AYR1 encodes NADPH-dependent 1-acyldihydroxyacetone-phosphate reductase (ADR; EC 1.1.1.101), a short-chain dehydrogenase/reductase (SDR) family enzyme that reduces 1-acyl-dihydroxyacetone phosphate (acyl-DHAP) to 1-acyl-sn-glycerol 3-phosphate (lysophosphatidic acid). This is the second step of the dihydroxyacetone-phosphate route to phosphatidic acid, linking the dual-specificity G3P/DHAP acyltransferases Gpt2/Gat1 and Sct1/Gat2 to the lysophosphatidate acyltransferases (Slc1, Ale1). Ayr1 is a constitutive lipid droplet protein that is also present in the endoplasmic reticulum and, by fractionation, in the mitochondrial outer membrane. Its deletion abolishes ADR activity in lipid droplets and lowers it about 3-fold in microsomes, implying an additional microsomal ADR; ayr1 spores fail to germinate. Ayr1 has a minor triacylglycerol lipase activity that contributes to triacylglycerol mobilization in the absence of the main lipases Tgl3/Tgl4/Tgl5. When purified and reconstituted, it has also been reported to form an NADPH-stimulated, cation-selective channel in lipid bilayers. Its lipolysis of lipid droplet triacylglycerol is required for starvation-induced autophagy. Deletion of AYR1 alters cell wall synthase activities and cell wall composition, probably indirectly, and Ayr1 provides the reductive 17beta-hydroxysteroid dehydrogenase activity that converts exogenous DHEA to androstenediol in yeast.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | EXP PMID:1512203 The acyl dihydroxyacetone phosphate pathway enzymes for glyc... | ACCEPT | Summary: SGD EXP from Racenis et al. 1992, which first detected NADPH-specific acyl/alkyl-DHAP reductase (EC 1.1.1.101) activity in total yeast membranes. The study predates gene identification, but the activity it measured was later shown to be encoded by AYR1 (deletion and E. coli expression). Reason: Activity is the defining catalytic function of Ayr1; the curator linked the 1992 biochemistry to the gene, consistent with the 2000 genetic identification. Supporting Evidence: PMID:1512203 Total membrane fraction of S. cerevisiae also exhibited acyl/alkyl DHAP reductase (EC 1.1.1.101) activity, which has not been reported previously. PMID:10617610 Heterologous expression of Ayr1p in Escherichia coli resulted in gain of ADR activity in the prokaryote, confirming that YIL124w is the structural gene of the enzyme |
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for acylglycerone-phosphate reductase activity, placed at an SDR node whose experimental grounding is Ayr1 itself (SGD:S000001386 in with/from), which is expected for the reference member. Reason: Correct core activity; the IBA adds that the activity is inherited within this SDR clade. Supporting Evidence: PMID:10617610 Heterologous expression of Ayr1p in Escherichia coli resulted in gain of ADR activity in the prokaryote, confirming that YIL124w is the structural gene of the enzyme |
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | IEA GO_REF:0000120 | ACCEPT | Summary: IEA from RHEA/EC 1.1.1.101 mapping (GO_REF:0000120) derived from the UniProt catalytic-activity annotation for Ayr1. Correct for this protein. Supporting Evidence: file:yeast/AYR1/AYR1-uniprot.txt Reaction=a 1-acylglycerone 3-phosphate + NADPH + H(+) = a 1-acyl-sn- |
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | IMP PMID:10617610 1-Acyldihydroxyacetone-phosphate reductase (Ayr1p) of the ye... | ACCEPT | Summary: IMP from Athenstaedt and Daum 2000; ayr1 deletion abolished ADR activity of lipid particles and reduced microsomal ADR ~3-fold; heterologous expression in E. coli conferred ADR activity. Supporting Evidence: PMID:10617610 Deletion of the open reading frame YIL124w (in the following named AYR1) abolished reduction of 1-acyldihydroxyacetone phosphate in lipid particles PMID:10617610 Heterologous expression of Ayr1p in Escherichia coli resulted in gain of ADR activity in the prokaryote, confirming that YIL124w is the structural gene of the enzyme |
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (PWY3O-6407, phosphatidate biosynthesis I, DHAP pathway) assigning the acyl-DHAP + NADPH -> 1-acyl-G3P step (EC 1.1.1.101) to Ayr1. This is exactly Ayr1's characterised reaction. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. PMID:10617610 Deletion of the open reading frame YIL124w (in the following named AYR1) abolished reduction of 1-acyldihydroxyacetone phosphate in lipid particles |
| GO:0000140 acylglycerone-phosphate reductase (NADP+) activity | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA from the phosphatidate biosynthesis superpathway (PWY3O-6635) for the same EC 1.1.1.101 step; correct for Ayr1. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. |
| GO:0004806 triacylglycerol lipase activity | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: PAINT IBA for triacylglycerol lipase activity at an SDR node grounded only in Ayr1's own experimental annotation (24187129). Ayr1 is a short-chain dehydrogenase/reductase, not a canonical alpha/beta-hydrolase lipase; the lipase activity is minor. Reason: The Ayr1 lipase activity is experimentally supported but quantitatively minor relative to Tgl3/Tgl4; retain as a secondary activity rather than a core function. Clade-wide inheritance of lipase activity among SDR relatives is not established by other family members. Supporting Evidence: PMID:24187129 These investigations led to the identification of Ayr1p as a novel triacylglycerol lipase of yeast lipid droplets PMID:24187129 TG turnover is not only catalyzed by the main lipases Tgl3p, Tgl4p, and Tgl5p but is also performed by a subset of lipases and hydrolases with lower activities |
| GO:0004806 triacylglycerol lipase activity | IDA PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IDA from Ploier et al. 2013 (inhibitor-based functional proteomics and in vitro assays) identifying Ayr1 as a novel TAG lipase of lipid droplets. Reason: Real but secondary activity; Ayr1 is one of several low-activity hydrolases that contribute to TAG turnover in the absence of Tgl3/4/5. Supporting Evidence: PMID:24187129 These investigations led to the identification of Ayr1p as a novel triacylglycerol lipase of yeast lipid droplets PMID:24187129 TG turnover is not only catalyzed by the main lipases Tgl3p, Tgl4p, and Tgl5p but is also performed by a subset of lipases and hydrolases with lower activities |
| GO:0004806 triacylglycerol lipase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: IEA from RHEA/EC 3.1.1.3 mapping derived from UniProt's catalytic-activity line, which itself rests on PMID:24187129. Reason: Consistent with the experimental data but describes a secondary activity of Ayr1. Supporting Evidence: PMID:24187129 These investigations led to the identification of Ayr1p as a novel triacylglycerol lipase of yeast lipid droplets |
| GO:0004806 triacylglycerol lipase activity | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 where AYR1 was analysed in combination with deletion of the main TAG lipases (Tgl3/Tgl4/Tgl5; with/from SGD ids). In the lipase-deficient background, Ayr1 overexpression promoted TAG mobilisation. Reason: Supports a contributory TAG lipase activity, but even with AYR1 deleted in the tgl3/4/5 background TAG was still mobilised, so Ayr1 is a minor lipase. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0004806 triacylglycerol lipase activity | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 where AYR1 was analysed in combination with deletion of the main TAG lipases (Tgl3/Tgl4/Tgl5; with/from SGD ids). In the lipase-deficient background, Ayr1 overexpression promoted TAG mobilisation. Reason: Supports a contributory TAG lipase activity, but even with AYR1 deleted in the tgl3/4/5 background TAG was still mobilised, so Ayr1 is a minor lipase. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0004806 triacylglycerol lipase activity | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 where AYR1 was analysed in combination with deletion of the main TAG lipases (Tgl3/Tgl4/Tgl5; with/from SGD ids). In the lipase-deficient background, Ayr1 overexpression promoted TAG mobilisation. Reason: Supports a contributory TAG lipase activity, but even with AYR1 deleted in the tgl3/4/5 background TAG was still mobilised, so Ayr1 is a minor lipase. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0004806 triacylglycerol lipase activity | IMP PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IMP from Ploier et al. 2013 supporting TAG lipase activity of Ayr1. Reason: Secondary activity; see other lipase rows. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells |
| GO:0005737 cytoplasm | HDA PMID:11914276 Subcellular localization of the yeast proteome. | KEEP AS NON CORE | Summary: HDA from the Kumar et al. 2002 genome-wide immunolocalization survey scoring Ayr1 as cytoplasmic. Reason: Coarse but not wrong (ER and lipid droplets are within the cytoplasm); lipid droplet and ER are the informative locations. Supporting Evidence: PMID:11914276 By high-throughput immunolocalization of tagged gene products, we have determined the subcellular localization of 2744 yeast proteins. |
| GO:0005739 mitochondrion | HDA PMID:14576278 The proteome of Saccharomyces cerevisiae mitochondria. | KEEP AS NON CORE | Summary: HDA from the Sickmann et al. 2003 mitochondrial proteome detecting Ayr1 in purified mitochondria. Reason: Consistent with later fractionation placing Ayr1 in the mitochondrial outer membrane, possibly at ER-mitochondria contacts; no mitochondrial ADR role is defined, so non-core. Supporting Evidence: PMID:14576278 The proteins of highly pure yeast mitochondria were separated by several independent methods and analyzed by tandem MS. PMID:28916712 Upon cellular fractionation, Ayr1 was present in both mitochondrial and microsomal fractions |
| GO:0005739 mitochondrion | HDA PMID:16823961 Toward the complete yeast mitochondrial proteome: multidimen... | KEEP AS NON CORE | Summary: HDA from the PROMITO multidimensional mitochondrial proteome (Reinders et al. 2006). Reason: Proteomic detection of Ayr1 in mitochondria; non-core location. Supporting Evidence: PMID:16823961 A total of 851 different proteins (PROMITO dataset) were identified |
| GO:0005739 mitochondrion | HDA PMID:24769239 Quantitative variations of the mitochondrial proteome and ph... | KEEP AS NON CORE | Summary: HDA from the quantitative mitochondrial proteome/phosphoproteome of Renvoise et al. 2014. Reason: Proteomic detection in isolated mitochondria; non-core location. Supporting Evidence: PMID:24769239 we performed an overall quantitative proteomic and phosphoproteomic study of isolated mitochondria |
| GO:0005741 mitochondrial outer membrane | HDA PMID:16407407 Proteomic analysis of the yeast mitochondrial outer membrane... | KEEP AS NON CORE | Summary: HDA from the purified mitochondrial outer membrane proteome (Zahedi et al. 2006). Reason: Supported by later fractionation (Kruger et al. 2017); the same study notes the outer-membrane proteome also captures ER-contact and mis-sorted proteins; non-core location. Supporting Evidence: PMID:16407407 to determine the proteome of highly purified mitochondrial outer membranes PMID:28916712 yet Ayr1 may also be linked to regions of close contact between ER and mitochondria |
| GO:0005741 mitochondrial outer membrane | IDA PMID:28916712 Identification of new channels by systematic analysis of the... | KEEP AS NON CORE | Summary: IDA (is_active_in) from Kruger et al. 2017, who found Ayr1 abundant in the mitochondrial outer membrane fraction and recorded channel activity of the reconstituted protein. Reason: Location supported by fractionation, though the authors themselves allow that Ayr1 may sit at ER-mitochondria contacts. Non-core relative to lipid droplet/ER, where ADR activity is measured. Supporting Evidence: PMID:28916712 Upon cellular fractionation, Ayr1 was present in both mitochondrial and microsomal fractions PMID:28916712 yet Ayr1 may also be linked to regions of close contact between ER and mitochondria |
| GO:0005741 mitochondrial outer membrane | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: IEA from UniProt subcellular location (SL-0172 mitochondrion outer membrane), based on PMID:16407407 and PMID:28916712. Reason: Mirrors the experimental rows; non-core location. Supporting Evidence: PMID:28916712 Upon cellular fractionation, Ayr1 was present in both mitochondrial and microsomal fractions |
| GO:0005783 endoplasmic reticulum | EXP PMID:14562095 Global analysis of protein localization in budding yeast. | ACCEPT | Summary: SGD EXP from the Huh et al. 2003 GFP-fusion survey placing Ayr1 in the ER. Supporting Evidence: PMID:14562095 expressing full-length, chromosomally tagged green fluorescent protein fusion proteins PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005783 endoplasmic reticulum | EXP PMID:28916712 Identification of new channels by systematic analysis of the... | ACCEPT | Summary: SGD EXP from Kruger et al. 2017; Ayr1 co-fractionated with microsomes as well as mitochondria. Supporting Evidence: PMID:28916712 Upon cellular fractionation, Ayr1 was present in both mitochondrial and microsomal fractions |
| GO:0005783 endoplasmic reticulum | HDA PMID:26928762 One library to make them all: streamlining the creation of y... | ACCEPT | Summary: HDA from the SWAT N-terminal GFP library of endomembrane proteins (Yofe et al. 2016) placing Ayr1 in the ER. Supporting Evidence: PMID:26928762 carrying SWAT-GFP modules at the amino termini of endomembrane proteins PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005783 endoplasmic reticulum | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA (is_active_in ER) from PTN001213826; consistent with microsomal ADR activity of Ayr1. Supporting Evidence: PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005783 endoplasmic reticulum | IDA PMID:10617610 1-Acyldihydroxyacetone-phosphate reductase (Ayr1p) of the ye... | ACCEPT | Summary: IDA from Athenstaedt and Daum 2000; Ayr1 detected immunologically in microsomes, and microsomal ADR activity drops in ayr1 cells. Supporting Evidence: PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005783 endoplasmic reticulum | IEA GO_REF:0000044 | ACCEPT | Summary: IEA from UniProt subcellular location (SL-0095 endoplasmic reticulum). Correct. Supporting Evidence: PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005811 lipid droplet | EXP PMID:10515935 Identification and characterization of major lipid particle ... | ACCEPT | Summary: SGD EXP from Athenstaedt et al. 1999, which identified the YIL124w product among major lipid particle proteins by mass spectrometry. Supporting Evidence: PMID:10515935 Some proteins or their polypeptide fragments were identified in several bands, namely Fat1p, Tgl1p, Erg6p, and the gene product of YIL124w |
| GO:0005811 lipid droplet | EXP PMID:21820081 Lipid particles/droplets of the yeast Saccharomyces cerevisi... | ACCEPT | Summary: SGD EXP from the lipid particle lipidome/proteome study of Grillitsch et al. 2011, which lists Ayr1 among LP proteins. Supporting Evidence: PMID:21820081 namely the dihydroxyacetone phosphate acyltransferase Ayr1p |
| GO:0005811 lipid droplet | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA (is_active_in lipid droplet); Ayr1 is the experimentally grounded member and ADR activity is measured in isolated lipid particles. Supporting Evidence: PMID:10617610 Deletion of the open reading frame YIL124w (in the following named AYR1) abolished reduction of 1-acyldihydroxyacetone phosphate in lipid particles |
| GO:0005811 lipid droplet | IDA PMID:10617610 1-Acyldihydroxyacetone-phosphate reductase (Ayr1p) of the ye... | ACCEPT | Summary: IDA from Athenstaedt and Daum 2000 showing Ayr1 as a major lipid particle component carrying ADR activity. Supporting Evidence: PMID:10617610 Deletion of the open reading frame YIL124w (in the following named AYR1) abolished reduction of 1-acyldihydroxyacetone phosphate in lipid particles PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005811 lipid droplet | IDA PMID:24868093 High confidence proteomic analysis of yeast LDs identifies a... | ACCEPT | Summary: IDA from Currie et al. 2014 protein-correlation profiling; Ayr1 is one of twelve constitutive LD proteins found in all proteomes. Supporting Evidence: PMID:24868093 The twelve proteins identified in all proteomes (Ayr1, Eht1, Erg1, Erg6, Erg7, Faa1, Faa4, Fat1, Pet10, Slc1, Tgl1, and Tgl3) are likely to be constitutive LD proteins |
| GO:0005811 lipid droplet | IEA GO_REF:0000044 | ACCEPT | Summary: IEA from UniProt subcellular location (SL-0154 lipid droplet). Correct. Supporting Evidence: file:yeast/AYR1/AYR1-uniprot.txt SUBCELLULAR LOCATION: Lipid droplet |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: YeastPathways RCA placing the DHAP-pathway reductase step in the cytosol (PWY3O-6407 / PWY3O-6635). Ayr1 is a lipid droplet and ER (and outer mitochondrial membrane) protein whose ADR activity is measured in lipid particle and microsomal fractions. Reason: The cytosol location is a pathway-level default rather than an observation about Ayr1; the protein acts on membrane-embedded acyl-DHAP at organelle surfaces, already captured by lipid droplet and ER annotations. Supporting Evidence: PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: YeastPathways RCA placing the DHAP-pathway reductase step in the cytosol (PWY3O-6407 / PWY3O-6635). Ayr1 is a lipid droplet and ER (and outer mitochondrial membrane) protein whose ADR activity is measured in lipid particle and microsomal fractions. Reason: The cytosol location is a pathway-level default rather than an observation about Ayr1; the protein acts on membrane-embedded acyl-DHAP at organelle surfaces, already captured by lipid droplet and ER annotations. Supporting Evidence: PMID:10617610 both lipid particles and microsomes harbor Ayr1p, which was confirmed by immunological detection of the protein in these two cellular compartments |
| GO:0006654 phosphatidic acid biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for phosphatidic acid biosynthetic process; Ayr1 produces lysophosphatidate, the direct precursor of PA, in the DHAP pathway. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. |
| GO:0006654 phosphatidic acid biosynthetic process | IMP PMID:10617610 1-Acyldihydroxyacetone-phosphate reductase (Ayr1p) of the ye... | ACCEPT | Summary: IMP from Athenstaedt and Daum 2000; ayr1 deletion abolishes lipid-particle ADR activity in the DHAP route to phosphatidic acid. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. PMID:10617610 Deletion of the open reading frame YIL124w (in the following named AYR1) abolished reduction of 1-acyldihydroxyacetone phosphate in lipid particles |
| GO:0006654 phosphatidic acid biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (superpathway of phosphatidate biosynthesis, PWY3O-6635); Ayr1 catalyses the reductase step. Correct. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. |
| GO:0008654 phospholipid biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (PWY3O-6407) for phospholipid biosynthetic process. Phosphatidic acid synthesis is a phospholipid biosynthetic process and Ayr1 catalyses one of its steps; the more specific GO:0006654 is also annotated. Supporting Evidence: PMID:10617610 Biosynthesis of phosphatidic acid through the dihydroxyacetone phosphate pathway requires NADPH-dependent reduction of the intermediate 1-acyldihydroxyacetone phosphate before the second step of acylation. PMID:1512203 indicates that non-ether glycerolipids are synthesized in this organism via the acyl DHAP pathway |
| GO:0019433 triglyceride catabolic process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: PAINT IBA for triglyceride catabolic process at the same SDR node, grounded only in Ayr1's own 2013 lipase data. Reason: Ayr1 contributes to TAG mobilisation as a minor lipase; non-core relative to its ADR role. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0019433 triglyceride catabolic process | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 for triglyceride catabolic process with the main TAG lipases Tgl3/Tgl4/Tgl5 (with/from). Reason: Ayr1 has a measurable but minor role in TAG mobilisation, revealed mainly in a lipase-deficient background. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0019433 triglyceride catabolic process | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 for triglyceride catabolic process with the main TAG lipases Tgl3/Tgl4/Tgl5 (with/from). Reason: Ayr1 has a measurable but minor role in TAG mobilisation, revealed mainly in a lipase-deficient background. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0019433 triglyceride catabolic process | IGI PMID:24187129 Screening for hydrolytic enzymes reveals Ayr1p as a novel tr... | KEEP AS NON CORE | Summary: IGI rows from Ploier et al. 2013 for triglyceride catabolic process with the main TAG lipases Tgl3/Tgl4/Tgl5 (with/from). Reason: Ayr1 has a measurable but minor role in TAG mobilisation, revealed mainly in a lipase-deficient background. Supporting Evidence: PMID:24187129 In vivo mobilization of TG by Lpx1p and Ayr1p confirmed the role of these two proteins as lipases in living cells PMID:24187129 Interestingly, a yeast strain lacking not only in the major lipases Tgl3p, Tgl4p, and Tgl5p but also Ayr1p, Lpx1p, or Ldh1p, respectively, still showed mobilization of TG. |
| GO:0022834 ligand-gated channel activity | IDA PMID:28916712 Identification of new channels by systematic analysis of the... | KEEP AS NON CORE | Summary: IDA from Kruger et al. 2017; purified Ayr1 reconstituted in planar bilayers gave a cation-selective channel whose gating was stimulated by NADPH (abolished by mutating the Rossmann-fold glycines), but not by the substrate acyl-DHAP. Reason: Experimental annotation from a single electrophysiology study; it has not been independently confirmed, and a physiological transport role is not known. Retain as non-core rather than overrule the curator. Supporting Evidence: PMID:28916712 We conclude that Ayr1 forms a cation-selective channel that is stimulated by NADPH. |
| GO:0055085 transmembrane transport | IEA GO_REF:0000108 | KEEP AS NON CORE | Summary: IEA (GO_REF:0000108) inferring transmembrane transport from the ligand-gated channel activity annotation. Reason: Follows logically from the channel MF row; equally tentative and non-core. Supporting Evidence: PMID:28916712 We conclude that Ayr1 forms a cation-selective channel that is stimulated by NADPH. |
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Download this section (compressed HTML)Q: Which enzyme supplies the residual (about one third) microsomal acyl-DHAP reductase activity in ayr1 cells, and how much of cellular phosphatidate flux passes through the DHAP route versus direct glycerol-3-phosphate acylation?
Q: Is the NADPH-stimulated channel activity reported for reconstituted Ayr1 physiologically relevant in the mitochondrial outer membrane, or is it a property of the purified SDR in bilayers?
Experiment: Quantify 13C-glycerol versus 13C-DHAP incorporation into lysophosphatidate and PA in wild type, ayr1, and ayr1 with candidate microsomal SDR deletions.
Hypothesis: A second microsomal reductase accounts for residual ADR activity, and the DHAP route carries a substantial share of de novo PA synthesis.
Type: metabolic labelling/genetics
Bifunctional triacylglycerol lipase and 1-acyl DHAP reductase; NADPH-dependent 1-acyl dihydroxyacetone phosphate reductase involved in phosphatidic acid biosynthesis; lipid droplet triacylglycerol lipase involved in mobilization of non-polar lipids; found in lipid particles, endoplasmic reticulum and mitochondrial outer membrane; forms NADPH-regulated channel in mitochondrial outer membrane; required for spore germination; role in cell wall biosynthesis; capable of metabolizing steroid hormones
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Download this section (compressed HTML)Loading supporting content…
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