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Your search keyword '"Shimizu, Kiminori"' showing total 216 results
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216 results on '"Shimizu, Kiminori"'

21. Tacrolimus inhibits stress responses and hyphal formation via the calcineurin signaling pathway in Trichosporon asahii.

Author

Kurakado, Sanae, Matsumoto, Yasuhiko, Yamada, Tsuyoshi, Shimizu, Kiminori, Wakasa, Shogo, and Sugita, Takashi

Subjects
CALCINEURIN, TACROLIMUS, CELLULAR signal transduction, TRICHOSPORON, AMINO acid residues, FUNGAL cell walls
Abstract

The pathogenic fungus Trichosporon asahii causes fatal deep‐seated mycosis in immunocompromised patients. Calcineurin, which is widely conserved in eukaryotes, regulates cell growth and various stress responses in fungi. Tacrolimus (FK506), a calcineurin inhibitor, induces sensitivity to compounds that cause stress on the cell membrane and cell wall integrity. In this study, we demonstrated that FK506 affects stress responses and hyphal formation in T. asahii. In silico structural analysis revealed that amino acid residues in the binding site of the calcineurin–FKBP12 complex that interact with FK506 are conserved in T. asahii. The growth of T. asahii was delayed by FK506 in the presence of SDS or Congo red but not in the presence of calcium chloride. FK506 also inhibited hyphal formation in T. asahii. A mutant deficient of the cnb gene, which encodes the regulatory subunit B of calcineurin, exhibited stress sensitivities on exposure to SDS and Congo red and reduced the hyphal forming ability of T. asahii. In the cnb‐deficient mutant, FK506 did not increase the stress sensitivity or reduce hyphal forming ability. These results suggest that FK506 affects stress responses and hyphal formation in T. asahii via the calcineurin signaling pathway. [ABSTRACT FROM AUTHOR]

Published
2023
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36. Pka, Ras and RGS protein interactions regulate activity of AflR, a Zn(II)2Cys6 transription factor in Aspergillus nidulans

Author

Shimizu, Kiminori, Hicks, Julie K., Huang, Tzu-Pi, and Keller, Nancy P.

Subjects
Aspergillus -- Genetic aspects, Aspergillus -- Research, Genetic transcription -- Research, Biological sciences
Abstract

Sterigmatocystin (ST) is a carcinogenic polyketide produced by several filamentous fungi including Aspergillus nidulans. Expression of ST biosynthetic genes (stc genes) requires activity of a Zn(II)2Cys6 transcription factor, AflR. aflR is transcriptionally and post-transcriptionally regulated by a G-protein/cAMP/protein kinase A (PkaA) signaling pathway involving FlbA, an RGS (regulator of G-protein signaling) protein. Prior genetic data showed that FlbA transcriptional regulation of aflR was PkaA dependent. Here we show that mutation of three PkaA phosphorylation sites in AflR allows resumption of stc expression in an overexpression pkaA background but does not remediate stc expression in a [DELTA]flbA background. This demonstrates negative regulation of AflR activity by phosphorylation and shows that FlbA post-transcriptional regulation of aflR is PkaA independent. AflR nucleocytoplasmic location further supports PkaA-independent regulation of AflR by FlbA. GFP-tagged AflR is localized to the cytoplasm when pkaA is overexpressed but nuclearly located in a [DELTA]flbA background. aflR is also transcriptionally and post-transcriptionally regulated by RasA. RasA transcriptional control of aflR is PkaA independent but RasA post-transcriptional control of AflR is partially mediated by PkaA.

Published
2003

49. A Novel Zn2-Cys6 Transcription Factor AtrR Plays a Key Role in an Azole Resistance Mechanism of Aspergillus fumigatus by Co-regulating cyp51A and cdr1B Expressions

Author

Hagiwara, Daisuke, primary, Miura, Daisuke, additional, Shimizu, Kiminori, additional, Paul, Sanjoy, additional, Ohba, Ayumi, additional, Gonoi, Tohru, additional, Watanabe, Akira, additional, Kamei, Katsuhiko, additional, Shintani, Takahiro, additional, Moye-Rowley, W. Scott, additional, Kawamoto, Susumu, additional, and Gomi, Katsuya, additional

Published
2017
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