The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
The requested target is Danio rerio (zebrafish) gpat3 (UniProt Q6DG38), annotated as glycerol-3-phosphate acyltransferase 3 (GPAT-3) and also referred to in the literature as AGPAT10/GPAT3 or AGPAT9-like in historical nomenclature. The retrieved authoritative biochemical literature on AGPAT10/GPAT3 explicitly reports high conservation with zebrafish sequences and discusses the naming ambiguity (GPAT3 vs AGPAT10), which aligns with the UniProt-provided alternate names and EC assignments for Q6DG38 (sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 8-9).
The glycerol-3-phosphate pathway for de novo glycerolipid synthesis proceeds via sequential acylations:
1) GPAT activity (EC 2.3.1.15): acyl-CoA + glycerol-3-phosphate (G3P) → lysophosphatidic acid (LPA) + CoA
2) AGPAT/LPAAT activity (EC 2.3.1.51): acyl-CoA + LPA → phosphatidic acid (PA) + CoA
PA is a central intermediate for synthesis of triacylglycerol (TAG) and glycerophospholipids (takeuchi2009biochemistryphysiologyand pages 1-2, sukumaran2009functionalcharacterizationof pages 4-6).
A key complication for GPAT3-family annotation is that some isoforms historically labeled “GPAT3” have been experimentally observed to behave primarily as AGPAT (LPA acyltransferase) under certain assay systems, producing PA from LPA rather than producing LPA from G3P; this is the basis of the AGPAT10/GPAT3 dual naming in the endocrine/molecular endocrinology literature (sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 2-3).
GPAT/AGPAT-family enzymes share conserved acyltransferase sequence motifs, including the catalytic HXXXXD motif, and additional motifs involved in acceptor/donor recognition. Reviews emphasize that these motifs and membrane topology shape substrate access and specificity in the GPAT/AGPAT family (yamashita2014glycerophosphateacylglycerophosphateacyltransferases pages 4-7). In AGPAT9-family work (closely related acyltransferases), conserved motifs (including NHX4D and EGTR) were used to classify and interpret activity (agarwal2007functionalcharacterizationof pages 6-7).
Most defensible functional annotation (orthology-supported): zebrafish gpat3 (Q6DG38) encodes an ER/microsome-associated acyltransferase in the GPAT/AGPAT superfamily that likely participates in PA production for glycerolipid synthesis. The strongest direct enzymology in the retrieved corpus comes from the human ortholog labeled AGPAT10/GPAT3, which catalyzes LPA + acyl-CoA → PA + CoA (sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 8-9).
Because UniProt Q6DG38 carries both GPAT and AGPAT-type EC numbers and multiple historical synonyms, the enzymatic “primary function” should be recorded with explicit nomenclature caution: the gene product belongs to a family classically associated with GPAT/AGPAT steps, and ortholog assays support robust LPA acyltransferase (AGPAT/LPAAT-like) activity (sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 2-3).
In biochemical characterization of human AGPAT10/GPAT3, activity was strongest with 1-oleoyl-LPA as acyl acceptor and oleoyl-CoA (C18:1) as acyl donor. Several alternative LPA acceptors (e.g., C16:0, C18:3, C20:4) produced ~50% lower activity than 1-oleoyl-LPA in the reported assays (sukumaran2009functionalcharacterizationof pages 8-9). The same work reported that the enzyme did not recognize other lysophospholipid headgroups (LPS, LPC, LPE, LPG, LPI) under their tested conditions, indicating preference for the LPA headgroup class (sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof pages 2-3).
For zebrafish gpat3, these specificity statements should be treated as inferred from orthology, because zebrafish-specific enzymatic assays were not identified in the retrieved sources.
Cell biology experiments on AGPAT10/GPAT3 and related AGPAT-family enzymes show endoplasmic reticulum (ER) localization: an AGPAT10/GPAT3-GFP fusion displayed an ER-like pattern and colocalized with an ER marker (Sec61-β), and AGPAT9-family GFP fusions colocalized with multiple ER markers and with AGPAT1 in CHO cells (sukumaran2009functionalcharacterizationof pages 4-6, agarwal2007functionalcharacterizationof pages 6-7). This supports annotating zebrafish gpat3 as ER-associated, again primarily on orthology/family grounds.
Direct zebrafish evidence in the retrieved set comes from a 2023 Disease Models & Mechanisms study using a tango2-deficient zebrafish model of rhabdomyolysis susceptibility. The authors describe that glycerolipid-pathway enzymes are ER/SR-localized and that ER/SR-derived membrane and cellular lipids are reduced in mutants; within this pathway, gpat3 expression is reported as normal at baseline but shows decreased expression under extrinsic stressors (caffeine or mechanical loading) (kim2023intrinsicandextrinsic pages 9-11). This provides DANRE evidence linking gpat3 to membrane/glycerolipid homeostasis under stress, but it does not directly establish the catalytic reaction or substrate specificity of zebrafish Gpat3.
The human AGPAT10/GPAT3 study reports:
- Enzyme activity in overexpression lysate assays on the order of ~2 nmol·min⁻¹·mg⁻¹ protein under their stated conditions and noted lack of detectable GPAT activity in that assay system (sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 4-6).
- Kinetic parameters (reported in Table 1 and associated figures): Km(acyl-CoA) = 2.7 mM; Vmax = 60 nmol/min/mg and Km(LPA) = 9.2 mM; Vmax = 14.19 nmol/min/mg (sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof media 4c33d1ff).
These values are quantitative support for a robust LPA acyltransferase-like function in the ortholog and provide a defensible basis for functional inference to zebrafish gpat3 (with appropriate caveats).
The 2023 zebrafish tango2-mutant study reports reductions in membrane lipid pools (including phosphatidylcholine at early larval stages) and altered TAG composition (with reductions enriched among 16–18 carbon fatty acid-containing TAG species), alongside stress-linked downregulation of several glycerolipid pathway enzymes; however, the extracted evidence available here did not include explicit numeric fold-changes for gpat3 itself (kim2023intrinsicandextrinsic pages 9-11).
The tango2 zebrafish model places glycerolipid pathway regulation (including stress-responsiveness of gpat3 expression) into the context of a clinically relevant phenotype (rhabdomyolysis susceptibility), strengthening the biological plausibility that gpat3 contributes to membrane lipid homeostasis and muscle resilience under stress (kim2023intrinsicandextrinsic pages 9-11).
A 2024 review of phospholipid acyltransferases frames GPAT/AGPAT enzymes as key nodes linking lipid synthesis to metabolic disease and cancer, and discusses therapeutic interest in modulating these enzymes (publication date May 2024, URL: https://doi.org/10.3390/cancers16112115). Although not DANRE-focused, this provides expert synthesis on pathway importance and translational relevance of GPAT3-family enzymes (korbecki2024; retrieved in the session metadata).
Even when gpat3 itself is not directly perturbed, zebrafish disease and metabolism models (e.g., tango2 deficiency) are being used to connect lipid pathway regulation to organismal phenotypes and to test environmental/extrinsic triggers, supporting gpat3’s relevance as a pathway component for experimental systems biology in vivo (kim2023intrinsicandextrinsic pages 9-11).
Recent mammalian cancer literature positions GPAT3 as a potential therapeutic lever in lipid metabolic reprogramming. For instance, a 2024 hepatocellular carcinoma study proposes GPAT3 targeting to overcome sorafenib resistance (publication date June 2024, URL: https://doi.org/10.7150/thno.92646). This is not DANRE evidence, but it is a concrete real-world application of the same enzyme family in drug response biology (session-retrieved paper metadata).
The following table consolidates the functional annotation items, explicitly distinguishing direct zebrafish evidence from ortholog-based inference.
| Annotation item | Key findings | Evidence & notes |
|---|---|---|
| Reaction | Likely catalyzes LPA acylation to PA: 1-acyl-sn-glycerol-3-phosphate + acyl-CoA → phosphatidic acid + CoA. For zebrafish Q6DG38, this is best treated as inferred from ortholog/UniProt naming, not directly shown in zebrafish. | Human AGPAT10/GPAT3 assays showed AGPAT/LPAAT activity and no detectable GPAT activity in that system; UniProt Q6DG38 names include EC 2.3.1.15 and EC 2.3.1.51, reflecting historical dual annotation/nomenclature ambiguity. In report text, label as functional inference from ortholog. (sukumaran2009functionalcharacterizationof pages 4-6, sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 2-3) |
| Substrates | Preferred acceptor is LPA; acyl donor is long-chain acyl-CoA, with strongest reported activity using oleoyl-CoA (C18:1) in human ortholog assays. | Human ortholog AGPAT10/GPAT3 preferred 1-oleoyl-LPA and oleoyl-CoA; other LPA species gave lower activity. This supports annotation of zebrafish gpat3 as an acyl-CoA-dependent lysophosphatidic acid acyltransferase-like enzyme. Inferred from human ortholog. (sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof pages 2-3) |
| Products | Product is phosphatidic acid (PA), a central intermediate for triacylglycerol and glycerophospholipid synthesis. | Human biochemical assays measured conversion of radiolabeled LPA to PA; reviews place GPAT/AGPAT family in the glycerol-3-phosphate pathway feeding TAG and phospholipid synthesis. (sukumaran2009functionalcharacterizationof pages 4-6, sukumaran2009functionalcharacterizationof pages 1-2, takeuchi2009biochemistryphysiologyand pages 1-2) |
| Enzyme class / EC | Member of the GPAT/AGPAT acyltransferase family; annotation is complicated by historical naming as GPAT3 vs AGPAT10/AGPAT9-like. | Reviews note GPAT/AGPAT family enzymes share acyltransferase motifs and catalyze sequential acylation in glycerolipid synthesis. Human AGPAT10/GPAT3 was concluded by some authors to behave as AGPAT rather than GPAT in their assay system. (yamashita2014glycerophosphateacylglycerophosphateacyltransferases pages 4-7, sukumaran2009functionalcharacterizationof pages 1-2, sukumaran2009functionalcharacterizationof pages 2-3) |
| Cellular localization | Endoplasmic reticulum (ER) localization is the strongest supported localization for the ortholog and likely for zebrafish gpat3. | Human AGPAT10/GPAT3-GFP colocalized with ER marker Sec61-β; AGPAT9 family proteins also localized to ER-like compartments. For zebrafish, ER localization is inferred from ortholog/family evidence, not directly demonstrated here. (sukumaran2009functionalcharacterizationof pages 4-6, sukumaran2009functionalcharacterizationof pages 8-9, agarwal2007functionalcharacterizationof pages 6-7) |
| Key motifs / domains | Expected to contain acyltransferase family motifs, especially HXXXXD catalytic motif and other conserved GPAT/AGPAT motifs; UniProt lists Plipid/glycerol_acylTrfase / PF01553 and LPCAT1-like features. | Reviews summarize four acyltransferase motifs, with HXXXXD central to catalysis and motif III important for acceptor binding; AGPAT9 paper notes conserved NHX4D and EGTR motifs in this family. Domain-level zebrafish annotation is therefore well supported by family conservation. (yamashita2014glycerophosphateacylglycerophosphateacyltransferases pages 4-7, agarwal2007functionalcharacterizationof pages 6-7) |
| Organism-specific evidence | Zebrafish-specific direct functional literature is limited in the retrieved evidence. Available zebrafish evidence is mainly indirect/transcriptomic rather than direct enzymology or knockout of gpat3 itself. | The safest DANRE annotation is: zebrafish gpat3 likely functions in glycerolipid/phospholipid synthesis based on orthology plus pathway-level fish evidence, but direct zebrafish enzyme assays or dedicated gpat3 loss-of-function studies were not identified in the gathered sources. (kim2023intrinsicandextrinsic pages 9-11) |
| Zebrafish pathway context | In zebrafish, gpat3 is linked to the glycerolipid/glycerol-3-phosphate pathway and membrane lipid homeostasis under stress. | In tango2 mutant zebrafish, glycerolipid-pathway enzymes were altered; gpat3 was normal at baseline but decreased under extrinsic stressors (caffeine or mechanical loading), alongside broader reductions in ER/SR-derived membrane lipids. This is zebrafish evidence, but it does not directly establish catalytic specificity. (kim2023intrinsicandextrinsic pages 9-11) |
| Quantitative kinetics / activity | Human ortholog data provide quantitative support: AGPAT10/GPAT3 activity in lysates was about ~2 nmol·min⁻¹·mg⁻¹ under stated conditions; kinetic table reported Km(acyl-CoA) 2.7 mM, Vmax 60 nmol/min/mg and Km(LPA) 9.2 mM, Vmax 14.19 nmol/min/mg. | These numbers are from recombinant/overexpression assays of the human ortholog and should be cited as ortholog-based biochemical evidence, not zebrafish-specific measurements. (sukumaran2009functionalcharacterizationof pages 4-6, sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof media 4c33d1ff, sukumaran2009functionalcharacterizationof media ede781db, sukumaran2009functionalcharacterizationof media 3e0cacd3, sukumaran2009functionalcharacterizationof media 0224c14a) |
| Substrate selectivity against other lysophospholipids | Human ortholog showed strong preference for LPA and did not appreciably use LPS, LPC, LPE, LPG, or LPI in the cited assays. | Useful for annotation because it argues against broad lysophospholipid acyltransferase activity under the tested conditions. Inference to zebrafish should be cautious but reasonable by orthology. (sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof pages 2-3, sukumaran2009functionalcharacterizationof media 4c33d1ff) |
| Recent (2023–2024) notes / applications | Recent literature emphasizes GPAT3-family relevance in lipid-stress adaptation and disease; zebrafish work links pathway dysregulation to muscle disease models, while mammalian studies position GPAT3 as a potential therapeutic node in cancer/drug resistance. | 2023 zebrafish tango2 model connected altered glycerolipid pathway regulation, including gpat3 stress responsiveness, to rhabdomyolysis susceptibility. 2024 review literature highlights GPAT/AGPAT enzymes as metabolic/cancer targets; a 2024 HCC study identified GPAT3 as a potential target to overcome sorafenib resistance, illustrating translational relevance of the family, though not zebrafish-specific. (kim2023intrinsicandextrinsic pages 9-11) |
Table: This table summarizes the strongest available functional annotation for Danio rerio gpat3 (UniProt Q6DG38), separating direct zebrafish evidence from ortholog-based inference. It is useful for reporting the enzyme’s likely reaction, localization, motifs, and the current limits of zebrafish-specific experimental support.
1) Zebrafish-specific enzymology is not present in the retrieved corpus. The strongest kinetic and substrate specificity data are from the human ortholog AGPAT10/GPAT3 (sukumaran2009functionalcharacterizationof pages 8-9, sukumaran2009functionalcharacterizationof media 4c33d1ff).
2) Zebrafish-specific phenotypes from direct gpat3 loss-of-function (CRISPR/morpholino) were not identified in the retrieved sources. The only direct DANRE evidence here is pathway-/stress-linked expression behavior in a tango2 mutant context (kim2023intrinsicandextrinsic pages 9-11).
3) Given the known naming ambiguity (GPAT vs AGPAT), definitive zebrafish annotation would benefit from targeted biochemical assays using zebrafish Gpat3 and direct genetic perturbation measuring LPA/PA pools and downstream TAG/phospholipid synthesis.
References
(sukumaran2009functionalcharacterizationof pages 1-2): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(sukumaran2009functionalcharacterizationof pages 8-9): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(takeuchi2009biochemistryphysiologyand pages 1-2): Kazuharu Takeuchi and Karen Reue. Biochemistry, physiology, and genetics of gpat, agpat, and lipin enzymes in triglyceride synthesis. American journal of physiology. Endocrinology and metabolism, 296 6:E1195-209, Jun 2009. URL: https://doi.org/10.1152/ajpendo.90958.2008, doi:10.1152/ajpendo.90958.2008. This article has 587 citations.
(sukumaran2009functionalcharacterizationof pages 4-6): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(sukumaran2009functionalcharacterizationof pages 2-3): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(yamashita2014glycerophosphateacylglycerophosphateacyltransferases pages 4-7): Atsushi Yamashita, Yasuhiro Hayashi, Naoki Matsumoto, Yoko Nemoto-Sasaki, Saori Oka, Takashi Tanikawa, and Takayuki Sugiura. Glycerophosphate/acylglycerophosphate acyltransferases. Biology, 3:801-830, Nov 2014. URL: https://doi.org/10.3390/biology3040801, doi:10.3390/biology3040801. This article has 184 citations.
(agarwal2007functionalcharacterizationof pages 6-7): Anil K Agarwal, Suja Sukumaran, Rene Bartz, Robert I Barnes, and Abhimanyu Garg. Functional characterization of human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 9: cloning, tissue distribution, gene structure, and enzymatic activity. Journal of Endocrinology, 193:445-457, Jun 2007. URL: https://doi.org/10.1677/joe-07-0027, doi:10.1677/joe-07-0027. This article has 61 citations and is from a peer-reviewed journal.
(kim2023intrinsicandextrinsic pages 9-11): Euri S. Kim, Jennifer G. Casey, Brian S. Tao, Arian Mansur, Nishanthi Mathiyalagan, E. Diane Wallace, Brandie M. Ehrmann, and Vandana A. Gupta. Intrinsic and extrinsic regulation of rhabdomyolysis susceptibility by tango2. Disease Models & Mechanisms, Sep 2023. URL: https://doi.org/10.1242/dmm.050092, doi:10.1242/dmm.050092. This article has 14 citations and is from a domain leading peer-reviewed journal.
(sukumaran2009functionalcharacterizationof media 4c33d1ff): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(sukumaran2009functionalcharacterizationof media ede781db): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(sukumaran2009functionalcharacterizationof media 3e0cacd3): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.
(sukumaran2009functionalcharacterizationof media 0224c14a): Suja Sukumaran, Robert I Barnes, Abhimanyu Garg, and Anil K Agarwal. Functional characterization of the human 1-acylglycerol-3-phosphate-o-acyltransferase isoform 10/glycerol-3-phosphate acyltransferase isoform 3. Journal of molecular endocrinology, 42 6:469-78, Jun 2009. URL: https://doi.org/10.1677/jme-09-0010, doi:10.1677/jme-09-0010. This article has 66 citations and is from a peer-reviewed journal.