Evidence map›Paper›PMID 17962486›Full record

ArticleInvestigative ophthalmology & visual science2007

Cloning and functional characterization of the proton-coupled electrogenic folate transporter and analysis of its expression in retinal cell types.

Nagavedi S Umapathy, Jaya P Gnana-Prakasam, Pamela M Martin, Barbara Mysona, Ying Dun, Sylvia B Smith, Vadivel Ganapathy, Puttur D Prasad

Open access · greenAbstract read
In one paragraph

Article in Investigative ophthalmology & visual science, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 34 papers.

0numbers the graph read from it
0cells of the map it votes in
34citing papers in PubMed
3.2field-weighted citation impact, top 9% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

34 citing papers in PubMed, 60 citations in OpenAlex.

  1. Review
  2. The evolving biology of the proton-coupled folate transporter: New insights into regulation, structure, and mechanism.FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2022
    Review
  3. Article
  4. Folic acid deficiency and vision: a review.Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie · 2019
    Review
  5. Roles of Drug Transporters in Blood-Retinal Barrier.Advances in experimental medicine and biology · 2019
    Review
  6. Article
  7. Article
  8. Review
  9. Article
  10. Article
  11. Article
  12. Article
  13. Article
  14. Review
  15. Review
  16. The intestinal absorption of folates.Annual review of physiology · 2014
    Review
  17. Article
  18. Review
  19. Article
  20. Prodrug strategies in ocular drug delivery.Medicinal chemistry (Shariqah (United Arab Emirates)) · 2012
    Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors at 1 institution in 1 country.

Nagavedi S UmapathyDepartment of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, GA 30912, USA.
Jaya P Gnana-Prakasam
Pamela M Martin
Barbara Mysona
Ying Dun
Sylvia B Smith
Vadivel Ganapathy
Puttur D Prasad
Augusta University · US

Funding

Role of homocysteine in retinal diseaseR01EY012830 · NEI · MEDICAL COLLEGE OF GEORGIA (MCG) · PI SMITH, SYLVIA B. · 2000 to 2016
$4.4M
NEI NIH HHS EY012830NEI NIH HHS R01 EY012830
6 · The paper itself

Abstract

purposeIn a prior study the cellular uptake of folate was investigated in the retina. Recently, a new proton-coupled folate transporter (PCFT) in human intestine was reported. In the present study, the expression of this novel transporter in the retina was determined, the mouse orthologue was cloned from retinal tissue, and its transport function was characterized.

methodsRT-PCR and folate uptake measurements were used to detect the expression of PCFT in mouse retina and in retinal cell types. The expression of PCFT mRNA in intact retina was investigated by in situ hybridization. Mouse PCFT cDNA was cloned, and its transport characteristics were analyzed by electrophysiological methods after expression of the cloned transporter in Xenopus laevis oocytes.

resultsRT-PCR showed expression of PCFT mRNA in both neural retina and RPE eye cup. In situ hybridization detected PCFT mRNA in all retinal cell layers. Proton-coupled folate uptake was detectable in primary cultures of ganglion, Müller, and RPE cells of mouse retina and in RPE, ganglion, and Müller cells of human or rat origin. In X. laevis oocytes expressing the cloned mouse PCFT, folate and its derivatives methotrexate and 5-methyltetrahydrofolate induced H(+)-coupled inward currents with K(t) values of 1.2 +/- 0.1, 4.6 +/- 0.5, and 3.5 +/- 0.8 microM, respectively. The transport process showed an H(+)-folate stoichiometry of 1:1, suggesting that PCFT transports the zwitterionic form of folate.

conclusionsThis is the first report on the expression of PCFT in the retina. All cell layers of the retina express this transporter. Mouse PCFT, cloned from retina, mediates H(+)-coupled electrogenic transport of folate and its derivatives.

Indexed as

AnimalsCell LineCloning, MolecularFemaleFolic AcidGene ExpressionHumansIn Situ HybridizationMembrane Transport ProteinsMethotrexateMiceMice, Inbred BALB CMice, Inbred C57BLNeurogliaOocytesPigment Epithelium of Eye5-methyltetrahydrofolateFolic AcidMembrane Transport ProteinsMethotrexateProton-Coupled Folate TransporterRNA, MessengerSlc46a1 protein, mouseTetrahydrofolates

Identifiers

PMID17962486
PMCPMC3850295
OpenAlexW1977466251

What OpenQuestion holds

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Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.