Component

Human imino-acid transporter / SLC6A20

Context-specific entity; species, compartment and exposure are stated on each claim.

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. SLC6A20 mutations accompanied iminoglycinuria when combined with SLC36A2 variants retaining residual transport.

    Human imino-acid transporter / SLC6A20 → Phenotype with residual SLC36A2 transport source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary abstract
    experimental_model
    Human family genotype/functional analysis.
    limitations
    Modifier evidence is not proof of ordinary dietary competition between glycine and proline.
    nutrient_topic
    Glycine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · Glycine
    plain_language
    A second transporter can change the effect of the first defect.
    primary_references
    Iminoglycinuria and hyperglycinuria are discrete human phenotypes resulting from complex mutations in proline and glycine transporters. · 2008 · https://pubmed.ncbi.nlm.nih.gov/19033659/ · DOI 10.1172/JCI36625
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    Glycine: supply, one-carbon allocation, receptors and cross-nutrient mechanisms (2026-09-19) · lines 74–80

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human family genotype/functional analysis. · source_derived_draft · unverified_draft

    ## glycine-renal-modifier A second transporter can change the effect of the first defect. SLC6A20 mutations accompanied iminoglycinuria when combined with SLC36A2 variants retaining residual transport. Model: Human family genotype/functional analysis. Limitations: Modifier evidence is not proof of ordinary dietary competition between glycine and proline. Evidence access: Primary abstract Iminoglycinuria and hyperglycinuria are discrete human phenotypes resulting from complex mutations in proline and glycine transporters. · 2008 · https://pubmed.ncbi.nlm.nih.gov/19033659/ · DOI 10.1172/JCI36625
    Complete structured claim and evidence

  2. Cryo-EM resolved human SIT1 in complex with ACE2, with pipecolate-bound and substrate-free conformations identifying the cytoplasmic gate and substrate-release changes.

    Human imino-acid transporter / SLC6A20 → Human angiotensin-converting enzyme 2 / ACE2 source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary full text
    experimental_model
    Purified human ACE2-SIT1 complex; pipecolate is a proline-related ligand, not proline itself.
    limitations
    ACE2 partnership does not establish that proline intake changes susceptibility to viral infection.
    nutrient_topic
    L-Proline collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Proline
    plain_language
    A transporter can use a partner protein and still have its own distinct transport mechanism.
    primary_references
    Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x

    L-Proline: synthesis, collagen processing, redox metabolism and cross-nutrient mechanisms (2026-09-19) · lines 182–188

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified human ACE2-SIT1 complex; pipecolate is a proline-related ligand, not proline itself. · source_derived_draft · unverified_draft

    ## l-proline-sit1-ace2 A transporter can use a partner protein and still have its own distinct transport mechanism. Cryo-EM resolved human SIT1 in complex with ACE2, with pipecolate-bound and substrate-free conformations identifying the cytoplasmic gate and substrate-release changes. Model: Purified human ACE2-SIT1 complex; pipecolate is a proline-related ligand, not proline itself. Limitations: ACE2 partnership does not establish that proline intake changes susceptibility to viral infection. Evidence access: Primary full text Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x
    Complete structured claim and evidence

  3. Human SIT1 produced glycine-evoked current about 18% of the proline response in the reported substrate comparison; sarcosine current was about 83%.

    Human imino-acid transporter / SLC6A20 → Glycine source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary full text
    experimental_model
    Human SIT1 in Xenopus oocytes; 1 mM substrates at pH 7.4 and -60 mV.
    limitations
    Failure of glycine to stabilize purified SIT1 thermally did not rule out its transport; binding-proxy and transport assays measure different things.
    nutrient_topic
    L-Proline collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Proline
    plain_language
    This transporter has overlapping amino-acid routes with unequal efficiency.
    primary_references
    Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x

    L-Proline: synthesis, collagen processing, redox metabolism and cross-nutrient mechanisms (2026-09-19) · lines 190–196

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human SIT1 in Xenopus oocytes; 1 mM substrates at pH 7.4 and -60 mV. · source_derived_draft · unverified_draft

    ## l-proline-sit1-glycine This transporter has overlapping amino-acid routes with unequal efficiency. Human SIT1 produced glycine-evoked current about 18% of the proline response in the reported substrate comparison; sarcosine current was about 83%. Model: Human SIT1 in Xenopus oocytes; 1 mM substrates at pH 7.4 and -60 mV. Limitations: Failure of glycine to stabilize purified SIT1 thermally did not rule out its transport; binding-proxy and transport assays measure different things. Evidence access: Primary full text Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x
    Complete structured claim and evidence

  4. Human SIT1/SLC6A20 functioned as a sodium-dependent proline transporter when expressed for functional testing.

    Human imino-acid transporter / SLC6A20 → L-Proline source_derived_draftungraded
    Experimental context and source evidence
    evidence_access
    Primary abstract
    experimental_model
    Human SIT1 heterologous expression in the mammalian transporter identification study.
    limitations
    Rat concentration-response and ion-substitution details are recorded separately rather than assumed identical in humans.
    nutrient_topic
    L-Proline collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Proline
    plain_language
    Cell entry depends on transport machinery and ion gradients.
    primary_references
    Identification of mammalian proline transporter SIT1 (SLC6A20) with characteristics of classical system imino. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15632147/ · DOI 10.1074/jbc.M413027200
    transport_effect
    raises Functioned as a sodium-dependent proline transporter, which is inward.
    transport_pool
    the expressing cell Functioned as a sodium-dependent proline transporter, which is inward.

    L-Proline: synthesis, collagen processing, redox metabolism and cross-nutrient mechanisms (2026-09-19) · lines 166–172

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human SIT1 heterologous expression in the mammalian transporter identification study. · source_derived_draft · unverified_draft

    ## l-proline-sit1-uptake Cell entry depends on transport machinery and ion gradients. Human SIT1/SLC6A20 functioned as a sodium-dependent proline transporter when expressed for functional testing. Model: Human SIT1 heterologous expression in the mammalian transporter identification study. Limitations: Rat concentration-response and ion-substitution details are recorded separately rather than assumed identical in humans. Evidence access: Primary abstract Identification of mammalian proline transporter SIT1 (SLC6A20) with characteristics of classical system imino. · 2005 · https://pubmed.ncbi.nlm.nih.gov/15632147/ · DOI 10.1074/jbc.M413027200
    Complete structured claim and evidence

  5. SIT1 T199M reduced maximal proline-induced transport current about threefold, supporting a defect in gate dynamics implicated in iminoglycinuria.

    Human imino-acid transporter / SLC6A20 → Human SIT1 T199M proline transport capacity source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    machinery_impairment Imported condition classification; unverified.
    evidence_access
    Primary full text
    experimental_model
    Human SIT1 variant expressed in Xenopus oocytes with structural interpretation.
    limitations
    The proposed packing mechanism is an interpretation informed by structure, while reduced current was measured.
    nutrient_topic
    L-Proline collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Proline
    plain_language
    A transporter can reach the assay system yet move substrate less efficiently.
    primary_references
    Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x
    trigger_kind
    machinery_impairment Imported condition classification; unverified.

    L-Proline: synthesis, collagen processing, redox metabolism and cross-nutrient mechanisms (2026-09-19) · lines 198–204

    AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human SIT1 variant expressed in Xenopus oocytes with structural interpretation. · source_derived_draft · unverified_draft

    ## l-proline-sit1-variant A transporter can reach the assay system yet move substrate less efficiently. SIT1 T199M reduced maximal proline-induced transport current about threefold, supporting a defect in gate dynamics implicated in iminoglycinuria. Model: Human SIT1 variant expressed in Xenopus oocytes with structural interpretation. Limitations: The proposed packing mechanism is an interpretation informed by structure, while reduced current was measured. Evidence access: Primary full text Structure and function of the SIT1 proline transporter in complex with the COVID-19 receptor ACE2. · 2024 · https://pubmed.ncbi.nlm.nih.gov/38951531/ · DOI 10.1038/s41467-024-48921-x
    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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