Properties of Various
            <i>RHO1</i>
            Mutant Alleles of
            <i>Cryptococcus neoformans</i>

Chang, Yun C.; Penoyer, L.

doi:10.1128/jb.182.17.4987-4991.2000

Cited by 20 publications

(20 citation statements)

References 39 publications

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“…Either of these hypotheses is supported by previous work in which C. neoformans rho1 G15V and rho1 Q64L point mutants similar to the two used in this study were overexpressed in S. cerevisiae under the control of the GAL1 promoter. When S. cerevisiae was grown on galactose, both alleles inhibited growth although the Q64L allele had a more severe defect than the G15V allele (20).…”

Section: Discussionmentioning

confidence: 99%

“…The C. neoformans constitutively active rho1 mutant strains were constructed by nucleotide substitution mutations in the phosphate or magnesium binding sites to create a deregulated GTPase (20). PCR products were generated using overlap PCR technology (22).…”

Section: Methodsmentioning

confidence: 99%

“…In S. cerevisiae, two specific point mutants of RHO1 were each shown to be constitutively active, and both prevent intrinsic and GTPase-activating protein (GAP)-induced GTP hydrolysis, locking the strains in the activated form (36). The analogous substitutions in C. neoformans RHO1 were predicted to be constitutively active based on amino acid conservation and homology to Rho1 proteins from other organisms and growth phenotypes when these mutants were heterologously expressed in S. cerevisiae (20). We generated C. neoformans strains carrying these alleles with amino acid substitutions of Val for Gly at amino acid 15 or Leu for Gln at amino acid 64 in the Mpk1 Flag-tagged strain.…”

Section: G15v and Rho1mentioning

confidence: 99%

“…C. neoformans is thought to initially establish infection in (20), were previously described as constitutively active based on amino acid conservation and homology to Rho1 proteins from other organisms. We generated these mutants in the KN99 background along with S. cerevisiae (Sc) Rho1p.…”

Section: Identification Of C Neoformans Rho Gtpasesmentioning

confidence: 99%

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Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 Signaling Pathway in Response to Thermal Stress

2013

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To initiate and establish infection in mammals, the opportunistic fungal pathogen Cryptococcus neoformans must survive and thrive upon subjection to host temperature. Primary maintenance of cell integrity is controlled through the protein kinase C1 (PKC1) signaling pathway, which is regulated by a Rho1 GTPase in Saccharomyces cerevisiae. We identified three C. neoformans Rho GTPases, Rho1, Rho10, and Rho11, and have begun to elucidate their role in growth and activation of the PKC1 pathway in response to thermal stress. Western blot analysis revealed that heat shock of wild-type cells resulted in phosphorylation of Mpk1 mitogen-activated protein kinase (MAPK). Constitutive activation of Rho1 caused phosphorylation of Mpk1 independent of temperature, indicating its role in pathway regulation. A strain with a deletion of RHO10 also displayed this constitutive Mpk1 phosphorylation phenotype, while one with a deletion of RHO11 yielded phosphorylation similar to that of wild type. Surprisingly, like a rho10⌬ strain, a strain with a deletion of both RHO10 and RHO11 displayed temperature sensitivity but mimicked wild-type phosphorylation, which suggests that Rho10 and Rho11 have coordinately regulated functions. Heat shock-induced Mpk1 phosphorylation also required the PKC1 pathway kinases Bck1 and Mkk2. However, Pkc1, thought to be the major regulatory kinase of the cell integrity pathway, was dispensable for this response. Together, our results argue that Rho proteins likely interact via downstream components of the PKC1 pathway or by alternative pathways to activate the cell integrity pathway in C. neoformans.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: G15v and Rho1mentioning

confidence: 99%

Section: Identification Of C Neoformans Rho Gtpasesmentioning

confidence: 99%

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Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 Signaling Pathway in Response to Thermal Stress

2013

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“…Although many signaling elements have yet to be described, the cryptococcal cAMP signal transduction pathway plays a central role in cellular pro- on May 11, 2018 by guest http://aac.asm.org/ cesses including encapsulation, melanin production, filamentation, mating, and virulence (1,17,59). The cryptococcal RHO1 gene, down-regulated 3.5-fold in the present study (Table 2), encodes the Rho1 protein, which has a high degree of identity with Rho1p in other fungal species (10,54). The Rho GTPases belong to the Ras-related superfamily of small G proteins.…”

Section: Resultsmentioning

confidence: 87%

Differential Gene Expression in Auristatin PHE-Treated Cryptococcus neoformans

Woyke

Berens

Hoelzinger

et al. 2004

Antimicrob Agents Chemother

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The antifungal pentapeptide auristatin PHE was recently shown to interfere with microtubule dynamics and nuclear and cellular division in the opportunistic pathogen Cryptococcus neoformans. To gain a broader understanding of the cellular response of C. neoformans to auristatin PHE, mRNA differential display (DD) and reverse transcriptase PCR (RT-PCR) were applied. Examination of approximately 60% of the cell transcriptome from cells treated with 1.5 times the MIC (7.89 M) of auristatin PHE for 90 min revealed 29 transcript expression differences between control and drug-treated populations. Differential expression of seven of the transcripts was confirmed by RT-PCR, as was drug-dependent modulation of an additional seven transcripts by RT-PCR only. Among genes found to be differentially expressed were those encoding proteins involved in transport, cell cycle regulation, signal transduction, cell stress, DNA repair, nucleotide metabolism, and capsule production. For example, RHO1 and an open reading frame (ORF) encoding a protein with 91% similarity to the Schizophyllum commune 14-3-3 protein, both involved in cell cycle regulation, were down-regulated, as was the gene encoding the multidrug efflux pump Afr1p. An ORF encoding a protein with 57% identity to the heat shock protein HSP104 in Pleurotus sajor-caju was up-regulated. Also, three transcripts of unknown function were responsive to auristatin PHE, which may eventually contribute to the elucidation of the function of their gene products. Further study of these differentially expressed genes and expression of their corresponding proteins are warranted to evaluate how they may be involved in the mechanism of action of auristatin PHE. This information may also contribute to an explanation of the selectivity of auristatin PHE for C. neoformans. This is the first report of drug action using DD in C. neoformans.

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Current Awareness

2001

Yeast

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In order to keep subscribers up‐to‐date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly‐published material on yeasts. Each bibliography is divided into 10 sections. 1 Books, Reviews & Symposia; 2 General; 3 Biochemistry; 4 Biotechnology; 5 Cell Biology; 6 Gene Expression; 7 Genetics; 8 Physiology; 9 Medical Mycology; 10 Recombinant DNA Technology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. (4 weeks journals ‐ search completed 20th Sept. 2000)

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Properties of Various RHO1 Mutant Alleles of Cryptococcus neoformans

Cited by 20 publications

References 39 publications

Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 Signaling Pathway in Response to Thermal Stress

Role of Cryptococcus neoformans Rho1 GTPases in the PKC1 Signaling Pathway in Response to Thermal Stress

Differential Gene Expression in Auristatin PHE-Treated Cryptococcus neoformans

Current Awareness

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