Calcineurin-dependent growth of an FK506- and CsA-hypersensitive mutant of Saccharomyces cerevisiae

Parent, Stephen A.; Nielsen, Jennifer; Morin, Nancy R.; Chrebet, Gary; Ramadan, Naasa; Dahl, Arlene M.; Hsu, Ming-Jo; Bostian, Keith A.; Foor, Forrest

doi:10.1099/00221287-139-12-2973

Cited by 66 publications

(57 citation statements)

References 21 publications

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“…FK506 was added to one portion at a final concentration of 1 g/ml. Previous work has shown that the growth of wild-type cells is unaffected by this concentration of FK506, while the growth of the fks1 mutant strain is eventually inhibited (62). Logarithmic growth continued for 2 h after the addition of drug, at which time samples were removed for the isolation of total RNA.…”

Section: Resultsmentioning

confidence: 99%

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Differential Expression and Function of Two Homologous Subunits of Yeast 1,3-β-D-Glucan Synthase

Mazur

Morin

Baginsky

et al. 1995

Molecular and Cellular Biology

396

461

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1,3-␤-D-Glucan is a major structural polymer of yeast and fungal cell walls and is synthesized from UDP-glucose by the multisubunit enzyme 1,3-␤-D-glucan synthase. Previous work has shown that the FKS1 gene encodes a 215-kDa integral membrane protein (Fks1p) which mediates sensitivity to the echinocandin class of antifungal glucan synthase inhibitors and is a subunit of this enzyme. We have cloned and sequenced FKS2, a homolog of FKS1 encoding a 217-kDa integral membrane protein (Fks2p) which is 88% identical to Fks1p. The residual glucan synthase activity present in strains with deletions of fks1 is (i) immunodepleted by antibodies prepared against FKS2 peptides, demonstrating that Fks2p is also a component of the enzyme, and (ii) more sensitive to the echinocandin L-733,560, explaining the increased sensitivity of fks1 null mutants to this drug. Simultaneous disruption of FKS1 and FKS2 is lethal, suggesting that Fks1p and Fks2p are alternative subunits with essential overlapping function. Analysis of FKS1 and FKS2 expression reveals that transcription of FKS1 is regulated in the cell cycle and predominates during growth on glucose, while FKS2 is expressed in the absence of glucose. FKS2 is essential for sporulation, a process which occurs during nutritional starvation. FKS2 is induced by the addition of Ca 2؉ to the growth medium, and this induction is completely dependent on the Ca 2؉ /calmodulin-dependent phosphoprotein phosphatase calcineurin. We have previously shown that growth of fks1 null mutants is highly sensitive to the calcineurin inhibitors FK506 and cyclosporin A. Expression of FKS2 from the heterologous ADH1 promoter results in FK506-resistant growth. Thus, the sensitivity of fks1 mutants to these drugs can be explained by the calcineurin-dependent transcription of FKS2. Moreover, FKS2 is also highly induced in response to pheromone in a calcineurin-dependent manner, suggesting that FKS2 may also play a role in the remodeling of the cell wall during the mating process.The cell wall of Saccharomyces cerevisiae is essential for the integrity and shape of the cell and is a highly dynamic structure the composition and architecture of which vary widely depending upon the composition of the growth medium and the stage of the cell cycle (41). In addition, when haploid cells encounter pheromone of the opposite mating type, the cells transiently arrest in the G 1 phase of the cell cycle and develop an elongated projection requiring new cell wall synthesis (12). Furthermore, diploid cells which are nutritionally starved undergo meiosis and sporulation, a process requiring the formation of new cell wall around the developing spores (reviewed in reference 42).An important component of each of these cell wall types is the glucose polymer 1,3-␤-D-glucan (10, 38, 41). 1,3-␤-D-Glucan synthase (UDP-glucose:1,3-␤-D-glucan 3-␤-D-glucosyltransferase; EC 2.4.1.34) is a membrane enzyme activated by GTP which has been fractionated into soluble (GTP-binding) and membrane-bound (catalytic) components (39, 53). Members of...

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Section: Resultsmentioning

confidence: 99%

“…Previous work has shown that null mutations in FKS1 result in FK506-hypersensitive and Ca 2ϩ -responsive growth (18,21,62). FK506 is a potent inhibitor of the Ca 2ϩ /calmodulin-dependent phosphoprotein phosphatase calcineurin (62).…”

Section: Resultsmentioning

confidence: 99%

Differential Expression and Function of Two Homologous Subunits of Yeast 1,3-β-D-Glucan Synthase

Mazur

Morin

Baginsky

et al. 1995

Molecular and Cellular Biology

396

461

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“…Yeast calcineurin is inhibited by the immunosuppressant components FK506 and CsA [52]. Recently, an FK506-and CsA-hypersensitive mutant 0rksl) was isolated, which was synthetically lethal with calcineurin mutants [53]. Cloning of FKS1 showed that the gene was identical to CWH53 (F. Foor, pers.…”

Section: Discussionmentioning

confidence: 99%

Identification of two cell cycle regulated genes affecting the β1,3‐glucan content of cell walls in Saccharomyces cerevisiae

et al. 1995

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The Calcofluor white-hypersensitive mutants cwh52 and cwh53 are severely reduced in/]l,3-glucan. CWH52 was equivalent to GAS1. CWH53 represented a new gene, located on the right arm of chromosone XII, and predicted to encode a 215 kDa protein with multiple transmembrane domains. The transcription of CWH53 was cell cycle-dependent and, similar to GASll CWH52, increased in late G~, indicating that the formation of /$-glucan is cell cycle-regulated. Further, in some mutant alleles of both gasl/cwh52 and cwh53 lethal concentrations of Calcofluor induced growth arrest at a specific phase of the cell cycle.

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“…These preparations were enriched in the product of the FKS1 gene, which, together with its homologue, FKS2 (126), has been implicated in the activity of glucan synthase (127,128). Mutants in FKS1 were first isolated in a screen for hypersensitivity to immunosuppressants (129), and again, under the name etg1, in a screen for strains resistant to glucan synthase inhibitors (127). Null ( f ks1 ) mutants show a decrease in glucan synthase activity (128) and in incorporation of glucose into β (1 → 3)glucan in vivo (130); double null ( f ks1 f ks2 ) mutants are inviable (126).…”

Section: On the Nature Of The Direct Target Of Rho1 In The Glucan Synmentioning

confidence: 99%

Role of Small G Proteins in Yeast Cell Polarization and Wall Biosynthesis

Cabib

Drgonová

Drgon

1998

Annu. Rev. Biochem.

176

136

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In the vegetative (mitotic) cycle and during sexual conjugation, yeast cells display polarized growth, giving rise to a bud or to a mating projection, respectively. In both cases one can distinguish three steps in these processes: choice of a growth site, organization of the growth site, and actual growth and morphogenesis. In all three steps, small GTP-binding proteins (G proteins) and their regulators play essential signaling functions. For the choice of a bud site, Bud1, a small G protein, Bud2, a negative regulator of Bud1, and Bud5, an activator, are all required. If any of them is defective, the cell loses its ability to select a proper bud position and buds randomly. In the organization of the bud site or of the site in which a mating projection appears, Cdc42, its activator Cdc24, and its negative regulators play a fundamental role. In the absence of Cdc42 or Cdc24, the actin cytoskeleton does not become organized and budding does not take place. Finally, another small G protein, Rho1, is required for activity of β(1 → 3)glucan synthase, the enzyme that catalyzes the synthesis of the major structural component of the yeast cell wall. In all of the above processes, G proteins can work as molecular switches because of their ability to shift between an active GTP-bound state and an inactive GDP-bound state.

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Calcineurin-dependent growth of an FK506- and CsA-hypersensitive mutant of Saccharomyces cerevisiae

Cited by 66 publications

References 21 publications

Differential Expression and Function of Two Homologous Subunits of Yeast 1,3-β-D-Glucan Synthase

Differential Expression and Function of Two Homologous Subunits of Yeast 1,3-β-D-Glucan Synthase

Identification of two cell cycle regulated genes affecting the β1,3‐glucan content of cell walls in Saccharomyces cerevisiae

Role of Small G Proteins in Yeast Cell Polarization and Wall Biosynthesis

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