scholarly journals Synthesis of membrane glycoproteins in rat small-intestinal villus cells. Effect of colchicine on the redistribution of l-[1,5,6-3H]fucose-labelled membrane glycoproteins among Golgi, lateral basal and microvillus membranes

1979 ◽  
Vol 182 (1) ◽  
pp. 213-221 ◽  
Author(s):  
A Quaroni ◽  
K Kirsch ◽  
M M Weiser
Keyword(s):  
Golgi Complex ◽  
Basal Part ◽  
Membrane Glycoproteins ◽  
Intestinal Villus ◽  
Microvillus Membrane ◽  
Villus Cell ◽  
Small Intestinal ◽  
Small Intestinal Villus ◽  
Membrane Components

To define the role of cytoplasmic microtubules in the biogenesis of plasmalemma glycoproteins of rat small-intestinal villus cells, we studied the effect of colchicine on the incorporation of L-[1,5,6-3H]fucose into Golgi, lateral basal and microvillus membranes. Colchicine was administered intraperitoneally before or after injection of radioactive fucose. The incorporation of radioactivity into Golgi membranes was little affected by colchicine, which did not prevent the redistribution of most of the labelled glycoproteins from the Golgi complex into other parts of the villus cell. The incorporation of labelled glycoproteins into the microvillus membrane was greatly inhibited by colchicine given 2 h or 10 min before the radioactive fucose: all labelled glycoproteins present in this membrane were equally affected. In contrast, the administration of colchicine considerably increased the incorporation of radioactivity into the lateral basal part of the plasmalemma, and prevented the disappearance of most of the labelled glycoproteins from this membrane at late times after fucose injection. These results suggest that cytoplasmic microtubular structures are important for the polarization of the intestinal villus cell and the biogenesis of the microvillus membrane, although playing little or no role in the movement of membrane components from the Golgi complex to the lateral basal part of the plasmalemma.

scholarly journals Synthesis of membrane glycoproteins in rat small-intestinal villus cells. Redistribution of l-[1,5,6-3H]-fucose-labelled membrane glycoproteins among Golgi, lateral basal and microvillus membranes in vivo

1979 ◽  
Vol 182 (1) ◽  
pp. 203-212 ◽  
Author(s):  
Andrea Quaroni ◽  
Katharina Kirsch ◽  
Milton M. Weiser
Keyword(s):  
Golgi Complex ◽  
Membrane Fraction ◽  
Surface Membrane ◽  
Sodium Dodecyl ◽  
Membrane Glycoproteins ◽  
Intestinal Villus ◽  
Microvillus Membrane ◽  
Small Intestinal ◽  
Small Intestinal Villus

The biogenesis of plasmalemma glycoproteins of rat small-intestinal villus cells was studied by following the incorporation of l-[1,5,6-3H]fucose, given intraperitoneally with and without chase, into Golgi, lateral basal and microvillus membranes. Each membrane fraction showed distinct kinetics of incorporation of labelled fucose and was differently affected by the chase, which produced a much greater decrease in incorporation of label into Golgi and microvillus than into lateral basal membranes. The kinetic data suggest a redistribution of newly synthesized glycoproteins from the site of fucosylation, the Golgi complex, directly into both lateral basal and microvillus membranes. The observed biphasic pattern of label incorporation into the microvillus membrane fraction may be evidence for a second indirect route of incorporation. The selective effect of the chase suggests the presence of two different pools of radioactive fucose in the Golgi complex that differ in (1) their accessibility to dilution with non-radioactive fucose, and (2) their utilization for the biosynthesis of membrane glycoproteins subsequently destined for either the microvillus or the lateral basal parts of the plasmalemma. The radioactively labelled glycoproteins of the different membrane fractions were separated by sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis and identified by fluorography. The patterns of labelled glycoproteins in Golgi and lateral basal membranes were identical at all times. At least 14 bands could be identified shortly after radioactive-fucose injection. Most seemed to disappear at later times, although one of them, which was never observed in microvillus membranes, increased in relative intensity. All but two of the labelled glycoproteins present in the microvillus membrane corresponded to those observed in Golgi and lateral basal membranes shortly after fucose injection. The patterns of labelled glycoproteins in all membrane fractions were little affected by the chase. These data support a flow concept for the insertion of most surface-membrane glycoproteins of the intestinal villus cells.

scholarly journals Identification and characterization of rabbit small intestinal villus cell brush border membrane Na-glutamine cotransporter

2008 ◽  
Vol 295 (1) ◽  
pp. G7-G15 ◽  
Author(s):  
Jamilur R. Talukder ◽  
Ramesh Kekuda ◽  
Prosenjit Saha ◽  
Subha Arthur ◽  
Uma Sundaram
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Intestinal Villus ◽  
Villus Cell ◽  
Small Intestinal ◽  
Small Intestinal Villus ◽  
Glutamine Uptake

Glutamine, the primary metabolic fuel for the mammalian small intestinal enterocytes, is primarily assimilated by Na-amino acid cotransporters. Although Na-solute cotransport has been shown to exist in the brush border membrane (BBM) of the absorptive villus cells, the identity of Na-glutamine cotransport in rabbit small intestinal villus cells was unknown. Na-dependent glutamine uptake is present in villus BBM vesicles. An intravesicular proton gradient did not stimulate this Na-dependent glutamine uptake, whereas Li+ did not significantly suppress this uptake. These observations in concert with amino acid substitution studies suggested that Na-glutamine cotransporter in the villus cell BBM was the newly identified cotransporter B0AT1 (SLC6A19). Quantitative real-time PCR identified the message for this cotransporter in villus cells. Thus a full-length cDNA of B0AT1 was cloned and expressed in MDA-MB-231 cells. This expressed cotransporter exhibited characteristics similar to those observed in villus cells from the rabbit small intestine. Antibody was generated for B0AT1 that demonstrated the presence of this cotransporter protein in the villus cell BBM. Kinetic studies defined the kinetic parameters of this cotransporter. Thus this study describes the identification, cloning, and characterization of the Na-amino acid cotransporter responsible for the assimilation of a critical amino acid by the absorptive villus cells in the mammalian small intestine.

Bitter taste receptor mTas2r105 is expressed in small intestinal villus and crypts

2015 ◽  
Vol 463 (4) ◽  
pp. 934-941 ◽  
Author(s):  
Fu Gu ◽  
Xin Liu ◽  
Jie Liang ◽  
Jiaying Chen ◽  
Fuxue Chen ◽  
...  
Keyword(s):  
Bitter Taste ◽  
Taste Receptor ◽  
Bitter Taste Receptor ◽  
Intestinal Villus ◽  
Small Intestinal ◽  
Small Intestinal Villus

Oral IGF-I enhances nutrient and electrolyte absorption in neonatal piglet intestine

1999 ◽  
Vol 277 (3) ◽  
pp. G619-G625 ◽  
Author(s):  
Andrew N. Alexander ◽  
Hannah V. Carey
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Intestinal Villus ◽  
Ileal Mucosa ◽  
Body Weights ◽  
Igf I ◽  
Small Intestinal ◽  
Small Intestinal Villus ◽  
Mucosal Mass ◽  
And Function

The effect of orally administered insulin-like growth factor-I (IGF-I) on small intestinal structure and function was studied in 5-day-old colostrum-deprived piglets. Human recombinant IGF-I (3.5 mg ⋅ kg−1 ⋅ day−1) or control vehicle was given orogastrically for 4 days. Body weights, jejunal and ileal mucosa wet and dry weights, and serum IGF-I levels were similar in the two groups. Small intestinal villus height and crypt depth and jejunal enterocyte microvillar dimensions were also similar between groups. Oral IGF-I produced higher rates of jejunal ion transport because of increased basal Na+ absorption. Short-circuit current responses to mucosal addition ofd-glucose andl-alanine and net transepithelial absorption of 3- O-methylglucose were increased by IGF-I. Carrier-mediated uptake ofd-glucose per milligram in everted jejunal sleeves was greater in IGF-I-treated piglets because of a significantly greater maximal rate of uptake. We conclude that rates of net Na+ and Na+-dependent nutrient absorption are enhanced in piglets treated with oral IGF-I, and this effect is independent of changes in mucosal mass or surface area.

scholarly journals Physiological relevance of cell-specific distribution patterns of CFTR, NKCC1, NBCe1, and NHE3 along the crypt-villus axis in the intestine

2011 ◽  
Vol 300 (1) ◽  
pp. G82-G98 ◽  
Author(s):  
Robert L. Jakab ◽  
Anne M. Collaco ◽  
Nadia A. Ameen
Keyword(s):  
Membrane Trafficking ◽  
Expression Patterns ◽  
Goblet Cells ◽  
Functional Plasticity ◽  
Intestinal Villus ◽  
Induced Membrane ◽  
Specific Distribution ◽  
Early Endosomes ◽  
Small Intestinal ◽  
Small Intestinal Villus

We examined the cell-specific subcellular expression patterns for sodium- and potassium-coupled chloride (NaK2Cl) cotransporter 1 (NKCC1), Na+bicarbonate cotransporter (NBCe1), cystic fibrosis transmembrane conductance regulator (CFTR), and Na+/H+exchanger 3 (NHE3) to understand the functional plasticity and synchronization of ion transport functions along the crypt-villus axis and its relevance to intestinal disease. In the unstimulated intestine, all small intestinal villus enterocytes coexpressed apical CFTR and NHE3, basolateral NBCe1, and mostly intracellular NKCC1. All (crypt and villus) goblet cells strongly expressed basolateral NKCC1 (at approximately three-fold higher levels than villus enterocytes), but no CFTR, NBCe1, or NHE3. Lower crypt cells coexpressed apical CFTR and basolateral NKCC1, but no NHE3 or NBCe1 (except NBCe1-expressing proximal colonic crypts). CFTR, NBCe1, and NKCC1 colocalized with markers of early and recycling endosomes, implicating endocytic recycling in cell-specific anion transport. Brunner's glands of the proximal duodenum coexpressed high levels of apical/subapical CFTR and basolateral NKCC1, but very low levels of NBCe1, consistent with secretion of Cl−-enriched fluid into the crypt. The cholinergic agonist carbachol rapidly (within 10 min) reduced cell volume along the entire crypt/villus axis and promoted NHE3 internalization into early endosomes. In contrast, carbachol induced membrane recruitment of NKCC1 and CFTR in all crypt and villus enterocytes, NKCC1 in all goblet cells, and NBCe1 in all villus enterocytes. These observations support regulated vesicle traffic in Cl−secretion by goblet cells and Cl−and HCO3−secretion by villus enterocytes during the transient phase of cholinergic stimulation. Overall, the carbachol-induced membrane trafficking profile of the four ion transporters supports functional plasticity of the small intestinal villus epithelium that enables it to conduct both absorptive and secretory functions.

Outwardly rectifying Cl− channel in guinea pig small intestinal villus enterocytes: effect of inhibitors

1997 ◽  
Vol 273 (5) ◽  
pp. G1141-G1152 ◽  
Author(s):  
Alan S. Monaghan ◽  
Gerard M. Mintenig ◽  
Francisco V. Sepúlveda
Keyword(s):  
Inhibitory Concentration ◽  
Single Channel ◽  
Intestinal Villus ◽  
Open Probability ◽  
Outward Currents ◽  
Cell Current ◽  
Excised Patches ◽  
Small Intestinal ◽  
Small Intestinal Villus ◽  
Clamp Study

Previous studies in enterocytes isolated from the villus region of small intestinal epithelium have identified a macroscopic current carried by Cl−. In this work a single-channel patch-clamp study was carried out in the same cells, and a spontaneously active, outwardly rectifying Cl− channel was identified and proposed to underlie the whole cell current. The channel had conductances of 62 and 19 pS at 80 and −80 mV, respectively, in symmetrical Cl− solutions in excised patches. Similar activity was seen in cell-attached patches, but only outward currents could be discerned in this configuration. The activity of the channel, measured as open probability, was independent of intracellular calcium levels and voltage. The selectivity sequence for different anions was SCN− > I− > Br− > Cl− > F− > (gluconate, glutamate, [Formula: see text]). The channel was inhibited by 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), verapamil, and 4-hydroxytamoxifen (but not by tamoxifen), with potencies similar to those observed for Cl− channels previously described in other cells. Inhibition by trinitrophenyladenosine 5′-triphosphate was also observed but only at depolarized potentials. At 50 mV the half-maximal inhibitory concentration was 18 nM. It is proposed that this channel plays a role in transepithelial Cl−transport and certain regulatory Cl− fluxes.

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