Component
Guanosine diphosphate
GDP nucleotide associated with inactive heterotrimeric G protein alpha subunits.
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.
Where it participates (unsigned role)
Reconstituted G-protein assays supported Mg-dependent restraint of Galpha nucleotide exchange; reduced Mg enhanced signaling associated with basal CaSR activity.
Experimental context and source evidence
- availability_state
- nutrient_deficiency Imported condition classification; unverified.
- cross_nutrient
- magnesium -> CaSR/PTH -> calcium
- experimental_model
- CaSR-expressing HEK-293 membranes reconstituted with G proteins
- limitations
- Mechanistic explanation supported by probes; not an established sole cause of human hypomagnesemic hypocalcemia.
- nutrient_topic
- Magnesium research collection; topical membership is not evidence of a direct dietary effect. · Magnesium
- organism
- Human receptor-expression system with purified/recombinant G proteins
- plain_language
- Less Mg can loosen the restraint on the G-protein switch, allowing the receptor pathway to suppress PTH more strongly.
- primary_references
- [quitterer-2001-magnesium-paradox] Paradoxical block of parathormone secretion is mediated by increased activity of G alpha subunits (2001). https://pubmed.ncbi.nlm.nih.gov/11102444/ DOI: 10.1074/jbc.M007727200
- tissue_or_cell_type
- Reconstituted membrane signaling system
- trigger_kind
- nutrient_deficiency Imported condition classification; unverified.
Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17) · lines 457–467
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · CaSR-expressing HEK-293 membranes reconstituted with G proteins · source_derived_draft · unverified_draft
### low-mg-galpha-exchange-explains-paradox Reconstituted G-protein assays supported Mg-dependent restraint of Galpha nucleotide exchange; reduced Mg enhanced signaling associated with basal CaSR activity. Condition category: nutrient_deficiency nutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Less Mg can loosen the restraint on the G-protein switch, allowing the receptor pathway to suppress PTH more strongly. organism: Human receptor-expression system with purified/recombinant G proteins tissue_or_cell_type: Reconstituted membrane signaling system experimental_model: CaSR-expressing HEK-293 membranes reconstituted with G proteins limitations: Mechanistic explanation supported by probes; not an established sole cause of human hypomagnesemic hypocalcemia. cross_nutrient: magnesium -> CaSR/PTH -> calcium [quitterer-2001-magnesium-paradox] Paradoxical block of parathormone secretion is mediated by increased activity of G alpha subunits (2001). https://pubmed.ncbi.nlm.nih.gov/11102444/ DOI: 10.1074/jbc.M007727200
Complete structured claim and evidencePurified human MMAA displayed intrinsic GTPase activity modulated by human MMUT.
Experimental context and source evidence
- cross_nutrient
- false
- evidence_location
- Indexed primary abstract; indexed Results
- experimental_model
- Purified human proteins
- exposure
- GTP hydrolysis assay
- limitations
- Biochemical reconstitution; does not determine cellular rate or dietary requirement.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Human MMAA consumed GTP in the protein assay, linking energy use to B12 handling.
- primary_references
- [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
- tissue_or_cell_type
- Purified protein assay
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1033–1045
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified human proteins · source_derived_draft · unverified_draft
### mmaa-hydrolyzes-gtp Purified human MMAA displayed intrinsic GTPase activity modulated by human MMUT. Condition category: normal nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Human MMAA consumed GTP in the protein assay, linking energy use to B12 handling. organism: Homo sapiens tissue_or_cell_type: Purified protein assay experimental_model: Purified human proteins limitations: Biochemical reconstitution; does not determine cellular rate or dietary requirement. exposure: GTP hydrolysis assay cross_nutrient: false evidence_location: Indexed primary abstract; indexed Results [froese-2010-human-mmaa] Structures of the human GTPase MMAA and vitamin B12-dependent methylmalonyl-CoA mutase and insight into their complex formation. (2010). https://pubmed.ncbi.nlm.nih.gov/20876572/ DOI: 10.1074/jbc.m110.177717
Complete structured claim and evidencePhotoactivated rhodopsin catalyzed GDP-to-GTP nucleotide exchange on transducin in reconstituted bovine rod preparations.
Experimental context and source evidence
- experimental_model
- Purified protein reconstitution
- limitations
- Biochemical amplification is not a nutritional dose response.
- nutrient_topic
- Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A
- organism
- Bos taurus
- plain_language
- Activated pigment switches transducin into its signaling state.
- primary_references
- [fung-1981] Flow of information in the light-triggered cyclic nucleotide cascade of vision (1981). https://pubmed.ncbi.nlm.nih.gov/6264430/ DOI: 10.1073/pnas.78.1.152
- tissue_or_cell_type
- Rod outer-segment protein system
Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 905–914
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purified protein reconstitution · source_derived_draft · unverified_draft
### a-vision-transducin-exchange Photoactivated rhodopsin catalyzed GDP-to-GTP nucleotide exchange on transducin in reconstituted bovine rod preparations. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: Activated pigment switches transducin into its signaling state. organism: Bos taurus tissue_or_cell_type: Rod outer-segment protein system experimental_model: Purified protein reconstitution limitations: Biochemical amplification is not a nutritional dose response. [fung-1981] Flow of information in the light-triggered cyclic nucleotide cascade of vision (1981). https://pubmed.ncbi.nlm.nih.gov/6264430/ DOI: 10.1073/pnas.78.1.152
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.