+-2Cl− cotransporter, NKCC1, was likewise confined to the apical plasma membrane domain of the epithelium. The Cl−/HCO3− exchanger, AE2, was localized basolaterally, as was the Na+-dependent Cl−/HCO3− exchanger, NCBE, and the electroneutral Na+-HCO3− cotransporter, NBCn1. No immunoreactivity was found toward the Na+-dependent acid/base transporters NHE1 or NBCe2. Hence, the human choroid plexus epithelium displays an almost identical distribution pattern of water channels and Na+ transporters as the rat and mouse choroid plexus. This general cross species pattern suggests central roles for these transporters in choroid plexus functions such as cerebrospinal fluid production.

A modified procedure for studying enzyme secretion in yeast sphaeroplasts: subcellular distribution of invertase

1976 ◽  
Vol 22 (7) ◽  
pp. 989-995 ◽  
Author(s):  
Bruce E. Holbein ◽  
Cecil W. Forsberg ◽  
Denis K. Kidby
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
High Molecular Weight ◽  
Subcellular Distribution ◽  
Invertase Activity ◽  
Enzyme Secretion ◽  
Low Molecular Weight ◽  
Triton X

A significantly modified procedure for investigating enzyme secretion from yeast sphaeroplasts, and results from its application are described. Sphaeroplasts were derepressed for invertase biosynthesis in the presence of helicase and fractionated to reveal the distribution of high and low molecular weight forms of invertase. Secreted enzyme was found to be of high molecular weight, exclusively. Less than 10% of the total invertase activity was present in washed sphaeroplasts and of this, 43% was soluble, consisting of both high and low molecular weight forms of invertase. Washed membranes retained 32% of the internal invertase activity, and on solubilization with Triton X-100 the enzyme was found to be of an intermediate molecular weight. These results are consistent with the hypothesis that invertase is glycosylated at the plasma membrane.

scholarly journals Characterization of glycoconjugates of human gastrointestinal mucosa by lectins. II. Lectin binding to the isolated glycoproteins of normal and malignant gastric mucosa.

1984 ◽  
Vol 32 (7) ◽  
pp. 690-696 ◽  
Author(s):  
J Fischer ◽  
G Uhlenbruck ◽  
P J Klein ◽  
M Vierbuchen ◽  
R Fischer
Keyword(s):  
Molecular Weight ◽  
Gastric Mucosa ◽  
High Molecular Weight ◽  
Lectin Binding ◽  
Gel Filtration ◽  
Molar Ratio ◽  
Gastric Cancer Cells ◽  
Tissue Sections ◽  
Gradient Gel Electrophoresis ◽  
Triton X

Using affinity chromatography on HPA-, PNA-, Con A, and WGA-agarose columns only a part (10-30%) of the high molecular weight mucous glycoproteins could be isolated from the Triton X-100 solubilized components of normal as well as carcinomatous gastric mucosa. The main part of the mucus was not bound by the lectins, which corresponds to our earlier lectin histochemical observations on paraffin-embedded tissue sections. The lectin-bound mucous glycoproteins had a relatively lower molecular weight, ranging from about 250-1,000 kilodaltons, as indicated by polyacrylamide gradient gel electrophoresis and by gel filtration on Biogel A 1.5 m column. In gas chromatographic analysis the molar ratio of aminohexoses to galactose was found to be much higher (3:1) in the lectin-bound mucous substances than in the whole high molecular weight mucus (1:1). This finding indicates that lectins have a higher affinity to the hexosamine rich components of mucus, which may be special forms of mucous glycoprotein molecules or the incompletely glycosylated core and backbone regions of the oligosaccharide chains of mucus. Extremely high hexosamine values (10:1) were found in the PNA isolated mucus of gastric adenocarcinoma. Since it is known that PNA binds to the terminal disaccharide, beta-galactose-(1-3)-N-acetylgalactosamine, which is localized at the reducing end of the oligosaccharide chains of mucus, it is highly probable that the elongation of the oligosaccharide side chains is disturbed in gastric cancer cells.

P4-129 Genetic study of APH-1 and PEN-2, components of presenilin high molecular weight complex

2004 ◽  
Vol 25 ◽  
pp. S512
Author(s):  
Toshitaka Kawarai ◽  
Antonio Orlacchio ◽  
Ekaterina Rogaeva ◽  
Susan Ling ◽  
Hiroshi Hasegawa ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Genetic Study ◽  
High Molecular Weight Complex

scholarly journals High molecular weight complex of tyrosyl-tRNA synthetase from bovine liver

1991 ◽  
Vol 7 (1) ◽  
pp. 63-69 ◽  
Author(s):  
D. V. Gnatenko ◽  
A. I. Kornelyuk ◽  
I. V. Kurochkin ◽  
G. H. Matsuka
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Bovine Liver ◽  
Trna Synthetase ◽  
High Molecular Weight Complex

The 70-kilodalton adenylyl cyclase-associated protein is not essential for interaction of Saccharomyces cerevisiae adenylyl cyclase with RAS proteins

1992 ◽  
Vol 12 (11) ◽  
pp. 4937-4945
Author(s):  
J Wang ◽  
N Suzuki ◽  
T Kataoka
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Adenylyl Cyclase ◽  
High Molecular Weight ◽  
Size Difference ◽  
Missense Mutations ◽  
Ras Proteins ◽  
High Molecular Weight Complex ◽  
Ras Protein ◽  
Dependent Activity

In the yeast Saccharomyces cerevisiae, adenylyl cyclase is regulated by RAS proteins. We show here that the yeast adenylyl cyclase forms at least two high-molecular-weight complexes, one with the RAS protein-dependent adenylyl cyclase activity and the other with the Mn(2+)-dependent activity, which are separable by their size difference. The 70-kDa adenylyl cyclase-associated protein (CAP) existed in the former complex but not in the latter. Missense mutations in conserved motifs of the leucine-rich repeats of the catalytic subunit of adenylyl cyclase abolished the RAS-dependent activity, which was accompanied by formation of a very high molecular weight complex having the Mn(2+)-dependent activity. Contrary to previous results, disruption of the gene encoding CAP did not alter the extent of RAS protein-dependent activation of adenylyl cyclase, while a concomitant decrease in the size of the RAS-responsive complex was observed. These results indicate that CAP is not essential for interaction of the yeast adenylyl cyclase with RAS proteins even though it is an inherent component of the RAS-responsive adenylyl cyclase complex.

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