Table 1 . Glycerolipid synthesis enzymes.
| Gene | Ino− or Opi− phenotype | Enzyme | Mol mass (kDa) | Isoelectric point | Molecules per cellb | Locationc | Transmembrane domains | Phosphorylation sitesd |
|---|---|---|---|---|---|---|---|---|
| SCT1 (GAT2) | Ino− | Glycerol-3-P /dihydroxyacetone-P acyltransferase | 85.7 | 7.27 | 1050 | ER | 4 | Few |
| GPT2 (GAT1) | — | Glycerol-3-P /dihydroxyacetone-P acyltransferase | 83.6 | 10.3 | 3100 | ER, lipid droplets | 4 | Several |
| AYR1 | — | Acyl DHAP reductase | 32.8 | 9.92 | 3670 | ER, lipid droplets | None | None |
| SLC1 | — | LysoPA/Acylglycerol-3-P acyltransferase | 33.8 | 10.41 | ND | ER, lipid droplets | 1 | None |
| ALE1 (SLC4,LPT1,LCA1) | — | LysoPA/Acylglycerol-3-P acyltransferase | 72.2 | 10.3 | ND | ER | 7 | Several |
| PSI1 (CST26) | — | LysoPI acyltransferase | 45.5 | 10.15 | 2010 | ER | 4 | None |
| TAZ1 | — | LysoPC acyltransferase/ monolysoCL acyltransferase | 44.2 | 9.38 | 1340 | Mitochondria | None | None |
| CDS1 (CDG1)a | Opi− | CDP-DAG synthase | 51.8 | 8.64 | ND | ER, mitochondria | 6 | Few |
| CHO1 (PSS1)a | Opi− | PS synthase | 30.8 | 6.23 | ND | ER | 2 | Several |
| PSD1a | Opi− | PS decarboxylase | 56.6 | 9.84 | 1080 | Mitochondria | None | None |
| PSD2 | — | PS decarboxylase | 130 | 7.85 | ND | Vacuole, endomembranes | None | Few |
| CHO2 (PEM1)a | Opi− | PE methyltransferase | 101.2 | 8.56 | 1810 | ER | 8 | Few |
| OPI3 (PEM2)a | Opi− | Phospholipid methyltransferase | 23.1 | 9.6 | 5890 | ER, mitochondria | None | None |
| PAH1 (SMP2) | — | PA phosphatase | 95 | 4.68 | 3910 | Cytoplasm, ER | None | Several |
| DGK1 (HSD1) | — | DAG kinase | 32.8 | 9.48 | 784 | ER | 4 | Few |
| EKI1a | — | Ethanolamine kinase | 61.6 | 5.69 | 3420 | Cytoplasm | None | Few |
| ECT1 (MUQ1) | — | Ethanolamine-P cytidylyltransferase | 36.8 | 6.44 | 4700 | Cytoplasm | None | None |
| EPT1a | — | Ethanolamine/choline phosphotransferase | 44.5 | 6.5 | ND | ER | 7 | None |
| CKI1a | — | Choline kinase | 66.3 | 5.43 | 3930 | Cytoplasm | None | Several |
| PCT1 (CCT1,BSR2)a | Opi− | Choline-P cytidylyltransferase | 49.4 | 9.26 | 3050 | Cytoplasm, nucleus | None | Several |
| CPT1a | — | Choline phosphotransferase | 44.8 | 6.57 | 981 | Membrane | 8 | None |
| PGS1 (PEL1) | — | PGP synthase | 59.3 | 10.5 | ND | Mitochondria | None | None |
| GEP4 | — | PGP phosphatase | 20.9 | 9.18 | ND | Mitochondria | None | None |
| CRD1 (CLS1) | — | CL synthase | 32 | 10.55 | 876 | Mitochondria | 3 | None |
| PIS1 | Ino− | PI synthase | 24.8 | 8.92 | 3810 | ER | 3 | None |
| LSB6 | — | PI 4-kinase | 70.2 | 6.68 | 57 | Plasma membrane, vacuole membrane | None | None |
| STT4 | Ino− | PI 4-kinase | 214.6 | 7.44 | 846 | Plasma membrane | None | Few |
| PIK1 | — | PI 4-kinase | 119.9 | 6.46 | 1600 | Plasma membrane, nucleus, Golgi | None | Several |
| VPS34 (END12,PEP15,VPL7,VPT29,STT8,VPS7) | Opi− | PI 3-kinase | 100.9 | 7.79 | 1080 | Vacuole | None | None |
| MSS4 | Ino− | PI 4-P 5-kinase | 89.3 | 10.13 | ND | Cytoplasm | None | Several |
| FAB1 (SVL7) | Ino− | PI 3-P 5-kinase | 257.4 | 8.45 | 149 | Vacuole | None | Several |
| DGA1a | — | Acyl-CoA diacylglycerol acyltransferase | 47.7 | 10.39 | 907 | ER, lipid droplets | 1 | Few |
| LRO1a | — | Phospholipid diacylglycerol acyltransferase | 75.3 | 6.67 | ND | ER | 1 | Few |
| ARE1 (SAT2)a | — | Acyl-CoA sterol acyltransferase | 71.6 | 8.27 | ND | ER | 9 | Several |
| ARE2 (SAT1)a | — | Acyl-CoA sterol acyltransferase | 74.0 | 7.71 | 279 | ER | 9 | Several |
| Phospholipid synthesis regulatory proteins | ||||||||
| INO2 (DIE1, SCS1)a | Ino− | Transcriptional activator | 34.2 | 6.23 | 784 | Nucleus | None | None |
| INO4 | Ino− | Transcriptional activator | 17.4 | 10.21 | 521 | Nucleus, cytoplasm | None | None |
| OPI1 | Opi− | Transcriptional repressor | 46 | 4.87 | 1280 | Nuclear/ER membrane | None | Few |
Much of the information in the table may be found in the Saccharomyces Genome Database. Ino−, inositol auxotrophy; Opi−, inositol excretion; ND, not determined.
a
Genes containing the UASINO element and regulated by the Ino2-Ino4-Opi1 circuit. The names in parentheses are aliases.