scholarly journals The F-Box Protein Fbp1 Regulates Virulence of Cryptococcus neoformans Through the Putative Zinc-Binding Protein Zbp1

2021 ◽  
Vol 11 ◽  
Author(s):  
Lian-Tao Han ◽  
Yu-Juan Wu ◽  
Tong-Bao Liu
Keyword(s):  
Translational Regulation ◽  
Binding Protein ◽  
Yeast Cells ◽  
Zinc Binding ◽  
Major Protein ◽  
Fungal Virulence ◽  
Proteomic Approach ◽  
F Box Protein ◽  
Capsule Size

The ubiquitin-proteasome system (UPS) is the major protein turnover mechanism that plays an important role in regulating various cellular functions. F-box proteins are the key proteins of the UPS, responsible for the specific recognition and ubiquitination of downstream targets. Our previous studies showed that the F-box protein Fbp1 plays an essential role in the virulence of C. neoformans. However, the molecular mechanism of Fbp1 regulating the virulence of C. neoformans is still unclear. In this study, we analyzed the potential Fbp1 substrates using an iTRAQ-based proteomic approach and identified the zinc-binding protein Zbp1 as a substrate of Fbp1. Protein interaction and stability assays showed that Zbp1 interacts with Fbp1 and is a downstream target of Fbp1. Ubiquitination analysis in vivo showed that the ubiquitination of Zbp1 is dependent on Fbp1 in C. neoformans. Subcellular localization analysis revealed that the Zbp1 protein was localized in the nucleus of C. neoformans cells. In addition, both deletion and overexpression of the ZBP1 gene led to the reduced capsule size, while overexpression has a more significant impact on capsule size reduction. Fungal virulence assays showed that although the zbp1Δ mutants are virulent, virulence was significantly attenuated in the ZBP1 overexpression strains. Fungal load assay showed that the fungal burdens recovered from the mouse lungs decreased gradually after infection, while no yeast cells were recovered from the brains and spleens of the mice infected by ZBP1 overexpression strains. Thus, our results revealed a new determinant of fungal virulence involving the post-translational regulation of a zinc-binding protein.

scholarly journals The Genomic Sequences Bound to Special AT-rich Sequence-binding Protein 1 (SATB1) In Vivo in Jurkat T Cells Are Tightly Associated with the Nuclear Matrix at the Bases of the Chromatin Loops

1998 ◽  
Vol 141 (2) ◽  
pp. 335-348 ◽  
Author(s):  
Ian de Belle ◽  
Shutao Cai ◽  
Terumi Kohwi-Shigematsu
Keyword(s):  
Nuclear Matrix ◽  
Cpg Island ◽  
Binding Protein ◽  
Jurkat Cells ◽  
Yeast Cells ◽  
Genomic Sequences ◽  
Specific Gene ◽  
Addition Line ◽  
Chromatin Loops

Special AT-rich sequence-binding protein 1 (SATB1), a DNA-binding protein expressed predominantly in thymocytes, recognizes an ATC sequence context that consists of a cluster of sequence stretches with well-mixed A's, T's, and C's without G's on one strand. Such regions confer a high propensity for stable base unpairing. Using an in vivo cross-linking strategy, specialized genomic sequences (0.1–1.1 kbp) that bind to SATB1 in human lymphoblastic cell line Jurkat cells were individually isolated and characterized. All in vivo SATB1-binding sequences examined contained typical ATC sequence contexts, with some exhibiting homology to autonomously replicating sequences from the yeast Saccharomyces cerevisiae that function as replication origins in yeast cells. In addition, LINE 1 elements, satellite 2 sequences, and CpG island–containing DNA were identified. To examine the higher-order packaging of these in vivo SATB1-binding sequences, high-resolution in situ fluorescence hybridization was performed with both nuclear “halos” with distended loops and the nuclear matrix after the majority of DNA had been removed by nuclease digestion. In vivo SATB1-binding sequences hybridized to genomic DNA as single spots within the residual nucleus circumscribed by the halo of DNA and remained as single spots in the nuclear matrix, indicating that these sequences are localized at the base of chromatin loops. In human breast cancer SK-BR-3 cells that do not express SATB1, at least one such sequence was found not anchored onto the nuclear matrix. These findings provide the first evidence that a cell type–specific factor such as SATB1 binds to the base of chromatin loops in vivo and suggests that a specific chromatin loop domain structure is involved in T cell–specific gene regulation.

scholarly journals Studies on the effect of an heterologous fatty acid-binding protein on acyl-CoA oxidase induction in Saccharomyces cerevisiae

1994 ◽  
Vol 301 (2) ◽  
pp. 615-620 ◽  
Author(s):  
I Smaczyńska ◽  
M Skoneczny ◽  
A Kurlandzka
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Binding Protein ◽  
Yeast Cells ◽  
Fatty Acid Binding ◽  
Acid Binding Protein ◽  
Acyl Coa Oxidase

The participation of fatty acid-binding protein (FABP) in the induction of peroxisomal beta-oxidation of fatty acids was investigated in vivo in an heterologous system. Bovine heart FABP was expressed in Saccharomyces cerevisiae under the control of two different promoters: a constitutive one and an oleic acid-inducible one. Constructs were introduced into yeast cells on multicopy and integrating plasmids. The heterologous FABP was present in yeast cells in two isoforms having pI values of about 5 and was able to bind oleic acid. The heterologous FABP had no significant effect on acyl-CoA oxidase activity at various concentrations of the inducing agent.

scholarly journals Rapamycin sensitivity in Saccharomyces cerevisiae is mediated by a peptidyl-prolyl cis-trans isomerase related to human FK506-binding protein.

1991 ◽  
Vol 11 (3) ◽  
pp. 1718-1723 ◽  
Author(s):  
Y Koltin ◽  
L Faucette ◽  
D J Bergsma ◽  
M A Levy ◽  
R Cafferkey ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Binding Protein ◽  
Interleukin 2 ◽  
Yeast Cells ◽  
Ppiase Activity ◽  
Resistant Mutants

Rapamycin is a macrolide antifungal agent with structural similarity to FK506. It exhibits potent immunosuppressive properties analogous to those of both FK506 and cyclosporin A (CsA). Unlike FK506 and CsA, however, rapamycin does not inhibit the transcription of early T-cell activation genes, including interleukin-2, but instead appears to block downstream events leading to T-cell activation. FK506 and CsA receptor proteins (FKBP and cyclophilin, respectively) have been identified and shown to be distinct members of a class of enzymes that possess peptidyl-prolyl cis-trans isomerase (PPIase) activity. Despite the apparent differences in their mode of action, rapamycin and FK506 act as reciprocal antagonists in vivo and compete for binding to FKBP. As a means of rapidly identifying a target protein for rapamycin in vivo, we selected and genetically characterized rapamycin-resistant mutants of Saccharomyces cerevisiae and isolated a yeast genomic fragment that confers drug sensitivity. We demonstrate that the resonse to rapamycin in yeast cells is mediated by a gene encoding a 114-amino-acid, approximately 13-kDa protein which has a high degree of sequence homology with human FKBP; we designated this gene RBP1 (for rapamycin-binding protein). The RBP1 protein (RBP) was expressed in Escherichia coli, purified to homogeneity, and shown to catalyze peptidyl-prolyl isomerization of a synthetic peptide substrate. PPIase activity was completely inhibited by rapamycin and FK506 but not by CsA, indicating that both macrolides bind to the recombinant protein. Expression of human FKBP in rapamycin-resistant mutants restored rapamycin sensitivity, indicating a functional equivalence between the yeast and human enzymes.

Function of Tubulin Binding Proteins in Vivo

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 69-80 ◽  
Author(s):  
James A Fleming ◽  
Leticia R Vega ◽  
Frank Solomon
Keyword(s):  
Binding Proteins ◽  
Binding Protein ◽  
Yeast Cells ◽  
Gene Products ◽  
Salvage Pathway ◽  
Tubulin Binding ◽  
Mutant Cells ◽  
Β Tubulin

Abstract Overexpression of the β-tubulin binding protein Rbl2p/cofactor A is lethal in yeast cells expressing a mutant α-tubulin, tub1-724, that produces unstable heterodimer. Here we use RBL2 overexpression to identify mutations in other genes that affect formation or stability of heterodimer. This approach identifies four genes—CIN1, CIN2, CIN4, and PAC2—as affecting heterodimer formation in vivo. The vertebrate homologues of two of these gene products—Cin1p/cofactor D and Pac2p/cofactor E—can catalyze exchange of tubulin polypeptides into preexisting heterodimer in vitro. Previous work suggests that both Cin2p or Cin4p act in concert with Cin1p in yeast, but no role for vertebrate homologues of either has been reported in the in vitro reaction. Results presented here demonstrate that these proteins can promote heterodimer formation in vivo. RBL2 overexpression in cin1 and pac2 mutant cells causes microtubule disassembly and enhanced formation of Rbl2p-β-tubulin complex, as it does in the α-tubulin mutant that produces weakened heterodimer. Significantly, excess Cin1p/cofactor D suppresses the conditional phenotypes of that mutant α-tubulin. Although none of the four genes is essential for viability under normal conditions, they become essential under conditions where the levels of dissociated tubulin polypeptides increase. Therefore, these proteins may provide a salvage pathway for dissociated tubulin heterodimers and so rescue cells from the deleterious effects of free β-tubulin.

scholarly journals Proteins binding to 5' untranslated region sites: a general mechanism for translational regulation of mRNAs in human and yeast cells.

1994 ◽  
Vol 14 (9) ◽  
pp. 5898-5909 ◽  
Author(s):  
R Stripecke ◽  
C C Oliveira ◽  
J E McCarthy ◽  
M W Hentze
Keyword(s):  
Binding Sites ◽  
Untranslated Region ◽  
Translational Regulation ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Yeast Cells ◽  
General Mechanism ◽  
Translational Repressor

We demonstrate that a bacteriophage protein and a spliceosomal protein can be converted into eukaryotic translational repressor proteins. mRNAs with binding sites for the bacteriophage MS2 coat protein or the spliceosomal human U1A protein were expressed in human HeLa cells and yeast. The presence of the appropriate binding protein resulted in specific, dose-dependent translational repression when the binding sites were located in the 5' untranslated region (UTR) of the reporter mRNAs. Neither mRNA export from the nucleus to the cytoplasm nor mRNA stability was demonstrably affected by the binding proteins. The data thus reveal a general mechanism for translational regulation: formation of mRNA-protein complexes in the 5' UTR controls translation initiation by steric blockage of a sensitive step in the initiation pathway. Moreover, the findings establish the basis for novel strategies to study RNA-protein interactions in vivo and to clone RNA-binding proteins.

scholarly journals The GTP-binding protein Ypt1 is required for transport in vitro: the Golgi apparatus is defective in ypt1 mutants.

1989 ◽  
Vol 109 (3) ◽  
pp. 1015-1022 ◽  
Author(s):  
R A Bacon ◽  
A Salminen ◽  
H Ruohola ◽  
P Novick ◽  
S Ferro-Novick
Keyword(s):  
Golgi Apparatus ◽  
Binding Protein ◽  
Yeast Cells ◽  
Carboxypeptidase Y ◽  
Loss Of Function ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Transport Defect

The YPT1 gene encodes a raslike, GTP-binding protein that is essential for growth of yeast cells. We show here that mutations in the ypt1 gene disrupt transport of carboxypeptidase Y to the vacuole in vivo and transport of pro-alpha-factor to a site of extensive glycosylation in the Golgi apparatus in vitro. Two different ypt1 mutations result in loss of function of the Golgi complex without affecting the activity of the endoplasmic reticulum or soluble components required for in vitro transport. The function of the mutant Golgi apparatus can be restored by preincubation with wild-type cytosol. The transport defect observed in vitro cannot be overcome by addition of Ca++ to the reaction mixture. We have also established genetic interactions between ypt1 and a subset of the other genes required for transport to and through the Golgi apparatus.

scholarly journals Rapamycin sensitivity in Saccharomyces cerevisiae is mediated by a peptidyl-prolyl cis-trans isomerase related to human FK506-binding protein

1991 ◽  
Vol 11 (3) ◽  
pp. 1718-1723 ◽  
Author(s):  
Y Koltin ◽  
L Faucette ◽  
D J Bergsma ◽  
M A Levy ◽  
R Cafferkey ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Binding Protein ◽  
Interleukin 2 ◽  
Yeast Cells ◽  
Ppiase Activity ◽  
Resistant Mutants

Rapamycin is a macrolide antifungal agent with structural similarity to FK506. It exhibits potent immunosuppressive properties analogous to those of both FK506 and cyclosporin A (CsA). Unlike FK506 and CsA, however, rapamycin does not inhibit the transcription of early T-cell activation genes, including interleukin-2, but instead appears to block downstream events leading to T-cell activation. FK506 and CsA receptor proteins (FKBP and cyclophilin, respectively) have been identified and shown to be distinct members of a class of enzymes that possess peptidyl-prolyl cis-trans isomerase (PPIase) activity. Despite the apparent differences in their mode of action, rapamycin and FK506 act as reciprocal antagonists in vivo and compete for binding to FKBP. As a means of rapidly identifying a target protein for rapamycin in vivo, we selected and genetically characterized rapamycin-resistant mutants of Saccharomyces cerevisiae and isolated a yeast genomic fragment that confers drug sensitivity. We demonstrate that the resonse to rapamycin in yeast cells is mediated by a gene encoding a 114-amino-acid, approximately 13-kDa protein which has a high degree of sequence homology with human FKBP; we designated this gene RBP1 (for rapamycin-binding protein). The RBP1 protein (RBP) was expressed in Escherichia coli, purified to homogeneity, and shown to catalyze peptidyl-prolyl isomerization of a synthetic peptide substrate. PPIase activity was completely inhibited by rapamycin and FK506 but not by CsA, indicating that both macrolides bind to the recombinant protein. Expression of human FKBP in rapamycin-resistant mutants restored rapamycin sensitivity, indicating a functional equivalence between the yeast and human enzymes.

scholarly journals A hidden battle in the dirt: soil amoebae interactions withParacoccidioidesspp

2019 ◽  
Author(s):  
Patrícia Albuquerque ◽  
André Moraes Nicola ◽  
Diogo Almeida Gomes Magnabosco ◽  
Lorena da Silveira Derengowski ◽  
Luana Soares Crisóstomo ◽  
...  
Keyword(s):  
Galleria Mellonella ◽  
Acanthamoeba Castellanii ◽  
Pathogenic Fungi ◽  
Yeast Cells ◽  
Its Sequencing ◽  
Fungal Virulence ◽  
Evolution Of Virulence ◽  
Natural Predator ◽  
Molecular Patterns

AbstractParacoccidioidesspp. are thermodimorphic pathogenic fungi endemic to Latin America. Predation is believed to drive the evolution of virulence for soil saprophytes. We evaluated the presence of environmental amoeboid predators in soil from armadillo burrows whereParacoccidioideshad been previously detected and tested if interaction ofParacoccidioideswith amoebae increased fungal virulence. Nematodes, ciliates and amoebae – all potential predators of fungi – grew in cultures from soil samples. Microscopical observation and ITS sequencing identified the amoebae asAcanthamoebaspp,Allovahlkampfia spelaeaandVermamoeba vermiformis. These three amoebae efficiently ingested, killed and digestedParacoccidioidesspp. yeast cells, as did laboratory-adapted axenicAcanthamoeba castellanii. Sequential co-cultivation ofParacoccidioideswithA. castellaniiselected for phenotypical traits related to survival of the fungus within a natural predator as well as in murine macrophages and in vivo (Galleria mellonellaand mice). This increase in virulence is linked to the accumulation of cell wall alpha-glucans, polysaccharides that masks recognition of fungal molecular patterns by host pattern recognition receptors. Altogether, our results indicate thatParacoccidioidesinhabits a complex environment with multiple amoeboid predators that can exert selective pressure to guide the evolution of virulence traits.

Proteins binding to 5' untranslated region sites: a general mechanism for translational regulation of mRNAs in human and yeast cells

1994 ◽  
Vol 14 (9) ◽  
pp. 5898-5909
Author(s):  
R Stripecke ◽  
C C Oliveira ◽  
J E McCarthy ◽  
M W Hentze
Keyword(s):  
Binding Sites ◽  
Untranslated Region ◽  
Translational Regulation ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Yeast Cells ◽  
General Mechanism ◽  
Translational Repressor

We demonstrate that a bacteriophage protein and a spliceosomal protein can be converted into eukaryotic translational repressor proteins. mRNAs with binding sites for the bacteriophage MS2 coat protein or the spliceosomal human U1A protein were expressed in human HeLa cells and yeast. The presence of the appropriate binding protein resulted in specific, dose-dependent translational repression when the binding sites were located in the 5' untranslated region (UTR) of the reporter mRNAs. Neither mRNA export from the nucleus to the cytoplasm nor mRNA stability was demonstrably affected by the binding proteins. The data thus reveal a general mechanism for translational regulation: formation of mRNA-protein complexes in the 5' UTR controls translation initiation by steric blockage of a sensitive step in the initiation pathway. Moreover, the findings establish the basis for novel strategies to study RNA-protein interactions in vivo and to clone RNA-binding proteins.

scholarly journals The p53-binding protein 53BP2 also interacts with Bc12 and impedes cell cycle progression at G2/M.

1996 ◽  
Vol 16 (7) ◽  
pp. 3884-3892 ◽  
Author(s):  
L Naumovski ◽  
M L Cleary
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Binding Protein ◽  
Yeast Cells ◽  
Cycle Progression ◽  
Stable Transfectants ◽  
Partial Clone ◽  
Two Hybrid

Using the yeast two-hybrid system, we have isolated a cDNA (designated BBP, for Bcl2-binding protein) for a protein (Bbp) that interacts with Bcl2. Bbp is identical to 53BP2, a partial clone of which was previously isolated in a two-hybrid screen for proteins that interact with p53. In this study, we show that specific interactions of Bbp/53BP2 with either Bcl2 or p53 require its ankyrin repeats and SH3 domain. These interactions can be reproduced in vitro with bacterially expressed fusion proteins, and competition experiments indicate that Bcl2 prevents p53 from binding to Bbp/53BP2. BBP/53BP2 mRNA is abundant in most cell lines examined, but the protein cannot be stably expressed in a variety of cell types by transfection. In transiently transfected cells, Bbp partially colocalizes with Bcl2 in the cytoplasm and results in an increased number of cells at G2/M, possibly accounting for the inability to obtain stable transfectants expressing the protein. These results demonstrate that a single protein can interact with either Bcl2 or p53 both in yeast cells and in vitro. The in vivo significance of these interactions and their potential consequences for cell cycle progression and cell death remain to be determined.

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