• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1377-1381
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• 2014

In order to discover and develop novel signaling inhibitors from plants, a screening system was established targeting the two-component system of Cryptococcus neoformans by using the wild type and a calcineurin mutant of C. neoformans, based on the counter-regulatory action of high-osmolarity glycerol (Hog1) mitogen-activated protein kinase and the calcineurin pathways in C. neoformans. Among 10,000 plant extracts, that from Harrisonia abyssinica Oliv. exhibited the most potent inhibitory activity against C. neoformans var. grubii H99 with fludioxonil. Bioassay-guided fractionation was used to isolate two bioactive compounds from H. abyssinica, and these compounds were identified as chebulagic acid and chebulanin using spectroscopic methods. These compounds specifically inhibited the calcineurin pathway in C. neoformans. Moreover, they exhibited potent antifungal activities against various human pathogenic fungi with minimum inhibitory concentrations ranging from 0.25 to over $64{\mu}g/ml$.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.11-16
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• 2009

Magnaporthe oryzae, the causal agent of rice blast, forms a specialized infection structure, called an appressorium, which is crucial for penetration and infection of the host plant. Pharmacological data suggest that calcium/calmodulindependent signaling is involved in appressorium formation in this fungus. To understand the role of the calcium/calmodulin-activated protein phosphatase on appressorium formation at the molecular level, MCNA, a gene encoding the catalytic subunit of calcineurin, was functionally characterized in M. oryzae. Transformants expressing sense/antisense RNA of MCNA exhibited significant reductions in mycelial growth, conidiation, appressorium formation, and pathogenicity. cDNA of MCNA functionally complemented a calcineurin disruptant strain (cmp1::LEU2 cmp2::HIS3) of Saccharomyces cerevisiae. These data suggest that calcineurin A plays important roles in signal transduction pathways involved in the infection-related morphogenesis and pathogenicity of M. oryzae.

• Molecules and Cells
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• v.28 no.5
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• pp.455-461
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• 2009

Calcineurin is a $Ca^{2+}$/Calmodulin activated Ser/Thr phosphatase that is well conserved from yeast to human. It is composed of catalytic subunit A (CnA) and regulatory subunit B (CnB). C. elegans homolog of CnA and CnB has been annotated to tax-6 and cnb-1, respectively and in vivo function of both genes has been intensively studied. In C. elegans, calcineurin play roles in various signaling pathways such as fertility, movement, body size regulation and serotonin-mediated egg laying. In order to understand additional signaling pathway(s) in which calcineurin functions, we screened for binding proteins of TAX-6 and found a novel binding protein, HLH-11. The HLH-11, a member of basic helix-loop-helix (bHLH) proteins, is a putative counterpart of human AP4 transcription factor. Previously bHLH transcription factors have been implicated to regulate many developmental processes such as cell proliferation and differentiation, sex determination and myogenesis. However, the in vivo function of hlh-11 is largely unknown. Here, we show that hlh-11 is expressed in pharynx, intestine, nerve cords, anal depressor and vuvla muscles where calcineurin is also expressed. Mutant analyses reveal that hlh-11 may have role(s) in regulating body size and reproduction. More interestingly, genetic epistasis suggests that hlh-11 may function to regulate serotoninmediated egg laying at the downstream of tax-6.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.162.4-162
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• 2003

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1696-1700
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• 2016

In order to discover plant-derived signaling pathway inhibitors with antifungal properties, a two-component screening system utilizing the calcineurin and Hog1 mitogen-activated protein kinase pathways responsible for the virulence networks of Cryptococcus neoformans was employed, owing to the counter-regulatory actions of these pathways. Of the 1,000 plant extracts tested, two bioactive compounds from Miliusa sinensis were found to act specifically on the calcineurin pathway of C. neoformans. These compounds, identified as pashanone and 5-hydroxy-6,7-dimethoxyflavanone, exhibited potent antifungal activities against various human pathogenic fungi with minimum inhibitory concentration values ranging from 4.0 to >128 μg/ml.

• Korean Journal of Veterinary Research
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• v.44 no.1
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• pp.7-13
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• 2004

Severe hypertension (>180 mmHg) develops in spontaneously hypertensive rats (SHR) after 12 wk-old; however, it is not clear whether what kinds of molecular mechanism leads to altered cardiac performance following developmental stages in SHR. Also, although the effect of calcineurin (Cn) to promote cardiomyocyte hypertrophy in vivo and in vitro is established, its overall necessity as a hypertrophic mediator is currently an area of ongoing debate. Thus, we have examined i) body weight and blood pressure, ii) differences of expression and distribution of signaling molecules such as Cn, protein kinase B/Akt (PKB/Akt), and extracellular signal-regulated kinase (ERK) between SHR and their age-matched control Wistar-Kyoto (WKY) rats following developmental stages. In 16 wk-old SHR compared with WKY, 2-dimentional echocardiography showed cardiac enlargement and hypertrophy of left ventricle, significantly. Taken together, we suggest that Cn is associated with hereditary cardiac hypertrophy, the process being related to the molecular signaling mechanisms involving PKB/Akt and ERK.

• BMB Reports
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• v.41 no.6
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• pp.455-460
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• 2008

Calcineurin (Cn) is a serine/threonine phosphatase implicated in a wide variety of biological responses. To identify proteins that mediate Cn signaling pathway effects, we used yeast two-hybrid assays to screen for Cn interacting proteins, discovering a protein encoded by the gene, cnp-2 (Y46G5A.10). Utilizing serially deleted forms of Cn as baits, we demonstrated that the catalytic domain of Cn (TAX-6) binds with CNP-2, and this physical interaction was able to be reconstituted in vitro, supporting our yeast two-hybrid results. cnp-2 is a nematode-specific novel gene found in C. elegans as well as its closest relative, C. briggsae. CNP-2 was strongly expressed in the intestine of C. elegans. To study the function of cnp-2, we performed cnp-2 RNAi knock-down and characterized phenotypes associated with Cn mutants. However, no gross defects were revealed in these RNAi experiments. CNP-2 was proven to be a Cn binding protein; however, its role remains to be elucidated.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.6
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• pp.353-361
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• 2005

The interaction of cyclosporine A (CsA), an immunosuppressant, with rat brain Kv1.5 (Kv1.5) channels, which were stably expressed in Chinese hamster ovary cells, was investigated using the whole-cell patch-clamp technique. CsA reversibly blocked Kv1.5 currents at +50 mV in a reversible concentrationdependent manner with an apparent $IC_{50}$ of 1.0μM. Other calcineurin inhibitors (cypermethrin, autoinhibitory peptide) had no effect on Kv1.5 and did not prevent the inhibitory effect of CsA. Fast application of CsA led to a rapid and reversible block of Kv1.5, and the onset time constants of the CsA-induced block were decreased in a concentration-dependent manner. The CsA-induced block of Kv1.5 channels was voltage-dependent, with a steep increase over the voltage range of channel opening. However, the block exhibited voltage independence over the voltage range in which channels were fully activated. The rate constants for association and dissociation of CsA were $7.0{\mu}M{-1}s^{-1}$ and $8.1s^{-1}$, respectively. CsA slowed the deactivation time course, resulting in a tail crossover phenomenon. Block of Kv1.5 by CsA was use-dependent. CsA also blocked Kv1.3 currents at +50 mV in a reversible concentration-dependent manner with an apparent $IC_{50}$ of $1.1{\mu}M$. The same effects of CsA on Kv1.3 were also observed in excised inside-out patches when applied to the internal surface of the membrane. The present results suggest that CsA acts directly on Kv1.5 currents as an open-channel blocker, independently of the effects of CsA on calcineurin activity.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1349-1353
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• 2007

Calcineurin is a calmodulin dependent protein that functions as a regulator of muscle cell growth and function. Agents capable of interacting with calcineurin could have important applications in muscle disease treatment as well as in the improvement of livestock production. Calsarcins comprise a family of muscle-specific calcineurin binding proteins which play an important role in modulating the function of calcineurin in muscle cells. Recently, we described the first two members of the calsarcin family (calsarcin-1 and calsarcin-2) in the pig. Here, we characterized the third member of the calsarcin family, calsarcin-3, which is also expressed specifically in skeletal muscle. However, unlike calsarcin-1 and calsarcin-2, the calsarcin-3 mRNA expression in skeletal muscle kept rising throughout the prenatal and postnatal development periods. In addition, radiation hybrid mapping indicated that porcine calsarcin-3 mapped to the distal end of the q arm of pig chromosome 2 (SSC2). A C/T single nucleotide polymorphism site in exon 5 was genotyped using the denaturing high performance liquid chromatography (DHPLC) method and the allele frequencies at this locus were significantly different among breeds.

• Korean Journal of Transplantation
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• v.28 no.3
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• pp.165-168
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• 2014

The recipient candidate was a 51-year-old male with end-stage renal disease owing to diabetes mellitus. The initial immunosuppressive regimen included basiliximab for induction and tacrolimus, mycophenolate mofetil, and steroids. Urine output was 413 mL/day on the operative day and 100 mL/day on the postoperative day (POD) 1. There was no definite stenosis of the ureter or vessels. He had anuria on POD 2~4 and he had undergone hemodialysis. His serum creatinine level did not decrease. Therefore, a graft biopsy was performed on POD 4. The pathologic finding was consistent with acute calcineurin inhibitor (CNI) toxicity. There was no evidence of rejection or acute tubular necrosis. Anuria continued on POD 6; therefore, we started sirolimus instead of a CNI based regimen. Graft function was gradually recovered 1 day after reduction of CNI dose and hemodialysis was stopped. The serum creatinine level was normalized on POD 10. He was discharged on POD 21.