Component
Human cubilin-amnionless complex
Human CUBN-AMN receptor complex; ligand recognition and membrane anchorage are separate functions.
3 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
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.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
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.
What acts on it
Human renal cubilin and AMN remained associated during coelution in EDTA, indicating that their mutual association did not require calcium under these conditions.
Experimental context and source evidence
- cross_nutrient
- true
- experimental_model
- Human kidney cubilin-AMN purification with chelation
- exposure
- EDTA present during coelution
- limitations
- Chelation result concerns CUBN-AMN association, not IF-cobalamin docking or whole-body calcium deficiency.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Calcium dependence concerns ligand binding, not every receptor interaction.
- primary_references
- [fyfe-2004-cubam] The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless. (2004). https://pubmed.ncbi.nlm.nih.gov/14576052/ DOI: 10.1182/blood-2003-08-2852
- tissue_or_cell_type
- Renal epithelial receptor complex
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 231–242
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human kidney cubilin-AMN purification with chelation · source_derived_draft · unverified_draft
### b12-abs-cubam-association-calcium Human renal cubilin and AMN remained associated during coelution in EDTA, indicating that their mutual association did not require calcium under these conditions. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Calcium dependence concerns ligand binding, not every receptor interaction. organism: Homo sapiens tissue_or_cell_type: Renal epithelial receptor complex experimental_model: Human kidney cubilin-AMN purification with chelation limitations: Chelation result concerns CUBN-AMN association, not IF-cobalamin docking or whole-body calcium deficiency. exposure: EDTA present during coelution cross_nutrient: true [fyfe-2004-cubam] The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless. (2004). https://pubmed.ncbi.nlm.nih.gov/14576052/ DOI: 10.1182/blood-2003-08-2852
Complete structured claim and evidence
Where it participates (unsigned role)
Human renal cubilin and AMN copurified and coeluted as a tightly associated complex that required denaturing conditions for separation.
Experimental context and source evidence
- cross_nutrient
- false
- experimental_model
- Affinity purification and gel filtration of human kidney membrane proteins
- exposure
- IF-cobalamin affinity chromatography; nondenaturing versus denaturing separation
- limitations
- Native renal purification establishes association; intestinal uptake rate is not measured by this experiment.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Cubilin and amnionless form a stable receptor pair.
- primary_references
- [fyfe-2004-cubam] The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless. (2004). https://pubmed.ncbi.nlm.nih.gov/14576052/ DOI: 10.1182/blood-2003-08-2852
- tissue_or_cell_type
- Renal epithelial membranes
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 218–229
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Affinity purification and gel filtration of human kidney membrane proteins · source_derived_draft · unverified_draft
### b12-abs-cubam-association Human renal cubilin and AMN copurified and coeluted as a tightly associated complex that required denaturing conditions for separation. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Cubilin and amnionless form a stable receptor pair. organism: Homo sapiens tissue_or_cell_type: Renal epithelial membranes experimental_model: Affinity purification and gel filtration of human kidney membrane proteins limitations: Native renal purification establishes association; intestinal uptake rate is not measured by this experiment. exposure: IF-cobalamin affinity chromatography; nondenaturing versus denaturing separation cross_nutrient: false [fyfe-2004-cubam] The functional cobalamin (vitamin B12)-intrinsic factor receptor is a novel complex of cubilin and amnionless. (2004). https://pubmed.ncbi.nlm.nih.gov/14576052/ DOI: 10.1182/blood-2003-08-2852
Complete structured claim and evidenceThe authors attributed diminished B12 absorption and low serum B12 and transcobalamin-bound B12 during metformin to a calcium-dependent ileal membrane antagonism, since uptake of the B12-intrinsic factor complex by ileal cell surface receptors is calcium-dependent.
Experimental context and source evidence
- availability_state
- nutrient_deficiency Imported condition classification; unverified.
- evidence_span
- {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"}
- experimental_model
- Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation
- exposure
- Metformin for three months, then oral calcium supplementation
- limitations
- A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding.
- nutrient_topic
- Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. · Metformin
- organism
- Human
- plain_language
- The proposed step is the calcium-dependent grab of the vitamin at the ileal cell surface.
- primary_references
- [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
- tissue_or_cell_type
- Ileal absorption
- trigger_kind
- nutrient_deficiency Imported condition classification; unverified.
Metformin: transport, molecular targets, gut mechanisms and nutrient interactions (2026-09-19) · lines 1152–1163
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation · source_derived_draft · unverified_draft
### metformin-b12-calcium-mechanism The authors attributed diminished B12 absorption and low serum B12 and transcobalamin-bound B12 during metformin to a calcium-dependent ileal membrane antagonism, since uptake of the B12-intrinsic factor complex by ileal cell surface receptors is calcium-dependent. Condition category: nutrient_deficiency nutrient_topic: Metformin research collection; topical membership is not evidence of a direct clinical effect, and pharmacological exposure is not dietary intake. plain_language: The proposed step is the calcium-dependent grab of the vitamin at the ileal cell surface. organism: Human tissue_or_cell_type: Ileal absorption experimental_model: Comparative study in 21 people with type 2 diabetes, 14 switched to metformin, with oral calcium supplementation limitations: A small, non-randomised comparative study. The calcium-dependent ileal mechanism is the authors’ interpretation of the reversal, not a direct measurement of receptor binding. exposure: Metformin for three months, then oral calcium supplementation evidence_span: {"source_cache": "artifacts/metformin-research/10977010.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b", "start_char": 0, "end_char": 1267, "text_sha256": "7aed1bfb7ee680b248e083db467fd4a8199ac933e8a12b4c6ba08f9931a7794b"} [metformin-p10977010] Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. (2000). https://pubmed.ncbi.nlm.nih.gov/10977010/ DOI: 10.2337/diacare.23.9.1227
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.