Component
Human phosphatidylserine synthase 1 / PTDSS1
Context-specific entity; species, compartment and exposure are stated on each claim.
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 it acts on
Purified human PSS1 reconstituted with phosphatidylcholine showed serine base-exchange activity producing phosphatidylserine.
Experimental context and source evidence
- evidence_access
- Primary full text
- experimental_model
- Human PSS1 proteoliposomes with POPC and radioactive serine assays.
- limitations
- The bound endogenous lipid density could not conclusively distinguish PC from PE; no universal exclusion of PE is asserted.
- nutrient_topic
- L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Serine
- plain_language
- Serine can replace a phospholipid headgroup to make a different membrane lipid.
- primary_references
- Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3
L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19) · lines 246–252
AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human PSS1 proteoliposomes with POPC and radioactive serine assays. · source_derived_draft · unverified_draft
## l-serine-pss1-exchange Serine can replace a phospholipid headgroup to make a different membrane lipid. Purified human PSS1 reconstituted with phosphatidylcholine showed serine base-exchange activity producing phosphatidylserine. Model: Human PSS1 proteoliposomes with POPC and radioactive serine assays. Limitations: The bound endogenous lipid density could not conclusively distinguish PC from PE; no universal exclusion of PE is asserted. Evidence access: Primary full text Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3
Complete structured claim and evidence
What acts on it
Human PSS1 structures positioned calcium and serine in the catalytic pocket; structural and mutational analysis implicated His172 in the base-exchange mechanism.
Experimental context and source evidence
- evidence_access
- Primary full text
- experimental_model
- Full-length human PSS1 cryo-EM in apo, calcium-bound and calcium/serine-bound states.
- limitations
- The proposed chemical mechanism combines structure and mutagenesis; it is not a clinical calcium-response experiment.
- nutrient_topic
- L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Serine
- plain_language
- Calcium has a constructive catalytic role in this lipid-building enzyme.
- primary_references
- Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3
L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19) · lines 254–260
AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Full-length human PSS1 cryo-EM in apo, calcium-bound and calcium/serine-bound states. · source_derived_draft · unverified_draft
## l-serine-pss1-calcium Calcium has a constructive catalytic role in this lipid-building enzyme. Human PSS1 structures positioned calcium and serine in the catalytic pocket; structural and mutational analysis implicated His172 in the base-exchange mechanism. Model: Full-length human PSS1 cryo-EM in apo, calcium-bound and calcium/serine-bound states. Limitations: The proposed chemical mechanism combines structure and mutagenesis; it is not a clinical calcium-response experiment. Evidence access: Primary full text Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3
Complete structured claim and evidencePTDSS1 variants from Lenz-Majewski syndrome markedly reduced product inhibition by phosphatidylserine and increased phosphatidylserine synthesis in patient fibroblasts.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- evidence_access
- Primary abstract
- experimental_model
- Human genetics and patient fibroblast synthesis assays.
- limitations
- These gain-of-function variants are not serine shortage or proof of an effect from phosphatidylserine supplements.
- nutrient_topic
- L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Serine
- plain_language
- Failure of a feedback brake can increase lipid production.
- primary_references
- Gain-of-function mutations in the phosphatidylserine synthase 1 (PTDSS1) gene cause Lenz-Majewski syndrome. · 2014 · https://pubmed.ncbi.nlm.nih.gov/24241535/ · DOI 10.1038/ng.2829
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19) · lines 262–268
AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human genetics and patient fibroblast synthesis assays. · source_derived_draft · unverified_draft
## l-serine-pss1-feedback Failure of a feedback brake can increase lipid production. PTDSS1 variants from Lenz-Majewski syndrome markedly reduced product inhibition by phosphatidylserine and increased phosphatidylserine synthesis in patient fibroblasts. Model: Human genetics and patient fibroblast synthesis assays. Limitations: These gain-of-function variants are not serine shortage or proof of an effect from phosphatidylserine supplements. Evidence access: Primary abstract Gain-of-function mutations in the phosphatidylserine synthase 1 (PTDSS1) gene cause Lenz-Majewski syndrome. · 2014 · https://pubmed.ncbi.nlm.nih.gov/24241535/ · DOI 10.1038/ng.2829
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.