Turnover of intestinal brush-border proteins during postnatal development in rat

1980 ◽  
Vol 239 (6) ◽  
pp. G524-G531
Author(s):  
B. Seetharam ◽  
K. Y. Yeh ◽  
D. H. Alpers
Keyword(s):  
Postnatal Development ◽  
Brush Border ◽  
Cathepsin B ◽  
Leucine Incorporation ◽  
Turnover Rates ◽  
Distal Intestine ◽  
Rapid Turnover ◽  
Intestinal Brush Border ◽  
Proximal Intestine

Protein turnover in brush-border membranes of rats during postnatal development has been studied by the double isotope technique. Unlike adult animals where only large proteins (mol wt > 140,000) show relatively rapid turnover, most brush-border proteins in 12-day-old rats show high 3H-to-14C ratios of leucine incorporation, consistent with rapid turnover. Lysosomal proteases, including cathepsin B, are partly responsible for this rapid turnover. This conclusion is based on the following findings: 1) In vivo treatment of 12-day-old animals with leupeptin, an inhibitor of cathepsin B, alters relative turnover rates, enzyme activity, and content of many brush-border proteins. Activities of maltase and trehalase rise while lactase falls. 2) Cathepsin B activity falls rapidly in intestine after the animals are 16 days of age, at a time when luminal pancreatic proteases are rising. Moreover, cathepsin B activity shows less latency in distal intestine at 12 and 16 days than at later ages or in proximal intestine. It is suggested that during postnatal development lysosomal enzymes, e.g., cathepsin B, play an important role in the turnover of intestinal brush-border proteins.

scholarly journals Plastin 1 Binds to Keratin and Is Required for Terminal Web Assembly in the Intestinal Epithelium

2009 ◽  
Vol 20 (10) ◽  
pp. 2549-2562 ◽  
Author(s):  
Eva-Maria S. Grimm-Günter ◽  
Céline Revenu ◽  
Sonia Ramos ◽  
Ilse Hurbain ◽  
Neil Smyth ◽  
...  
Keyword(s):  
Brush Border ◽  
Actin Filaments ◽  
Keratin 19 ◽  
Terminal Web ◽  
Intestinal Brush Border ◽  
Important Regulator ◽  
Increased Sensitivity ◽  
Filament Network ◽  
Deficient Mice

Plastin 1 (I-plastin, fimbrin) along with villin and espin is a prominent actin-bundling protein of the intestinal brush border microvilli. We demonstrate here that plastin 1 accumulates in the terminal web and interacts with keratin 19, possibly contributing to anchoring the rootlets to the keratin network. This prompted us to investigate the importance of plastin 1 in brush border assembly. Although in vivo neither villin nor espin is required for brush border structure, plastin 1-deficient mice have conspicuous ultrastructural alterations: microvilli are shorter and constricted at their base, and, strikingly, their core actin bundles lack true rootlets. The composition of the microvilli themselves is apparently normal, whereas that of the terminal web is profoundly altered. Although the plastin 1 knockout mice do not show any overt gross phenotype and present a normal intestinal microanatomy, the alterations result in increased fragility of the epithelium. This is seen as an increased sensitivity of the brush border to biochemical manipulations, decreased transepithelial resistance, and increased sensitivity to dextran sodium sulfate-induced colitis. Plastin 1 thus emerges as an important regulator of brush border morphology and stability through a novel role in the organization of the terminal web, possibly by connecting actin filaments to the underlying intermediate filament network.

Postnatal ontogeny of intestinal GCPII and the RFC in pig

2009 ◽  
Vol 296 (3) ◽  
pp. G476-G481 ◽  
Author(s):  
Tracy B. Shafizadeh ◽  
Charles H. Halsted
Keyword(s):  
Small Intestine ◽  
Postnatal Development ◽  
Brush Border ◽  
Postnatal Ontogeny ◽  
Study Objective ◽  
Intestinal Brush Border ◽  
Mrna Transcripts ◽  
Yorkshire Pigs ◽  
Folate Hydrolase ◽  
Liver Folate

In humans and pigs, hydrolysis of dietary polyglutamyl folates is carried out by intestinal brush border folate hydrolase [glutamate carboxypeptidase II (GCPII)], whereas the transport of the monoglutamyl folate derivatives occurs via the intestinal brush border reduced folate carrier (RFC). The study objective was to measure the expression of intestinal GCPII and RFC during postnatal development of pigs and their effects on plasma and liver folate concentrations. Duodenum, jejunum, ileum, liver, and plasma samples were collected from female Yorkshire pigs at birth, 24 h, 1 wk, 3 wk, and 6 mo ( n = 6 at each time point). GCPII mRNA transcripts and protein (normalized using β-actin), and enzyme activity (normalized per mg mucosal protein) were highest in all segments of small intestine at birth and were undetectable in ileum after 1 wk, whereas jejunal protein and activity predominated at 6 mo. RFC mRNA transcripts were present in all segments of small intestine at birth and declined significantly throughout development to 6 mo. Conversely, RFC protein increased twofold during the first 24 h and remained constant throughout development in all segments of small intestine. Liver RFC mRNA transcripts were detected at birth but were reduced by 6 mo. Liver folate concentration increased throughout postnatal development, whereas plasma folate levels increased during the first 24 h but decreased over time, reflecting the pattern of RFC expression in small intestine. These findings show that intestinal GCPII and intestinal and hepatic RFC all exhibit ontogenic changes in the pig that are reflected in postnatal folate status.

Effect of hydrocortisone on the desialylation of intestinal brush-border enzymes of the rat during postnatal development

FEBS Letters ◽  
1984 ◽  
Vol 172 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Jiří Kraml ◽  
Jiřina Kolínská ◽  
Libuše Kadlecová ◽  
Marie Zákostelecká ◽  
Zdeněk Lojda
Keyword(s):  
Postnatal Development ◽  
Brush Border ◽  
Brush Border Enzymes ◽  
Intestinal Brush Border ◽  
Intestinal Brush Border Enzymes

Characterization and modulation of rat small intestinal brush-border membrane transbilayer fluidity

1991 ◽  
Vol 260 (4) ◽  
pp. G586-G594
Author(s):  
P. K. Dudeja ◽  
R. K. Wali ◽  
J. M. Harig ◽  
T. A. Brasitus
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Leucine Aminopeptidase ◽  
Aminopeptidase Activity ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Leucine Transport ◽  
Small Intestinal

In the present experiments, selective quenching by trinitrophenyl groups as well as steady-state fluorescence polarization and differential polarized phase fluorescence techniques, using three different lipid soluble fluorophores, were used to directly examine the fluidity of the exofacial and cytofacial leaflets of rat small intestinal brush-border membranes. These studies revealed that the fluidity of the exofacial hemileaflet was greater than the cytofacial hemileaflet. Differences in the distribution of phosphatidylcholine and phosphatidylethanolamine, as assessed by phospholipase A2 treatment and trinitrophenylation of aminophospholipids, were, at least partially, responsible for the asymmetrical fluidity of the hemileaflets. Moreover, in vitro addition of benzyl alcohol (final concn 25 mM) preferentially fluidized the exofacial leaflet and concomitantly decreased leucine aminopeptidase activity but did not affect the activities of maltase, sucrase, alkaline phosphatase, or gamma-glutamyltranspeptidase. In vivo addition of the membrane-mobility agent 2-(2-methoxyethoxy)ethyl 8-(cis-2-n-octylcyclopropyl)octanate] (A2C) (final concn 7.5 microM) preferentially fluidized the cytofacial leaflet and increased Na(+)-gradient-dependent D-glucose transport but not Na(+)-gradient-dependent L-leucine transport.

scholarly journals Galectin-4 and Small Intestinal Brush Border Enzymes Form Clusters

1997 ◽  
Vol 8 (11) ◽  
pp. 2241-2251 ◽  
Author(s):  
E. Michael Danielsen ◽  
Bo van Deurs
Keyword(s):  
Brush Border ◽  
Gradient Centrifugation ◽  
Subcellular Fractionation ◽  
Aminopeptidase N ◽  
Intestinal Lumen ◽  
Immunogold Electron Microscopy ◽  
Brush Border Enzymes ◽  
Intestinal Brush Border ◽  
Mucosal Explants

Detergent-insoluble complexes prepared from pig small intestine are highly enriched in several transmembrane brush border enzymes including aminopeptidase N and sucrase-isomaltase, indicating that they reside in a glycolipid-rich environment in vivo. In the present work galectin-4, an animal lectin lacking a N-terminal signal peptide for membrane translocation, was discovered in these complexes as well, and in gradient centrifugation brush border enzymes and galectin-4 formed distinct soluble high molecular weight clusters. Immunoperoxidase cytochemistry and immunogold electron microscopy showed that galectin-4 is indeed an intestinal brush border protein; we also localized galectin-4 throughout the cell, mainly associated with membraneous structures, including small vesicles, and to the rootlets of microvillar actin filaments. This was confirmed by subcellular fractionation, showing about half the amount of galectin-4 to be in the microvillar fraction, the rest being associated with insoluble intracellular structures. A direct association between the lectin and aminopeptidase N was evidenced by a colocalization along microvilli in double immunogold labeling and by the ability of an antibody to galectin-4 to coimmunoprecipitate aminopeptidase N and sucrase-isomaltase. Furthermore, galectin-4 was released from microvillar, right-side-out vesicles as well as from mucosal explants by a brief wash with 100 mM lactose, confirming its extracellular localization. Galectin-4 is therefore secreted by a nonclassical pathway, and the brush border enzymes represent a novel class of natural ligands for a member of the galectin family. Newly synthesized galectin-4 is rapidly “trapped” by association with intracellular structures prior to its apical secretion, but once externalized, association with brush border enzymes prevents it from being released from the enterocyte into the intestinal lumen.

scholarly journals The effects of dietary ligands on zinc uptake at the porcine intestinal brush-border membrane

1990 ◽  
Vol 64 (3) ◽  
pp. 733-741 ◽  
Author(s):  
A. J. Turnbull ◽  
P. Blakeborough ◽  
R. P. H. Thompson
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Zn Uptake ◽  
Zn Concentration ◽  
Vitro Model

Intestinal brush-border-membrane vesicles were prepared from the porcine small bowel by magnesium precipitation and differential centrifugation, and were functionally intact. The influence of dietary ligands on 65Zn uptake was determined using a 65Zn concentration of 5 μm, an incubation time of 1 min and a reaction temperature of 27°, with a rapid filtration technique. At this low Zn concentration the addition of an excess of folate, histidine or glucose had no effect on Zn uptake. Addition of picolinate, citrate and phytate to the incubation medium significantly reduced Zn uptake at all concentrations of ligand examined. Any inhibitory effects of folic acid in vivo may thuss be due to a mucosal rather than lumen interaction. Those ligands inhibiting absorption may have done so through the formation of Zn-ligand complexes, which are either insoluble, or which reduce the binding of Zn to its mucosal receptor. This in vitro model of Zn absorption is useful for comparing the effects of potential Zn-binding ligands in the diet.

Transport of guanidine in rabbit intestinal brush-border membrane vesicles

1988 ◽  
Vol 255 (1) ◽  
pp. G85-G92 ◽  
Author(s):  
Y. Miyamoto ◽  
V. Ganapathy ◽  
F. H. Leibach
Keyword(s):  
Brush Border ◽  
Time Course ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Extracellular Ph ◽  
Brush Border Membrane Vesicles ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Dependent Transport ◽  
Proximal Intestine

The characteristics of guanidine uptake were studied in brush-border membrane vesicles isolated from the rabbit proximal intestine. Guanidine uptake was manyfold greater in the presence of an outward-directed H+ gradient (intracellular pH = 5.5; extracellular pH = 7.2) than in the absence of a H+ gradient (intracellular and extracellular pH = 7.2). The time course of guanidine uptake exhibited an overshoot phenomenon in the presence of the H+ gradient, indicating occurrence of uphill transport. This H+ gradient-stimulated guanidine uptake was not due to an inside-negative H+-diffusion potential because carbonyl cyanide 4-trifluoromethoxyphenylhydrazone, a protonophore, failed to have any effect on guanidine uptake. Moreover, the transient uphill transport of guanidine was observed even in voltage-clamped membrane vesicles. However, under the conditions that effectively dissipated the H+ gradient, there was no active transport of guanidine. This H+ gradient-dependent transport mechanism for guanidine is distinct from the Na+-H+ exchanger, because amiloride did not inhibit guanidine uptake even at a concentration as high as 100 microM. These data provide evidence for the presence of a guanidine-H+ antiport system in the rabbit intestinal brush-border membrane. The presence of a carrier for guanidine in these membranes is further substantiated by the trans-stimulation of the uptake of radiolabeled guanidine by unlabeled guanidine and by the inhibition of guanidine uptake by imipramine under equilibrium exchange conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

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