Glycerolipid / triacylglycerol biosynthesis (glycerol-3-phosphate and DHAP routes)

Triacylglycerol (TAG) is the principal energy-storage lipid of eukaryotic cells. It is assembled from a three-carbon glycerol backbone and fatty acyl-CoAs, and the pathway's intermediates phosphatidic acid (PA) and diacylglycerol (DAG) are also the branch points to the membrane glycerophospholipids. Lysophosphatidic acid (LPA) is formed either by sn-1 acylation of glycerol-3-phosphate (glycerol-3-phosphate acyltransferase, GPAT) or by acylation of dihydroxyacetone phosphate followed by NADPH-dependent reduction of 1-acyl-DHAP; in fungi the same GPAT enzymes accept both acceptors, whereas the DHAP acyltransferase of animals belongs to peroxisomal ether-lipid synthesis. LPA is acylated at sn-2 to PA by 1-acylglycerol-3-phosphate O-acyltransferases (LPAATs) of the AGPAT family and, in fungi, also by MBOAT-family and lipid-droplet acyltransferases. A Mg2+-dependent lipin-family phosphatidate phosphatase, a soluble enzyme that acts on membranes, dephosphorylates PA to DAG. DAG is finally esterified at sn-3 either with an acyl-CoA by the diacylglycerol O-acyltransferases (the MBOAT-family DGAT1 and the DGAT2-family enzymes) or, independently of acyl-CoA, by a phospholipid:diacylglycerol acyltransferase (PDAT) that transfers an acyl chain from a glycerophospholipid. Synthesis takes place on the endoplasmic reticulum and on lipid droplets, into which TAG is packaged; in animals the first acylation is also performed at the mitochondrial outer membrane. Inherited defects in the mammalian enzymes cause metabolic disease (AGPAT2 congenital generalized lipodystrophy, LPIN1 recurrent rhabdomyolysis, DGAT1 congenital diarrhoea).

MODULE:triacylglycerol_biosynthesisDRAFTCONCRETEMetabolic Pathwaymodules/triacylglycerol_biosynthesis.yaml
triglyceride biosynthetic processGO:0019432 phosphatidic acid biosynthetic processGO:0006654 diacylglycerol biosynthetic processGO:0006651
YeastPathways:TRIGLSYN-PWY
diacylglycerol and triacylglycerol biosynthesis (S. cerevisiae, SGD YeastPathways)
YeastCyc lists GPT2/SCT1 (RXN-1381), SLC1 (RXN-1623), DPP1/LPP1/PAH1 (PHOSPHATIDATE-PHOSPHATASE-RXN), DGA1 (DIACYLGLYCEROL-O-ACYLTRANSFERASE-RXN) and LRO1 (RXN-1641), plus a gene-less DAG transacylase (RXN-12383) and the DGK1 DAG kinase reaction (RXN-12959). PAH1 was retained as the PA phosphatase; DPP1 and LPP1 were not (PMID:22345606); ALE1 and LOA1 were added as further LPAATs; RXN-12383 has no yeast enzyme and was left out; DGK1 catalyses the reverse, PA-forming reaction and is outside the module.
YeastPathways:PWY3O-6635
superpathway of phosphatidate biosynthesis (S. cerevisiae, SGD YeastPathways)
Combines the glycerol-3-phosphate and DHAP routes to PA with GPD1/GPD2 glycerol-3-phosphate dehydrogenase. The GPAT/DHAPAT (GPT2, SCT1), AYR1 and SLC1 assignments were retained; glycerol-3-phosphate supply by GPD1/GPD2 is modelled in glycerol_metabolism.
YeastPathways:PWY3O-6407
phosphatidate biosynthesis I (the dihydroxyacetone pathway) (S. cerevisiae, SGD YeastPathways)
DHAP acylation by GPT2/SCT1 (RXN3O-5279), 1-acyl-DHAP reduction by AYR1 (RXN3O-9800) and LPA acylation by SLC1. Retained as the DHAP-route variant.
YeastPathways:PWY3O-6499
phosphatidate biosynthesis II (the glycerol-3-phosphate pathway) (S. cerevisiae, SGD YeastPathways)
Glycerol-3-phosphate acylation by GPT2/SCT1 and LPA acylation by SLC1, preceded by GPD1/GPD2. Retained as the glycerol-3-phosphate-route variant.
GO:0019432
triglyceride biosynthetic process
The module as a whole synthesises triacylglycerol (GO:0019432).
GO:0006654
phosphatidic acid biosynthetic process
The LPA-forming and LPA-acylating steps build phosphatidic acid, the shared intermediate (GO:0006654).
GO:0006651
diacylglycerol biosynthetic process
Lipin-family PA phosphatases produce diacylglycerol, the branch point to TAG and phospholipids (GO:0006651).
PMID:22345606
Metabolism and regulation of glycerolipids in the yeast Saccharomyces cerevisiae.
PA is made in the ER by the SCT1- and GPT2-encoded glycerol-3-P acyltransferases and the SLC1- and ALE1-encoded lysoPA acyltransferases; the GPATs also use dihydroxyacetone-P, whose acyl product is reduced by the LD- and ER-associated AYR1 reductase; PAH1 provides DAG that DGA1 (acyl-CoA-dependent) and LRO1 (phospholipid-dependent) acylate to TAG; DPP1 and LPP1 are not involved in de novo TAG synthesis.
PMID:11544256
The initial step of the glycerolipid pathway: identification of glycerol 3-phosphate/dihydroxyacetone phosphate dual substrate acyltransferases in Saccharomyces cerevisiae.
GAT1 (= GPT2, YKR067w) and GAT2 (= SCT1, YBL011w) are the major yeast G-3-P acyltransferases and both are G-3-P/dihydroxyacetone phosphate dual-substrate sn-1 acyltransferases.
PMID:10049376
Redundant systems of phosphatidic acid biosynthesis via acylation of glycerol-3-phosphate or dihydroxyacetone phosphate in the yeast Saccharomyces cerevisiae.
Gat1p in lipid particles and ER accepts both glycerol-3-phosphate and DHAP, and in vivo labelling shows that both precursors are incorporated as the glycerolipid backbone.
PMID:10617610
1-Acyldihydroxyacetone-phosphate reductase (Ayr1p) of the yeast Saccharomyces cerevisiae encoded by the open reading frame YIL124w is a major component of lipid particles.
AYR1 encodes the NADPH-dependent 1-acyl-DHAP reductase of lipid particles and ER; microsomes contain at least one further reductase.
PMID:9401016
Biosynthesis of phosphatidic acid in lipid particles and endoplasmic reticulum of Saccharomyces cerevisiae.
Lipid particles acylate glycerol-3-phosphate to PA in two steps that require Gat1p and Slc1p; the ER has a second, independent PA-synthesis system.
PMID:17726007
Identification of a novel lysophospholipid acyltransferase in Saccharomyces cerevisiae.
The MBOAT-family LPT1 (= ALE1) acylates lysophospholipids including LPA and works with Slc1 to incorporate unsaturated acyl chains.
PMID:22090344
YPR139c/LOA1 encodes a novel lysophosphatidic acid acyltransferase associated with lipid droplets and involved in TAG homeostasis.
LOA1 (VPS66) is a lipid-droplet LPA acyltransferase with a preference for oleoyl-CoA whose loss reduces TAG.
PMID:16467296
The Saccharomyces cerevisiae Lipin homolog is a Mg2+-dependent phosphatidate phosphatase enzyme.
PAH1 encodes the Mg2+-dependent PA phosphatase, present in membrane and cytosolic fractions; pah1 mutants accumulate PA and have less DAG and TAG; human LPIN1 has the same activity.
PMID:10747858
A lecithin cholesterol acyltransferase-like gene mediates diacylglycerol esterification in yeast.
LRO1 esterifies DAG using phosphatidylcholine as acyl donor and is a major contributor to TAG synthesis.
PMID:10829075
Phospholipid:diacylglycerol acyltransferase: an enzyme that catalyzes the acyl-CoA-independent formation of triacylglycerol in yeast and plants.
PDAT synthesises TAG from phospholipid acyl donors and DAG in yeast and plants; budding-yeast PDAT and its fission-yeast and Arabidopsis relatives form a distinct LCAT-related branch.
PMID:11751875
The DGA1 gene determines a second triglyceride synthetic pathway in yeast.
DGA1, the sole DGAT2-family gene in yeast, is an acyl-CoA:DAG acyltransferase; dga1 lro1 double mutants almost abolish TAG synthesis, and the residual activity depends on the sterol acyltransferase ARE2.
PMID:11751830
Synthesis of triacylglycerols by the acyl-coenzyme A:diacyl-glycerol acyltransferase Dga1p in lipid particles of the yeast Saccharomyces cerevisiae.
Dga1p is the major DAGAT activity of lipid particles; Lro1p and Dga1p are the major contributors to cellular TAG synthesis.
PMID:18458076
Characterization of the yeast DGK1-encoded CTP-dependent diacylglycerol kinase.
DGK1 converts DAG back to PA using CTP; it is the reverse of the lipin step and is recorded as context, not as a module part.
file:human/GPAM/GPAM-ai-review.yaml
GPAM gene review (human)
Glycerol-3-phosphate acyltransferase 1 (UniProtKB:Q9HCL2, GO:0004366) matches the completed human GPAM review.
file:human/AGPAT2/AGPAT2-ai-review.yaml
AGPAT2 gene review (human)
1-acylglycerol-3-phosphate O-acyltransferase 2 (UniProtKB:O15120, GO:0003841) matches the completed human AGPAT2 review.
file:human/LPIN1/LPIN1-ai-review.yaml
LPIN1 gene review (human)
Lipin-1 phosphatidate phosphatase (UniProtKB:Q14693, GO:0008195) matches the completed human LPIN1 review.
file:human/DGAT1/DGAT1-ai-review.yaml
DGAT1 gene review (human)
Diacylglycerol O-acyltransferase 1 (UniProtKB:O75907, GO:0004144) matches the completed human DGAT1 review.
file:human/DGAT2/DGAT2-ai-review.yaml
DGAT2 gene review (human)
Diacylglycerol O-acyltransferase 2 (UniProtKB:Q96PD7, GO:0004144) matches the completed human DGAT2 review.

GENERALIZE (YeastPathways project, 2026-10). The former human-only module (GPAM -> AGPAT2 -> LPIN1 -> DGAT1/DGAT2) was broadened to eukaryotic glycerolipid/TAG synthesis. All human leaves, families and gene-review evidence are kept unchanged. Structural changes: (1) LPA formation is now a ONE_OR_MORE variant set of the glycerol-3-phosphate route and the DHAP route. The G3P-acylation node holds two GPAT annotons because animal GPAM (PANTHER PTHR12563, mitochondrial outer membrane) and fungal GPT2/SCT1 (PTHR31605, ER and lipid droplets) are not in the same PANTHER family; the fungal enzymes are dual G3P/DHAP acyltransferases (PMID:11544256), so they also ground the DHAP-acylation step. The animal DHAP acyltransferase GNPAT acts in peroxisomal ether-lipid synthesis (ether_lipid_plasmalogen_biosynthesis) and is not used here. (2) LPA acylation gained fungal exemplars: SLC1 and S. pombe SPAC1851.02 join AGPAT2 in PTHR10434, and two further annotons were added for the MBOAT-family ALE1/LPT1 (PTHR13906:SF4) and the lipid-droplet LOA1/VPS66 (PTHR23063:SF60). ICT1 (Q12385), reported as an LPAAT, was not added because its contribution to de novo PA synthesis is not established in the cached literature. (3) PAH1 and S. pombe ned1 were added to the lipin family node. (4) DAG acylation is a ONE_OR_MORE variant set of acyl-CoA-dependent DGAT (DGAT1 MBOAT; DGAT2 family with yeast DGA1 and S. pombe dga1) and acyl-CoA-independent PDAT (LRO1, S. pombe plh1). The sterol acyltransferase ARE2 (PTHR10408, the DGAT1 family) contributes a minor DGAT activity in yeast (PMID:11751875) but is not used as an exemplar because its principal function is steryl-ester synthesis. YeastCyc corrections: DPP1 and LPP1, listed as PA phosphatases in TRIGLSYN-PWY, are broad-specificity lipid phosphate phosphatases that are not involved in de novo TAG synthesis (PMID:22345606) and were not added; ALE1 and LOA1 are missing from YeastCyc and were added; RXN-12383 (DAG:DAG transacylase) has no yeast gene and is not modelled; DGK1 (RXN-12959) runs the reverse reaction (DAG -> PA with CTP, PMID:18458076) and is noted as a regulator of the PA/DAG balance outside the module; GPD1/GPD2 glycerol-3-phosphate supply is in glycerol_metabolism. Compartments: YeastCyc-derived GO-CAMs put every activity in cytosol, but the yeast GPATs and SLC1 are ER and lipid-droplet enzymes, AYR1 is on lipid droplets and ER, DGA1 is enriched on lipid droplets, and PAH1 is a soluble enzyme that acts on the nuclear/ER membrane (PMID:22345606, PMID:10617610, PMID:11751830, PMID:16467296). GO-CAM disagreements: (a) all four YeastPathways models place activities in cytosol; (b) YeastPathways_TRIGLSYN-PWY includes DPP1 and LPP1 as PA phosphatases and DGK1 as part of TAG biosynthesis; (c) the PomBase model 6796b94c00005663 also contains SPAC6G10.03c as an LPA acyltransferase (UniProt names it a probable mitochondrial cardiolipin-specific deacylase), SPAC977.08/ayr2 as a second 1-acyl-DHAP reductase (UniProt: uncharacterized oxidoreductase), ptp4/dgk1, pld1, gpd1/gpd2 and ept1, which are either unverified for this activity or outside this module. Plant seed-oil assembly is modelled separately in seed_triacylglycerol_biosynthesis; the CDP-diacylglycerol and Kennedy branches that consume PA and DAG are cdp_dag_phospholipid_synthesis and kennedy_pathway_phospholipid_synthesis.

12Nodes
7Parts
2Variant Sets
4Variants
11Annotons
4Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:triacylglycerol_biosynthesis deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Reaction chaining (advisory)

✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.

  • lpa_formation → lpa_acylation [NOT_CHECKED]
    LPA (a non-CoA intermediate) made by either route is the LPAAT acceptor; the CoA released upstream is not the downstream substrate.
  • lpa_acylation → pa_dephosphorylation [NOT_CHECKED]
    Phosphatidic acid is the lipin/PAH1 substrate.
  • pa_dephosphorylation → dag_acylation [NOT_CHECKED]
    DAG made by lipin/PAH1 is the acceptor for DGAT and PDAT.

Function consistency and core coverage

22 gene-function check(s) reflected in core functions · 0 conflict(s) · 2 evidence or coverage gap(s) (40 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
gpam_activity GPAM / GPAT1 (human)
UniProtKB:Q9HCL2
Family Representative 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
fungal_gpat_activity GPT2 / GAT1 (Saccharomyces cerevisiae)
UniProtKB:P36148
Family Representative 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
fungal_gpat_activity SCT1 / GAT2 (Saccharomyces cerevisiae)
UniProtKB:P32784
Family Representative 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
fungal_gpat_activity sct1 / SPBC1718.04 (Schizosaccharomyces pombe)
UniProtKB:Q9P7P0
Family Representative 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
fungal_dhapat_activity GPT2 / GAT1 (Saccharomyces cerevisiae)
UniProtKB:P36148
Family Representative 		glycerone-phosphate O-acyltransferase activity
GO:0016287 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
fungal_dhapat_activity SCT1 / GAT2 (Saccharomyces cerevisiae)
UniProtKB:P32784
Family Representative 		glycerone-phosphate O-acyltransferase activity
GO:0016287 		Annotation Supported
A retained annotation or curated replacement supports this function, but core_functions does not yet reflect it.
fungal_dhapat_activity sct1 / SPBC1718.04 (Schizosaccharomyces pombe)
UniProtKB:Q9P7P0
Family Representative 		glycerone-phosphate O-acyltransferase activity
GO:0016287 		Non Core Supported
The review explicitly retains this function as non-core; promotion into core_functions is not implied.
ayr1_activity AYR1 (Saccharomyces cerevisiae)
UniProtKB:P40471
Family Representative 		acylglycerone-phosphate reductase (NADP+) activity
GO:0000140 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
ayr1_activity ayr1 (Schizosaccharomyces pombe)
UniProtKB:Q09851
Family Representative 		acylglycerone-phosphate reductase (NADP+) activity
GO:0000140 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
agpat2_activity AGPAT2 / LPAAT-beta (human)
UniProtKB:O15120
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
agpat2_activity SLC1 (Saccharomyces cerevisiae)
UniProtKB:P33333
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
agpat2_activity slc1 / SPAC1851.02 (Schizosaccharomyces pombe)
UniProtKB:Q9US20
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
mboat_lpaat_activity ALE1 / LPT1 (Saccharomyces cerevisiae)
UniProtKB:Q08548
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
mboat_lpaat_activity ale1 (Schizosaccharomyces pombe)
UniProtKB:O42916
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Non Core Supported
The review explicitly retains this function as non-core; promotion into core_functions is not implied.
loa1_lpaat_activity LOA1 / VPS66 (Saccharomyces cerevisiae)
UniProtKB:Q06508
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
loa1_lpaat_activity vps66 (Schizosaccharomyces pombe)
UniProtKB:Q9US27
Family Representative 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
lpin1_activity LPIN1 / lipin-1 (human)
UniProtKB:Q14693
Family Representative 		phosphatidate phosphatase activity
GO:0008195 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
lpin1_activity PAH1 (Saccharomyces cerevisiae)
UniProtKB:P32567
Family Representative 		phosphatidate phosphatase activity
GO:0008195 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
lpin1_activity ned1 (Schizosaccharomyces pombe)
UniProtKB:Q9UUJ6
Family Representative 		phosphatidate phosphatase activity
GO:0008195 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
dgat1_activity DGAT1 (human)
UniProtKB:O75907
Family Representative 		diacylglycerol O-acyltransferase activity
GO:0004144 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
dgat2_activity DGAT2 (human)
UniProtKB:Q96PD7
Family Representative 		diacylglycerol O-acyltransferase activity
GO:0004144 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
dgat2_activity DGA1 (Saccharomyces cerevisiae)
UniProtKB:Q08650
Family Representative 		diacylglycerol O-acyltransferase activity
GO:0004144 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
dgat2_activity dga1 (Schizosaccharomyces pombe)
UniProtKB:O74850
Family Representative 		diacylglycerol O-acyltransferase activity
GO:0004144 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
pdat_activity LRO1 (Saccharomyces cerevisiae)
UniProtKB:P40345
Family Representative 		phospholipid:diacylglycerol acyltransferase activity
GO:0046027 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
pdat_activity plh1 (Schizosaccharomyces pombe)
UniProtKB:O94680
Family Representative 		phospholipid:diacylglycerol acyltransferase activity
GO:0046027 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
gpam_activity GPAT / glycerophosphate O-acyltransferase family
PANTHER:PTHR12563
Family 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Family Function Unreviewed
Family review leaves GO:0004366 UNRESOLVED. The GPAM/GPAT1 branch in SF16 has directly demonstrated glycerol-3-phosphate acyltransferase activity. The family also contains GPAT2 and bacterial PlsB proteins, so this activity is not exclusive to SF16. DAPAT proteins introduce a different acceptor specificity. The exhaustive set of substrate-compatible branches remains unresolved; the GPAT1 experiment establishes a positive example rather than an exclusion of other GPAT enzymes.
fungal_gpat_activity fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase family
PANTHER:PTHR31605
Family 		glycerol-3-phosphate O-acyltransferase activity
GO:0004366 		Family Supported
Family review supports GO:0004366 FAMILY_WIDE. Asserted by triacylglycerol_biosynthesis; accepted by GPT2, SCT1 and SPBC1718.04.
fungal_dhapat_activity fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase family
PANTHER:PTHR31605
Family 		glycerone-phosphate O-acyltransferase activity
GO:0016287 		Family Supported
Family review supports GO:0016287 FAMILY_WIDE. DHAP acyltransferase activity; accepted by GPT2 and SCT1, kept as non-core by S. pombe.
ayr1_activity AYR1 1-acyldihydroxyacetone-phosphate reductase family (SDR)
PANTHER:PTHR44169:SF6
Family 		acylglycerone-phosphate reductase (NADP+) activity
GO:0000140 		Family Supported
Family review supports GO:0000140 for PANTHER:PTHR44169:SF6. Asserted by triacylglycerol_biosynthesis; accepted by AYR1 and ayr1.
agpat2_activity AGPAT / 1-acylglycerol-3-phosphate O-acyltransferase family
PANTHER:PTHR10434
Family 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Family Supported
Family review supports GO:0003841 FAMILY_WIDE. Asserted by triacylglycerol_biosynthesis; accepted by S. cerevisiae SLC1, S. pombe SPAC1851.02 and human AGPAT2 in two subfamilies.
mboat_lpaat_activity ALE1 / LPLAT MBOAT family
PANTHER:PTHR13906:SF4
Family 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Family Supported
Family review supports GO:0003841 for PANTHER:PTHR13906:SF4. ALE1-type broad-specificity LPLATs (SF4), as triacylglycerol_biosynthesis selects; accepted by ALE1, kept as non-core by ale1.
loa1_lpaat_activity LOA1 glycerolipid acyltransferase subfamily
PANTHER:PTHR23063:SF60
Family 		1-acylglycerol-3-phosphate O-acyltransferase activity
GO:0003841 		Family Supported
Family review supports GO:0003841 for PANTHER:PTHR23063:SF60. LOA1 (SF60), selected by triacylglycerol_biosynthesis, and the LPCAT1/2 and GPAT3 subfamilies whose reviews keep it as a secondary activity.
lpin1_activity Lipin / phosphatidate phosphatase family
PANTHER:PTHR12181
Family 		phosphatidate phosphatase activity
GO:0008195 		Family Supported
Family review supports GO:0008195 FAMILY_WIDE. Asserted by triacylglycerol_biosynthesis; accepted by PAH1, ned1 and LPIN1-3.
dgat1_activity DGAT1 / MBOAT acyltransferase family
PANTHER:PTHR10408:SF7
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR10408:SF7. DGAT1 subfamilies only (SF7, SF12, SF22). triacylglycerol_biosynthesis selects the base family for DGAT1, which also takes in the sterol acyltransferases.
dgat1_activity DGAT1 / MBOAT acyltransferase family
PANTHER:PTHR10408:SF12
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR10408:SF12. DGAT1 subfamilies only (SF7, SF12, SF22). triacylglycerol_biosynthesis selects the base family for DGAT1, which also takes in the sterol acyltransferases.
dgat1_activity DGAT1 / MBOAT acyltransferase family
PANTHER:PTHR10408:SF22
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR10408:SF22. DGAT1 subfamilies only (SF7, SF12, SF22). triacylglycerol_biosynthesis selects the base family for DGAT1, which also takes in the sterol acyltransferases.
dgat2_activity DGAT2 / MOGAT-DGAT2 acyltransferase family
PANTHER:PTHR12317:SF0
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR12317:SF0. DGAT2 subfamilies; triacylglycerol_biosynthesis selects the base family, which also takes in MOGAT and AWAT.
dgat2_activity DGAT2 / MOGAT-DGAT2 acyltransferase family
PANTHER:PTHR12317:SF14
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR12317:SF14. DGAT2 subfamilies; triacylglycerol_biosynthesis selects the base family, which also takes in MOGAT and AWAT.
dgat2_activity DGAT2 / MOGAT-DGAT2 acyltransferase family
PANTHER:PTHR12317:SF63
Family 		diacylglycerol O-acyltransferase activity
GO:0004144 		Family Supported
Family review supports GO:0004144 for PANTHER:PTHR12317:SF63. DGAT2 subfamilies; triacylglycerol_biosynthesis selects the base family, which also takes in MOGAT and AWAT.
pdat_activity PDAT (LCAT-related) subfamily
PANTHER:PTHR11440:SF105
Family 		phospholipid:diacylglycerol acyltransferase activity
GO:0046027 		Family Supported
Family review supports GO:0046027 for PANTHER:PTHR11440:SF105. PDAT (SF105), as triacylglycerol_biosynthesis selects.

Gene-review completeness (22/22 grounded genes reviewed)

21 complete review(s) · 10 with deep research · 0 missing review · 12 reviewed but lacking deep research

Gene Review Complete Deep research
AGPAT2 O15120 ✓ 25/31 ✗
ale1 O42916 ✓ ✓ ✗
ALE1 Q08548 ✓ ✓ ✓
AYR1 P40471 ✓ ✓ ✓
ayr1 Q09851 ✓ ✓ ✗
dga1 O74850 ✓ ✓ ✗
DGA1 Q08650 ✓ ✓ ✓
DGAT1 O75907 ✓ ✓ ✗
DGAT2 Q96PD7 ✓ ✓ ✗
GPAM Q9HCL2 ✓ ✓ ✓
GPT2 P36148 ✓ ✓ ✓
LOA1 Q06508 ✓ ✓ ✓
LPIN1 Q14693 ✓ ✓ ✗
LRO1 P40345 ✓ ✓ ✓
ned1 Q9UUJ6 ✓ ✓ ✗
PAH1 P32567 ✓ ✓ ✓
plh1 O94680 ✓ ✓ ✗
SCT1 P32784 ✓ ✓ ✓
SLC1 P33333 ✓ ✓ ✓
SPAC1851.02 Q9US20 ✓ ✓ ✗
SPBC1718.04 Q9P7P0 ✓ ✓ ✗
vps66 Q9US27 ✓ ✓ ✗

Details

Context
EukaryotaNCBITaxon:2759
endoplasmic reticulum membraneGO:0005789 lipid dropletGO:0005811 mitochondrial outer membraneGO:0005741
Glycerolipid / triacylglycerol biosynthesisMetabolic Pathwaytriacylglycerol_biosynthesis
triglyceride biosynthetic processGO:0019432 phosphatidic acid biosynthetic processGO:0006654 diacylglycerol biosynthetic processGO:0006651
Context
EukaryotaNCBITaxon:2759
endoplasmic reticulum membraneGO:0005789 lipid dropletGO:0005811 mitochondrial outer membraneGO:0005741

Connections

LPA made via glycerol-3-phosphate or DHAP is acylated at sn-2 to phosphatidic acid.
Phosphatidic acid is dephosphorylated by lipin/PAH1 to DAG.
Lipin-made DAG is esterified by DGAT or PDAT to triacylglycerol.
Part 1: lysophosphatidic acid formation
Lysophosphatidic acid formation (glycerol-3-phosphate or DHAP route)Metabolic Pathwaylpa_formation

sn-1 acylation of glycerol-3-phosphate gives LPA directly; acylation of DHAP gives 1-acyl-DHAP, which is reduced with NADPH to LPA. Both routes operate in yeast and in fungi are served by the same dual-substrate GPATs.

Variant set: Glycerol backbone acceptor by substrate route (One Or More)
Glycerol-3-phosphate routeMetabolic Pathwayg3p_route
Part 1: G3P acylation (glycerol-3-phosphate -> LPA)
Glycerol-3-phosphate acyltransferase (GPAM / fungal GPT2-SCT1)Reactiong3p_acylation

Annotons

GPAM: glycerol-3-phosphate O-acyltransferase (animal mitochondrial GPAT)
gpam_activity
Participant: Family: GPAT / glycerophosphate O-acyltransferase family
Family:
GPAT / glycerophosphate O-acyltransferase familyPANTHER:PTHR12563
Representative Members: GPAM / GPAT1 (human)UniProtKB:Q9HCL2

Function

glycerol-3-phosphate O-acyltransferase activityGO:0004366
Substrates: sn-glycerol 3-phosphate long-chain acyl-CoA (prefers saturated)
Products: 1-acyl-sn-glycerol-3-phosphate (lysophosphatidic acid, LPA) CoA

Locations

mitochondrial outer membraneGO:0005741

Acylate glycerol-3-phosphate at sn-1 to LPA.

GPT2/SCT1: dual-substrate glycerol-3-phosphate O-acyltransferase (fungal GPAT)
fungal_gpat_activity
Participant: Family: fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase family
Family:
fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase familyPANTHER:PTHR31605
Representative Members: GPT2 / GAT1 (Saccharomyces cerevisiae)UniProtKB:P36148 SCT1 / GAT2 (Saccharomyces cerevisiae)UniProtKB:P32784 sct1 / SPBC1718.04 (Schizosaccharomyces pombe)UniProtKB:Q9P7P0

Function

glycerol-3-phosphate O-acyltransferase activityGO:0004366
Substrates: sn-glycerol 3-phosphate long-chain acyl-CoA
Products: 1-acyl-sn-glycerol-3-phosphate (LPA) CoA

Locations

endoplasmic reticulum membraneGO:0005789 lipid dropletGO:0005811

Acylate glycerol-3-phosphate at sn-1 to LPA (fungal ER/lipid-droplet GPAT; also uses DHAP).

Dihydroxyacetone phosphate routeMetabolic Pathwaydhap_route

DHAP is acylated at sn-1 and the 1-acyl-DHAP is reduced with NADPH to LPA. In yeast both steps occur on lipid droplets and in the ER; in labelling experiments DHAP and G3P both contribute to the glycerolipid backbone (PMID:10049376).

Connections

Part 1: DHAP acylation (DHAP -> 1-acyl-DHAP)
Glycerone-phosphate O-acyltransferase activity of fungal GPATsReactiondhap_acylation

Annotons

GPT2/SCT1: glycerone-phosphate O-acyltransferase
fungal_dhapat_activity
Participant: Family: fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase family
Family:
fungal GPT2/SCT1 glycerol-3-phosphate/DHAP acyltransferase familyPANTHER:PTHR31605
Representative Members: GPT2 / GAT1 (Saccharomyces cerevisiae)UniProtKB:P36148 SCT1 / GAT2 (Saccharomyces cerevisiae)UniProtKB:P32784 sct1 / SPBC1718.04 (Schizosaccharomyces pombe)UniProtKB:Q9P7P0

Function

glycerone-phosphate O-acyltransferase activityGO:0016287
Substrates: dihydroxyacetone phosphate (glycerone phosphate) long-chain acyl-CoA
Products: 1-acyl-dihydroxyacetone phosphate CoA

Locations

endoplasmic reticulum membraneGO:0005789 lipid dropletGO:0005811

Acylate DHAP at sn-1 (the same fungal enzymes as the G3P acylation).

Part 2: 1-acyl-DHAP reduction (1-acyl-DHAP -> LPA)
NADPH-dependent 1-acyl-DHAP reductase (AYR1)Reactionacyl_dhap_reduction

Annotons

AYR1: acylglycerone-phosphate reductase (NADP+)
ayr1_activity
Participant: Family: AYR1 1-acyldihydroxyacetone-phosphate reductase family (SDR)
Family:
AYR1 1-acyldihydroxyacetone-phosphate reductase family (SDR)
Representative Members: AYR1 (Saccharomyces cerevisiae)UniProtKB:P40471 ayr1 (Schizosaccharomyces pombe)UniProtKB:Q09851

Function

acylglycerone-phosphate reductase (NADP+) activityGO:0000140
Substrates: 1-acyl-dihydroxyacetone phosphate NADPH
Products: 1-acyl-sn-glycerol-3-phosphate (LPA) NADP+

Locations

lipid dropletGO:0005811 endoplasmic reticulum membraneGO:0005789

Reduce 1-acyl-DHAP to LPA with NADPH.

Part 2: LPA acylation (LPA -> phosphatidic acid)
1-Acylglycerol-3-phosphate O-acyltransferases (AGPAT/SLC1, MBOAT ALE1, LOA1)Reactionlpa_acylation

sn-2 acylation of LPA. The AGPAT-family enzyme (AGPAT2 in animals, SLC1 in yeast) is the main activity; fungi add the MBOAT-family lysophospholipid acyltransferase ALE1 and the lipid-droplet LOA1.

Annotons

AGPAT2/SLC1: 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT family)
agpat2_activity
Participant: Family: AGPAT / 1-acylglycerol-3-phosphate O-acyltransferase family
Family:
AGPAT / 1-acylglycerol-3-phosphate O-acyltransferase familyPANTHER:PTHR10434
Representative Members: AGPAT2 / LPAAT-beta (human)UniProtKB:O15120 SLC1 (Saccharomyces cerevisiae)UniProtKB:P33333 slc1 / SPAC1851.02 (Schizosaccharomyces pombe)UniProtKB:Q9US20

Function

1-acylglycerol-3-phosphate O-acyltransferase activityGO:0003841
Substrates: lysophosphatidic acid (LPA) long-chain acyl-CoA
Products: phosphatidic acid (PA) CoA

Locations

endoplasmic reticulum membraneGO:0005789

Acylate LPA at sn-2 to phosphatidic acid.

ALE1/LPT1: MBOAT-family lysophospholipid acyltransferase acting on LPA
mboat_lpaat_activity
Participant: Family: ALE1 / LPLAT MBOAT family
Family:
ALE1 / LPLAT MBOAT familyPANTHER:PTHR13906:SF4
Representative Members: ALE1 / LPT1 (Saccharomyces cerevisiae)UniProtKB:Q08548 ale1 (Schizosaccharomyces pombe)UniProtKB:O42916

Function

1-acylglycerol-3-phosphate O-acyltransferase activityGO:0003841
Substrates: lysophosphatidic acid (LPA) acyl-CoA (incorporates unsaturated chains)
Products: phosphatidic acid (PA) CoA

Locations

endoplasmic reticulum membraneGO:0005789

Secondary ER LPAAT that also remodels other lysophospholipids (MBOAT family).

LOA1/VPS66: lipid-droplet lysophosphatidic acid acyltransferase
loa1_lpaat_activity
Participant: Family: LOA1 glycerolipid acyltransferase subfamily
Family:
LOA1 glycerolipid acyltransferase subfamilyPANTHER:PTHR23063:SF60
Representative Members: LOA1 / VPS66 (Saccharomyces cerevisiae)UniProtKB:Q06508 vps66 (Schizosaccharomyces pombe)UniProtKB:Q9US27

Function

1-acylglycerol-3-phosphate O-acyltransferase activityGO:0003841
Substrates: lysophosphatidic acid (LPA) oleoyl-CoA (preferred)
Products: phosphatidic acid (PA) CoA

Locations

lipid dropletGO:0005811 endoplasmic reticulumGO:0005783

Lipid-droplet LPAAT that channels PA toward TAG.

Part 3: PA dephosphorylation (PA -> DAG)
Mg2+-dependent phosphatidate phosphatase (lipin / PAH1)Reactionpa_dephosphorylation

Annotons

Lipin/PAH1: phosphatidate phosphatase (PAP1)
lpin1_activity
Participant: Family: Lipin / phosphatidate phosphatase family
Family:
Lipin / phosphatidate phosphatase familyPANTHER:PTHR12181
Representative Members: LPIN1 / lipin-1 (human)UniProtKB:Q14693 PAH1 (Saccharomyces cerevisiae)UniProtKB:P32567 ned1 (Schizosaccharomyces pombe)UniProtKB:Q9UUJ6

Function

phosphatidate phosphatase activityGO:0008195
Substrates: phosphatidic acid (PA; Mg2+) H2O
Products: 1,2-diacyl-sn-glycerol (DAG) phosphate

Locations

endoplasmic reticulum membraneGO:0005789

Dephosphorylate PA to DAG on the ER membrane (soluble enzyme recruited to membranes).

Part 4: DAG acylation (DAG -> triacylglycerol)
Diacylglycerol acylation to TAG (acyl-CoA-dependent DGAT or phospholipid-dependent PDAT)Metabolic Pathwaydag_acylation
Variant set: Acyl donor for the final acylation by acyl donor / enzyme family (One Or More)
Acyl-CoA:diacylglycerol acyltransferase (DGAT1 MBOAT and DGAT2 families)Reactionacyl_coa_dgat

Annotons

DGAT1: diacylglycerol O-acyltransferase (MBOAT)
dgat1_activity
Participant: Family: DGAT1 / MBOAT acyltransferase family
Family:
DGAT1 / MBOAT acyltransferase family
Representative Members: DGAT1 (human)UniProtKB:O75907

Function

diacylglycerol O-acyltransferase activityGO:0004144
Substrates: 1,2-diacyl-sn-glycerol (DAG) long-chain acyl-CoA
Products: triacylglycerol (TAG) CoA

Locations

endoplasmic reticulum membraneGO:0005789

Esterify DAG at sn-3 to TAG (MBOAT family; absent as a dedicated DGAT from budding yeast).

DGAT2/DGA1: diacylglycerol O-acyltransferase (DGAT2 family)
dgat2_activity
Participant: Family: DGAT2 / MOGAT-DGAT2 acyltransferase family
Family:
DGAT2 / MOGAT-DGAT2 acyltransferase family
Representative Members: DGAT2 (human)UniProtKB:Q96PD7 DGA1 (Saccharomyces cerevisiae)UniProtKB:Q08650 dga1 (Schizosaccharomyces pombe)UniProtKB:O74850

Function

diacylglycerol O-acyltransferase activityGO:0004144
Substrates: 1,2-diacyl-sn-glycerol (DAG) long-chain acyl-CoA
Products: triacylglycerol (TAG) CoA

Locations

lipid dropletGO:0005811

Esterify DAG at sn-3 to TAG (DGAT2 family; ER/lipid droplet).

Phospholipid:diacylglycerol acyltransferase (PDAT, acyl-CoA-independent)Reactionpdat_route

An LCAT-related enzyme transfers the sn-2 acyl chain of a glycerophospholipid (mainly phosphatidylcholine) to DAG, giving TAG and a lysophospholipid. Present in fungi and plants (PMID:10829075); not found in animals.

Annotons

LRO1/plh1: phospholipid:diacylglycerol acyltransferase
pdat_activity
Participant: Family: PDAT (LCAT-related) subfamily
Family:
PDAT (LCAT-related) subfamilyPANTHER:PTHR11440:SF105
Representative Members: LRO1 (Saccharomyces cerevisiae)UniProtKB:P40345 plh1 (Schizosaccharomyces pombe)UniProtKB:O94680

Function

phospholipid:diacylglycerol acyltransferase activityGO:0046027
Substrates: 1,2-diacyl-sn-glycerol (DAG) phosphatidylcholine (acyl donor)
Products: triacylglycerol (TAG) 1-acyl-sn-glycero-3-phosphocholine (lysophosphatidylcholine)

Locations

endoplasmic reticulum membraneGO:0005789

Acyl-CoA-independent TAG synthesis from phospholipid acyl donors (fungi, plants).