The SIT4 gene, which encodes protein phosphatase 2A, is required for telomere function in Saccharomyces cerevisiae

Hayashi, Nobuyasu; Nomura, Takahiro; Sakumoto, Naoko; Mukai, Yoshihiko; Kaneko, Yoshinobu; Harashima, Satoshi; Murakami, Seishi

doi:10.1007/s00294-005-0577-1

Cited by 18 publications

(17 citation statements)

References 42 publications

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“…In order to characterize the functions of FgPP2A, FgSIT4 and FgPPG1 , we tested whether these genes can complement the yeast sit4 mutant (Hayashi et al ., ). An expression vector pYES2 containing the full‐length FgPP2A, FgSIT4 or FgPPG1 cDNA was transformed into the sit4 mutant, BY4741ΔSIT4.…”

Section: Resultsmentioning

confidence: 97%

The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum

et al. 2014

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Summary The target of rapamycin (TOR) signaling pathway plays critical roles in controlling cell growth in a variety of eukaryotes. However, the contribution of this pathway in regulating virulence of plant pathogenic fungi is unknown. We identified and characterized nine genes encoding components of the TOR pathway in Fusarium graminearum. Biological, genetic and biochemical functions of each component were investigated. The FgFkbp12‐rapamycin complex binds to the FgTor kinase. The type 2A phosphatases FgPp2A, FgSit4 and FgPpg1 were found to interact with FgTap42, a downstream component of FgTor. Among these, we determined that FgPp2A is likely to be essential for F. graminearum survival, and FgSit4 and FgPpg1 play important roles in cell wall integrity by positively regulating the phosphorylation of FgMgv1, a key MAP kinase in the cell wall integrity pathway. In addition, the FgPpg1 interacting protein, FgTip41, is involved in regulating mycelial growth and virulence. Notably, FgTip41 does not interact with FgTap42 but with FgPpg1, suggesting the existence of FgTap42:FgPpg1:FgTip41 heterotrimer in F. graminearum, a complex not observed in the yeast model. Collectively, we defined a genetic regulatory framework that elucidates how the TOR pathway regulates virulence and vegetative development in F. graminearum.

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Section: Resultsmentioning

confidence: 97%

The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum

et al. 2014

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“…VOL. 8,2009 DISTINCT Sit4 COMPLEXES AS ANTIFUNGAL EFFECTORS 1645 mycin (Sit4/Tap42, Sit4/Sap190, and Sit4/Sap155) and potentially in other Sit4 functions related to ion homeostasis, oleate toxicity, or telomere integrity (20,35,39). Paradoxically, we show here that Tap42 binding-deficient sit4 mutants (52) survive zymocin and display Elp1 hyperphosphorylation, both traits typical of sit4⌬ and sap185⌬ sap190⌬ mutants.…”

Section: Discussionmentioning

confidence: 90%

Distinct Subsets of Sit4 Holophosphatases Are Required for Inhibition ofSaccharomyces cerevisiaeGrowth by Rapamycin and Zymocin

et al. 2009

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Protein phosphatase Sit4 is required for growth inhibition of Saccharomyces cerevisiae by the antifungals rapamycin and zymocin. Here, we show that the rapamycin effector Tap42, which interacts with Sit4, is dispensable for zymocin action. Although Tap42 binding-deficient sit4 mutants are resistant to zymocin, these mutations also block interaction between Sit4 and the Sit4-associating proteins Sap185 and Sap190, previously shown to mediate zymocin toxicity. Among the four different SAP genes, we found that SAP190 deletions specifically induce rapamycin resistance but that this phenotype is reversed in the additional absence of SAP155. Similarly, the rapamycin resistance of an rrd1⌬ mutant lacking the Sit4 interactor Rrd1 specifically requires the Sit4/Sap190 complex. Thus, Sit4/Sap190 and Sit4/Sap155 holophosphatases apparently play opposing roles following rapamycin treatment, although rapamycin inhibition is operational in the absence of all Sap family members or Sit4. We further identified a Sit4-interacting region on Sap185 in sap190⌬ cells that mediates Sit4/Sap185 complex formation and is essential for dephosphorylation of Elp1, a subunit of the Elongator complex. This suggests that Sit4/Sap185 and Sit4/Sap190 holophosphatases promote Elongator functions, a notion supported by data showing that their inactivation eliminates Elongator-dependent processes, including tRNA suppression by SUP4 and tRNA cleavage by zymocin.

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“…SIT4 phosphatase-associated protein regulates SIT4 activity in S. cerevisiae , which is required for G1 cyclin transcription and bud formation (Luke et al, 1996). Moreover, cells without SIT4 are deficient in telomere-silencing ability (Hayashi et al, 2005). On the other hand, the Arabidopsis putative orthologous of the identified HECT domain-containing protein is involved in control of endoreplication cycles in trichomes (El Refy et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Unravelling the proteomic profile of rice meiocytes during early meiosis

2014

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Transfer of genetic traits from wild or related species into cultivated rice is nowadays an important aim in rice breeding. Breeders use genetic crosses to introduce desirable genes from exotic germplasms into cultivated rice varieties. However, in many hybrids there is only a low level of pairing (if existing) and recombination at early meiosis between cultivated rice and wild relative chromosomes. With the objective of getting deeper into the knowledge of the proteins involved in early meiosis, when chromosomes associate correctly in pairs and recombine, the proteome of isolated rice meiocytes has been characterized by nLC-MS/MS at every stage of early meiosis (prophase I). Up to 1316 different proteins have been identified in rice isolated meiocytes in early meiosis, being 422 exclusively identified in early prophase I (leptotene, zygotene, or pachytene). The classification of proteins in functional groups showed that 167 were related to chromatin structure and remodeling, nucleic acid binding, cell-cycle regulation, and cytoskeleton. Moreover, the putative roles of 16 proteins which have not been previously associated to meiosis or were not identified in rice before, are also discussed namely: seven proteins involved in chromosome structure and remodeling, five regulatory proteins [such as SKP1 (OSK), a putative CDK2 like effector], a protein with RNA recognition motifs, a neddylation-related protein, and two microtubule-related proteins. Revealing the proteins involved in early meiotic processes could provide a valuable tool kit to manipulate chromosome associations during meiosis in rice breeding programs. The data have been deposited to the ProteomeXchange with the PXD001058 identifier.

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The SIT4 gene, which encodes protein phosphatase 2A, is required for telomere function in Saccharomyces cerevisiae

Cited by 18 publications

References 42 publications

The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum

The TOR signaling pathway regulates vegetative development and virulence in Fusarium graminearum

Distinct Subsets of Sit4 Holophosphatases Are Required for Inhibition ofSaccharomyces cerevisiaeGrowth by Rapamycin and Zymocin

Unravelling the proteomic profile of rice meiocytes during early meiosis

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