Functional characterization of PCFT/HCP1 as the molecular entity of the carrier-mediated intestinal folate transport system in the rat model

2008 ◽  
Vol 294 (3) ◽  
pp. G660-G668 ◽  
Author(s):  
Katsuhisa Inoue ◽  
Yasuhiro Nakai ◽  
Sayaka Ueda ◽  
Shunsuke Kamigaso ◽  
Kin-ya Ohta ◽  
...  
Keyword(s):  
Small Intestine ◽  
Transport System ◽  
Functional Characterization ◽  
Cellular Membrane ◽  
Molecular Entity ◽  
Xenopus Laevis Oocytes ◽  
Rat Small Intestine ◽  
Distribution Profile ◽  
Folate Transport

Proton-coupled folate transporter/heme carrier protein 1 (PCFT/HCP1) has recently been identified as a transporter that mediates the translocation of folates across the cellular membrane by a proton-coupled mechanism and suggested to be the possible molecular entity of the carrier-mediated intestinal folate transport system. To further clarify its role in intestinal folate transport, we examined the functional characteristics of rat PCFT/HCP1 (rPCFT/HCP1) expressed in Xenopus laevis oocytes and compared with those of the carrier-mediated folate transport system in the rat small intestine evaluated by using the everted tissue sacs. rPCFT/HCP1 was demonstrated to transport folate and methotrexate more efficiently at lower acidic pH and, as evaluated at pH 5.5, with smaller Michaelis constant ( Km) for the former (2.4 μM) than for the latter (5.7 μM), indicating its characteristic as a proton-coupled folate transporter that favors folate than methotrexate as substrate. rPCFT/HCP1-mediated folate transport was found to be inhibited by several but limited anionic compounds, such as sulfobromophthalein and sulfasalazine. All these characteristics of rPCFT/HCP1 were in agreement with those of carrier-mediated intestinal folate transport system, of which the Km values were 1.2 and 5.8 μM for folate and methotrexate, respectively, in the rat small intestine. Furthermore, the distribution profile of the folate transport system activity along the intestinal tract was in agreement with that of rPCFT/HCP1 mRNA. This study is the first to clone rPCFT/HCP1, and we successfully provided several lines of evidence that indicate its role as the molecular entity of the intestinal folate transport system.

Region-dependent disappearance of vinblastine in rat small intestine and characterization of its P-glycoprotein-mediated efflux system

2000 ◽  
Vol 11 (4) ◽  
pp. 317-324 ◽  
Author(s):  
Akira Nakayama ◽  
Hiroshi Saitoh ◽  
Masako Oda ◽  
Masahiko Takada ◽  
Bruce J Aungst
Keyword(s):  
Small Intestine ◽  
Rat Small Intestine ◽  
Efflux System ◽  
P Glycoprotein

scholarly journals Functional Characterization of the Oxantel-Sensitive Acetylcholine Receptor from Trichuris muris

2021 ◽  
Vol 14 (7) ◽  
pp. 698
Author(s):  
Tina V. A. Hansen ◽  
Richard K. Grencis ◽  
Mohamed Issouf ◽  
Cédric Neveu ◽  
Claude L. Charvet
Keyword(s):  
Single Dose ◽  
Mouse Model ◽  
Xenopus Laevis ◽  
Acetylcholine Receptor ◽  
Drug Target ◽  
Functional Characterization ◽  
Xenopus Laevis Oocytes ◽  
Trichuris Muris ◽  
Electrode Voltage

The human whipworm, Trichuris trichiura, is estimated to infect 289.6 million people globally. Control of human trichuriasis is a particular challenge, as most anthelmintics have a limited single-dose efficacy, with the striking exception of the narrow-spectrum anthelmintic, oxantel. We recently identified a novel ACR-16-like subunit from the pig whipworm, T. suis which gave rise to a functional acetylcholine receptor (nAChR) preferentially activated by oxantel. However, there is no ion channel described in the mouse model parasite T. muris so far. Here, we have identified the ACR-16-like and ACR-19 subunits from T. muris, and performed the functional characterization of the receptors in Xenopus laevis oocytes using two-electrode voltage-clamp electrophysiology. We found that the ACR-16-like subunit from T. muris formed a homomeric receptor gated by acetylcholine whereas the ACR-19 failed to create a functional channel. The subsequent pharmacological analysis of the Tmu-ACR-16-like receptor revealed that acetylcholine and oxantel were equally potent. The Tmu-ACR-16-like was more responsive to the toxic agonist epibatidine, but insensitive to pyrantel, in contrast to the Tsu-ACR-16-like receptor. These findings confirm that the ACR-16-like nAChR from Trichuris spp. is a preferential drug target for oxantel, and highlights the pharmacological difference between Trichuris species.

Sequence, tissue distribution, and functional characterization of the rat fructose transporter GLUT5

1993 ◽  
Vol 264 (6) ◽  
pp. G1169-G1176 ◽  
Author(s):  
E. B. Rand ◽  
A. M. Depaoli ◽  
N. O. Davidson ◽  
G. I. Bell ◽  
C. F. Burant
Keyword(s):  
Small Intestine ◽  
Functional Characterization ◽  
Cdna Probe ◽  
Amino Acid Identity ◽  
Human Testis ◽  
Cdna Clones ◽  
Rat Tissues ◽  
Rat Small Intestine ◽  
Cross Hybridization ◽  
Distal Small Intestine

cDNA clones encoding rat GLUT5-small intestinal facilitative hexose transporter were isolated from a jejunum library by cross-hybridization with a human GLUT5 cDNA probe. The cDNA sequence indicates that rat GLUT5 is composed of 502 amino acids and has 81.5% amino acid identity and 87.3% similarity with the sequence of human GLUT5. Expression of synthetic rat GLUT5 mRNA in Xenopus oocytes showed that rat GLUT5 was able to mediate the uptake of fructose and, to a lesser extent, of glucose. RNA blotting studies showed that GLUT5 mRNA was present in rat small intestine, kidney, and brain. Although GLUT5 mRNA is expressed in human testis, adipose tissue, and skeletal muscle, it could not be detected by RNA blotting in these rat tissues. Developmental studies showed low levels of GLUT5 mRNA in rat small intestine and kidney during the prenatal period with a rapid induction of GLUT5 expression occurring postnatally. In situ hybridization studies of GLUT5 mRNA expression in the small intestine revealed differential expression along the crypt-villus axis with the highest levels of mRNA being in the midvillus region. In addition, there was quantitatively more GLUT5 mRNA detected in the proximal as opposed to the distal small intestine.

scholarly journals Functional Characterization of a High-Affinity Choline Transport System in Human Keratinocytes

2002 ◽  
Vol 119 (1) ◽  
pp. 118-121 ◽  
Author(s):  
Kathrin Hoffmann ◽  
Franziska Grafe ◽  
Wolfgang Wohlrab ◽  
Reinhard H. Neubert ◽  
Matthias Brandsch
Keyword(s):  
Transport System ◽  
Functional Characterization ◽  
Human Keratinocytes ◽  
Choline Transport ◽  
High Affinity

scholarly journals Characterization of aminocephalosporin transport across rat small intestine.

1983 ◽  
Vol 6 (4) ◽  
pp. 246-253 ◽  
Author(s):  
TOSHIKIRO KIMURA ◽  
TAKAO YAMAMOTO ◽  
MASAYUKI MIZUNO ◽  
YOSHIE SUGA ◽  
SUMIKO KITADE ◽  
...  
Keyword(s):  
Small Intestine ◽  
Rat Small Intestine

Functional characterization of leucine transport induced in Xenopus laevis oocytes injected with mRNA isolated from midguts of lepidopteran larvae (Philosamia cynthia).

1995 ◽  
Vol 198 (4) ◽  
pp. 961-966
Author(s):  
V F Sacchi ◽  
C Perego ◽  
S Magagnin
Keyword(s):  
Xenopus Laevis ◽  
Functional Characterization ◽  
Xenopus Laevis Oocytes ◽  
Fourfold Increase ◽  
Leucine Uptake ◽  
Lepidopteran Larvae ◽  
Nacl Concentration ◽  
Leucine Transport ◽  
The Difference

The injection of poly(A)+ mRNA prepared from Philosamia cynthia midgut caused time- and dose-dependent increases of leucine transport in Xenopus laevis oocytes, with an increase in leucine uptake 1.5-3 times that of oocytes injected with water. When the NaCl concentration was reduced from 100 to 5 mmol l-1, the difference between mRNA- and water-injected oocytes was greater and a fourfold increase of L-leucine uptake was measured. D-Leucine (10 mmol l-1) completely inhibited the induced uptake of 0.1 mmol l-1 L-leucine. The newly expressed component of L-leucine uptake increased at alkaline pH and was abolished by incubation for 15 min with 15 mmol l-1 phenylglyoxal. The mean Km values, calculated using Na+ activation curves of leucine uptake, were 23.3 +/- 6.1 mmol l-1 in water-injected oocytes and 0.4 +/- 0.2 mmol l-1 for the newly expressed component of leucine uptake in mRNA-injected oocytes. On the basis of these results, we conclude that the increase of L-leucine uptake in mRNA-injected oocytes was due to the expression of a new transport system, which differs from the endogenous ones and shares many features with that found previously in Philosamia cynthia midgut.

Cloning and functional characterization of a new subtype of the amino acid transport system N

2001 ◽  
Vol 281 (6) ◽  
pp. C1757-C1768 ◽  
Author(s):  
Takeo Nakanishi ◽  
Ramesh Kekuda ◽  
You-Jun Fei ◽  
Takahiro Hatanaka ◽  
Mitsuru Sugawara ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Transport System ◽  
Amino Acid Transport ◽  
Mammalian Cells ◽  
Functional Characterization ◽  
Isobutyric Acid ◽  
Xenopus Laevis Oocytes ◽  
Acid Transport ◽  
Amino Acid Transport System

We have cloned a new subtype of the amino acid transport system N2 (SN2 or second subtype of system N) from rat brain. Rat SN2 consists of 471 amino acids and belongs to the recently identified glutamine transporter gene family that consists of system N and system A. Rat SN2 exhibits 63% identity with rat SN1. It also shows considerable sequence identity (50–56%) with the members of the amino acid transporter A subfamily. In the rat, SN2 mRNA is most abundant in the liver but is detectable in the brain, lung, stomach, kidney, testis, and spleen. When expressed in Xenopus laevis oocytes and in mammalian cells, rat SN2 mediates Na+-dependent transport of several neutral amino acids, including glycine, asparagine, alanine, serine, glutamine, and histidine. The transport process is electrogenic, Li+tolerant, and pH sensitive. The transport mechanism involves the influx of Na+ and amino acids coupled to the efflux of H+, resulting in intracellular alkalization. Proline, α-(methylamino)isobutyric acid, and anionic and cationic amino acids are not recognized by rat SN2.

S20.9 An insoluble mucin complex from rat small intestine ? Characterization of two different glycosylated domains

1993 ◽  
Vol 10 (4) ◽  
pp. 344-344 ◽  
Author(s):  
I. Carlstedt ◽  
A. Herrmann ◽  
H. Karlsson ◽  
J. K. Sheehan ◽  
L. -A. Fransson ◽  
...  
Keyword(s):  
Small Intestine ◽  
Rat Small Intestine
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