Component

Riboflavin transporter 3 / SLC52A3

Human RFVT3; older papers call this hRFT2 or C20orf54.

5 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Lowering extracellular pH from 7.5 to 5.5 increased RFVT3-mediated riboflavin uptake and changed its apparent kinetic parameters.

    Riboflavin transporter 3 / SLC52A3 → Riboflavin (vitamin B2) source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Figure 1c-e
    experimental_model
    Human RFVT3 expression and stable-isotope uptake
    exposure
    pH 5.5 versus 7.5; concentration-dependent [13C]riboflavin uptake.
    limitations
    In vitro pH comparison; not advice to alter gastrointestinal acidity.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens
    plain_language
    Acidic conditions enhanced RFVT3 transport in the experiment.
    primary_references
    [transport-rfvt-structure-2025] Structure and transport mechanism of human riboflavin transporters (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12044054/ DOI: 10.1038/s41467-025-59255-7
    tissue_or_cell_type
    HEK293T cells
    transport_effect
    raises Lowering extracellular pH increased RFVT3-mediated riboflavin uptake.
    transport_pool
    the expressing cell Lowering extracellular pH increased RFVT3-mediated riboflavin uptake.

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 241–252

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human RFVT3 expression and stable-isotope uptake · source_derived_draft · unverified_draft

    ### transport-rfvt3-low-ph Lowering extracellular pH from 7.5 to 5.5 increased RFVT3-mediated riboflavin uptake and changed its apparent kinetic parameters. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Acidic conditions enhanced RFVT3 transport in the experiment. organism: Homo sapiens tissue_or_cell_type: HEK293T cells experimental_model: Human RFVT3 expression and stable-isotope uptake limitations: In vitro pH comparison; not advice to alter gastrointestinal acidity. exposure: pH 5.5 versus 7.5; concentration-dependent [13C]riboflavin uptake. evidence_location: Figure 1c-e [transport-rfvt-structure-2025] Structure and transport mechanism of human riboflavin transporters (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12044054/ DOI: 10.1038/s41467-025-59255-7
    Complete structured claim and evidence

  2. Purified RFVT3 proteoliposomes showed riboflavin-associated proton influx; D119/E145 mutagenesis identified determinants of pH-sensitive transport.

    Riboflavin transporter 3 / SLC52A3 → Cellular riboflavin uptake source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Figure 4g-l and discussion
    experimental_model
    Purified human transporter proteoliposomes and mutagenesis
    exposure
    Riboflavin addition with proton-sensitive 9-aminoacridine readout.
    limitations
    Proton/riboflavin stoichiometry and exact residue-specific transport steps remain unresolved.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens protein in reconstituted membranes
    plain_language
    RFVT3 can connect riboflavin transport with proton movement.
    primary_references
    [transport-rfvt-structure-2025] Structure and transport mechanism of human riboflavin transporters (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12044054/ DOI: 10.1038/s41467-025-59255-7
    tissue_or_cell_type
    Cell-free proteoliposomes

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 254–265

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human transporter proteoliposomes and mutagenesis · source_derived_draft · unverified_draft

    ### transport-rfvt3-proton-coupling Purified RFVT3 proteoliposomes showed riboflavin-associated proton influx; D119/E145 mutagenesis identified determinants of pH-sensitive transport. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: RFVT3 can connect riboflavin transport with proton movement. organism: Homo sapiens protein in reconstituted membranes tissue_or_cell_type: Cell-free proteoliposomes experimental_model: Purified human transporter proteoliposomes and mutagenesis limitations: Proton/riboflavin stoichiometry and exact residue-specific transport steps remain unresolved. exposure: Riboflavin addition with proton-sensitive 9-aminoacridine readout. evidence_location: Figure 4g-l and discussion [transport-rfvt-structure-2025] Structure and transport mechanism of human riboflavin transporters (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12044054/ DOI: 10.1038/s41467-025-59255-7
    Complete structured claim and evidence

  3. RFVT3-directed siRNA decreased apical radiolabeled-riboflavin uptake by human T84 epithelial cells.

    Riboflavin transporter 3 / SLC52A3 → Intestinal riboflavin uptake source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_location
    RFVT3 siRNA experiment
    experimental_model
    T84 siRNA and apical tracer-uptake assay
    exposure
    RFVT3-specific siRNA compared with control siRNA.
    limitations
    Partial gene silencing in cultured cells; other uptake routes remain possible.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens
    plain_language
    Reducing RFVT3 lowers intestinal-cell riboflavin uptake.
    primary_references
    [transport-rfvt3-2014] Functional involvement of RFVT3/SLC52A3 in intestinal riboflavin absorption. (2014). https://doi.org/10.1152/ajpgi.00349.2013 DOI: 10.1152/ajpgi.00349.2013
    tissue_or_cell_type
    Intestinal epithelial T84 cells
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 215–226

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · T84 siRNA and apical tracer-uptake assay · source_derived_draft · unverified_draft

    ### transport-rfvt3-silencing RFVT3-directed siRNA decreased apical radiolabeled-riboflavin uptake by human T84 epithelial cells. Condition category: machinery_impairment nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Reducing RFVT3 lowers intestinal-cell riboflavin uptake. organism: Homo sapiens tissue_or_cell_type: Intestinal epithelial T84 cells experimental_model: T84 siRNA and apical tracer-uptake assay limitations: Partial gene silencing in cultured cells; other uptake routes remain possible. exposure: RFVT3-specific siRNA compared with control siRNA. evidence_location: RFVT3 siRNA experiment [transport-rfvt3-2014] Functional involvement of RFVT3/SLC52A3 in intestinal riboflavin absorption. (2014). https://doi.org/10.1152/ajpgi.00349.2013 DOI: 10.1152/ajpgi.00349.2013
    Complete structured claim and evidence

  4. RFVT3-expressing HEK293 cells transported riboflavin strongly, FMN weakly, and showed no measurable FAD transport in the reported assay.

    Riboflavin transporter 3 / SLC52A3 → Riboflavin (vitamin B2) source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Figure 3C-E
    experimental_model
    HEK293 expression; HPLC measurement of flavin uptake
    exposure
    10 micromolar flavin, pH 7.4, 10 minutes, 37 C.
    limitations
    Substrate preference under these conditions is not proof of zero FMN transport at every concentration.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Homo sapiens
    plain_language
    Free riboflavin was the preferred transported flavin.
    primary_references
    [transport-rfvt3-2014] Functional involvement of RFVT3/SLC52A3 in intestinal riboflavin absorption. (2014). https://doi.org/10.1152/ajpgi.00349.2013 DOI: 10.1152/ajpgi.00349.2013
    tissue_or_cell_type
    HEK293 cells

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 228–239

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · HEK293 expression; HPLC measurement of flavin uptake · source_derived_draft · unverified_draft

    ### transport-rfvt3-substrate-discrimination RFVT3-expressing HEK293 cells transported riboflavin strongly, FMN weakly, and showed no measurable FAD transport in the reported assay. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Free riboflavin was the preferred transported flavin. organism: Homo sapiens tissue_or_cell_type: HEK293 cells experimental_model: HEK293 expression; HPLC measurement of flavin uptake limitations: Substrate preference under these conditions is not proof of zero FMN transport at every concentration. exposure: 10 micromolar flavin, pH 7.4, 10 minutes, 37 C. evidence_location: Figure 3C-E [transport-rfvt3-2014] Functional involvement of RFVT3/SLC52A3 in intestinal riboflavin absorption. (2014). https://doi.org/10.1152/ajpgi.00349.2013 DOI: 10.1152/ajpgi.00349.2013
    Complete structured claim and evidence

  5. Tagged human Riboflavin transporter 3 / SLC52A3 localized at the apical membrane in polarized Caco-2 and MDCK imaging experiments.

    Riboflavin transporter 3 / SLC52A3 → Intestinal epithelial apical membrane source_derived_draftungraded
    Experimental context and source evidence
    evidence_location
    Live-cell imaging; historical RFT1/2/3 correspond to RFVT1/3/2
    experimental_model
    Live-cell confocal imaging of tagged transporter constructs
    exposure
    Expression of fluorescent transporter constructs.
    limitations
    Tagged overexpression in epithelial models; not a universal localization map across tissues.
    nutrient_topic
    Riboflavin research collection; topical membership is not evidence of a direct dietary effect. · Riboflavin (vitamin B2)
    organism
    Human proteins in human and canine cells
    plain_language
    The riboflavin transporters occupy different parts of polarized epithelial cells.
    primary_references
    [transport-localization-2011] Differential expression of human riboflavin transporters -1, -2, and -3 in polarized epithelia: a key role for hRFT-2 in intestinal riboflavin uptake. (2011). https://pubmed.ncbi.nlm.nih.gov/21854757/ DOI: 10.1016/j.bbamem.2011.08.004
    tissue_or_cell_type
    Polarized Caco-2 and MDCK cells

    Riboflavin: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 202–213

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Live-cell confocal imaging of tagged transporter constructs · source_derived_draft · unverified_draft

    ### transport-slc52a3-localization Tagged human Riboflavin transporter 3 / SLC52A3 localized at the apical membrane in polarized Caco-2 and MDCK imaging experiments. Condition category: normal nutrient_topic: Riboflavin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The riboflavin transporters occupy different parts of polarized epithelial cells. organism: Human proteins in human and canine cells tissue_or_cell_type: Polarized Caco-2 and MDCK cells experimental_model: Live-cell confocal imaging of tagged transporter constructs limitations: Tagged overexpression in epithelial models; not a universal localization map across tissues. exposure: Expression of fluorescent transporter constructs. evidence_location: Live-cell imaging; historical RFT1/2/3 correspond to RFVT1/3/2 [transport-localization-2011] Differential expression of human riboflavin transporters -1, -2, and -3 in polarized epithelia: a key role for hRFT-2 in intestinal riboflavin uptake. (2011). https://pubmed.ncbi.nlm.nih.gov/21854757/ DOI: 10.1016/j.bbamem.2011.08.004
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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