PSA1 BASIC INFORMATION
| Standard Name | PSA1 1 |
|---|---|
| Systematic Name | YDL055C |
| Alias | MPG1 , VIG9 , SRB1 |
| Feature Type | ORF, Verified |
| Description | GDP-mannose pyrophosphorylase (mannose-1-phosphate guanyltransferase), synthesizes GDP-mannose from GTP and mannose-1-phosphate in cell wall biosynthesis; required for normal cell wall structure (2, 3 and see Summary Paragraph)
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| GO Annotations | All PSA1 GO evidence and references |
|---|---|
| View Computational GO annotations for PSA1 | |
| Molecular Function | |
| Manually curated | |
| Biological Process | |
| Manually curated | |
| Cellular Component | |
| High-throughput |
| Pathways |
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| Mutant Phenotype | All PSA1 Phenotype details and references |
|---|---|
| Classical genetics | |
| null | |
| Large-scale survey | |
| null |
| Interactions | PSA1 All interactions details and references |
|---|---|
| 107 total interaction(s) for 90 unique genes/features. | |
| Physical Interactions |
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| Genetic Interactions |
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| External Links | All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | UniProtKB |
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| Primary SGDID | S000002213 |
|---|
ADDITIONAL INFORMATION for PSA1
SUMMARY PARAGRAPH for PSA1
PSA1 encodes GDP-Man pyrophosphorylase (EC 2.7.7.13) (2, 4), which synthesizes GDP-mannose from mannose-1-phosphate and GTP. This is a necessary step in the preparation of mannose for incorporation into N-linked and O-linked glycoproteins, and psa1 mutants exhibit defects in both processes (2). In this pathway, Psa1p lies downstream of Sec53p and upstream of Dpm1p. Deletion of PSA1 is lethal (2, 5), but hypomorphic mutants exhibit a variety of phenotypes indicating a defect in cell wall biosynthesis. Specifically, psa1 mutants are sensitive to hypoosmolarity and require sorbitol in their growth medium (3); they are also unable to mate (3), hypersensitive to the drug geneticin (G418) (2), inefficiently transformed by electroporation or lithium acetate (3), and they leak cell surface proteins into the surrounding medium (3).
PSA1 was cloned as a multicopy suppressor (plasmid suppressor of alg1) that partially restored viability to an alg1 mutant strain in a cln1 cln2 background (5). PSA1 expression appears to be cell-cycle regulated, with transcription patterns similar to those of CLN2 and increasing 4-6x near the start of the cell cycle (5). PSA1 has been independently identified in several mutant screens and thus has multiple aliases, including VIG9 (vanadate-resistant and immature glycosylation) (2), SRB1 (requires sorbitol) (3, 6), and MPG1 (mannose-1-phosphate guanyltransferase) (4). The null phenotype is complemented by introduction of the Candida albicans (7, 8), Candida glabrata (8), or Kluyveromyces lactis (9) homologs.
REFERENCES CITED ON THIS PAGE [View Complete Literature Guide for PSA1]
| 1) | Schultz, J. and G.F. Sprague (1995) Isolation of the gene encoding mannose-1-phosphate guanyltransferase from yeast. Unpublished |
| 2) | Hashimoto H, et al. (1997) Saccharomyces cerevisiae VIG9 encodes GDP-mannose pyrophosphorylase, which is essential for protein glycosylation. J Biol Chem 272(26):16308-14 |
| 3) | Yoda K, et al. (2000) Defect in cell wall integrity of the yeast saccharomyces cerevisiae caused by a mutation of the GDP-mannose pyrophosphorylase gene VIG9. Biosci Biotechnol Biochem 64(9):1937-41 |
| 4) | Kruszewska JS, et al. (1998) Isolation of a Trichoderma reesei cDNA encoding GTP: a-D-mannose-1-phosphate guanyltransferase involved in early steps of protein glycosylation. Curr Genet 33(6):445-50 |
| 5) | Benton BK, et al. (1996) Over-expression of S. cerevisiae G1 cyclins restores the viability of alg1 N-glycosylation mutants. Curr Genet 29(2):106-13 |
| 6) | Stateva LI, et al. (1991) Cloning and characterization of a gene which determines osmotic stability in Saccharomyces cerevisiae. Mol Cell Biol 11(8):4235-43 |
| 7) | Warit S, et al. (1998) Cloning and sequencing of the Candida albicans homologue of SRB1/PSA1/VIG9, the essential gene encoding GDP-mannose pyrophosphorylase in Saccharomyces cerevisiae. Microbiology 144 ( Pt 9):2417-26 |
| 8) | Ohta A, et al. (2000) The VIG9 gene products from the human pathogenic fungi Candida albicans and Candida glabrata encode GDP-mannose pyrophosphorylase. Biochim Biophys Acta 1475(3):265-72 |
| 9) | Uccelletti D, et al. (2005) Enhanced secretion of heterologous proteins in Kluyveromyces lactis by overexpression of the GDP-mannose pyrophosphorylase, KlPsa1p. FEMS Yeast Res 5(8):735-46 |




