| RRC ID |
61152
|
| 著者 |
Inoue K, Nakai Y, Ueda S, Kamigaso S, Ohta KY, Hatakeyama M, Hayashi Y, Otagiri M, Yuasa H.
|
| タイトル |
Functional characterization of PCFT/HCP1 as the molecular entity of the carrier-mediated intestinal folate transport system in the rat model.
|
| ジャーナル |
Am J Physiol Gastrointest Liver Physiol
|
| Abstract |
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 (K(m)) for the former (2.4 microM) than for the latter (5.7 microM), 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 K(m) values were 1.2 and 5.8 microM 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.
|
| 巻・号 |
294(3)
|
| ページ |
G660-8
|
| 公開日 |
2008-3-1
|
| DOI |
10.1152/ajpgi.00309.2007
|
| PII |
00309.2007
|
| PMID |
18174275
|
| MeSH |
Animals
Anion Transport Proteins / genetics
Anion Transport Proteins / physiology*
Biological Transport, Active
Blotting, Northern
DNA, Complementary / biosynthesis
DNA, Complementary / genetics
Data Interpretation, Statistical
Folic Acid / metabolism*
Folic Acid Antagonists / metabolism
Folic Acid Antagonists / pharmacology
Hydrogen-Ion Concentration
In Vitro Techniques
Intestinal Mucosa / metabolism*
Intestine, Small / drug effects
Intestine, Small / metabolism
Methotrexate / metabolism
Methotrexate / pharmacology
Oocytes
Proton-Coupled Folate Transporter
Rats
Reverse Transcriptase Polymerase Chain Reaction
Xenopus laevis
|
| IF |
3.725
|
| リソース情報 |
| 遺伝子材料 |
pCI-neo-rPCFT (RDB18231) |
